Medical imaging method, medical imaging apparatus, and medical imaging system

Abstract

To obtain fluorescence imaging data with reduced or eliminated artifacts. [Solution] The medical imaging method according to the embodiment includes acquiring imaging data including at least fluorescence imaging data, detecting artifact data within the fluorescence imaging data, generating corrected fluorescence imaging data by removing the artifact data or by changing the artifact data within the fluorescence imaging data to a specific value, and generating an image based on the corrected fluorescence imaging data.

Description

[Technical Field]

[0001] Embodiments disclosed herein relate to medical imaging methods, medical imaging devices, and medical imaging systems. [Background technology]

[0002] Flexible optical imaging devices (e.g., endoscopes, flexible borescopes) enable imaging of internal tissues, organs, and structures. For example, in cardiology, optical coherence tomography (OCT)-capable flexible optical imaging devices are used to acquire depth-resolved images of samples (e.g., tissues, organs). Some flexible optical imaging devices also utilize fluorescence imaging, such as near-infrared fluorescence (NIRF) (e.g., near-infrared autofluorescence (NIRAF)). Fluorescence imaging allows for the visualization of molecular processes (e.g., biological processes in organisms). Flexible optical imaging devices, including a flexible body, coils, and optical probes, can be inserted into lumens (e.g., blood vessels) and manipulated within cavities. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-090723 [Overview of the project] [Problems that the invention aims to solve]

[0004] One of the problems that the embodiments disclosed herein and in the drawings aim to solve is obtaining fluorescence imaging data with reduced or eliminated artifacts. However, the problems that the embodiments disclosed herein and in the drawings aim to solve are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described later can also be positioned as other problems. [Means for solving the problem]

[0005] The medical imaging method according to the embodiment comprises acquiring imaging data including at least fluorescence imaging data, detecting artifact data within the fluorescence imaging data, generating corrected fluorescence imaging data by removing the artifact data or by changing the artifact data within the fluorescence imaging data to a specific value, and generating an image based on the corrected fluorescence imaging data. [Brief explanation of the drawing]

[0006] [Figure 1] Figure 1 is a schematic diagram showing an exemplary embodiment of a medical imaging system. [Figure 2] Figure 2 is a schematic diagram of an exemplary embodiment of the medical imaging system shown in Figure 1, illustrating the details of the probe interface subsystem. [Figure 3A] Figure 3A shows an exemplary embodiment of a curved optical imaging device. [Figure 3B] Figure 3B shows an exemplary embodiment of a curved optical imaging device. [Figure 4] Figure 4 is a schematic diagram of an exemplary embodiment of the medical imaging system shown in Figure 1, illustrating the details of the probe interface subsystem. [Figure 5] Figure 5 shows an exemplary embodiment of a user interface screen. [Figure 6] Figure 6 shows an exemplary embodiment of a workflow for reducing or eliminating image artifacts generated from fluorescence detection data. [Figure 7A] Figure 7A shows an exemplary embodiment of a workflow for removing or replacing artifacts in fluorescence detection data. [Figure 7B] Figure 7B shows an exemplary embodiment of a workflow for removing or replacing artifacts in fluorescence detection data. [Figure 8A] Figure 8A shows an exemplary embodiment of a set of fluorescence images that are unfolded and displayed in a planar manner. [Figure 8B]FIG. 8B is a diagram showing an example of an angular position θ represented by pixel P. [Figure 9] FIG. 9 is a diagram showing an exemplary embodiment of an operation flow for reducing or eliminating artifacts in an image generated from fluorescence detection data. [Figure 10] FIG. 10 is a diagram showing an exemplary embodiment of an operation flow for reducing or eliminating artifacts in an image generated from fluorescence detection data. [Figure 11] FIG. 11 is a diagram showing an exemplary embodiment of an operation flow for detecting artifacts in OCT detection data. [Figure 12A] FIG. 12A is a diagram showing an exemplary embodiment of an OCT image. [Figure 12B] FIG. 12B is a diagram showing the OCT image of FIG. 12A in a different coordinate system. [Figure 13A] FIG. 13A is a diagram showing the sum of pixel values of the OCT image shown in FIG. 12A. [Figure 13B] FIG. 13B is a diagram showing the difference between the sum of angles in the vicinity of the angle shown in FIG. 13A and the sum of FIG. 13A. [[ID=​​​​​​​​​​​​​​​​​​FIG. 18 is a view showing an exemplary embodiment of an operation flow for replacing artifacts in fluorescence detection data. [Figure 19] FIG. 19 is a view showing an exemplary embodiment of an operation flow for displaying a fluorescence image with replaced artifacts. [Figure 20A] FIG. 20A is a view showing a fluorescence image including artifacts. [Figure 20B] FIG. 20B is a view showing the display of a fluorescence image in which pixel values corresponding to guide wire artifacts are replaced with invalid values. [Figure 21] FIG. 21 is a view showing an exemplary embodiment of a user interface for allowing a user to select a region where artifact detection is to be performed. [Figure 22] FIG. 22 is a view showing an exemplary embodiment of a user interface for allowing a user to select a region where artifact detection is to be performed. [Figure 23] FIG. 23 is a schematic view of an exemplary embodiment of an imaging station. [Figure 24A] FIG. 24A is a view showing an example of a series of tomographic OCT images. [Figure 24B] FIG. 24B is a view showing an example of a longitudinal section of a lumen generated from OCT detection data. [Figure 24C] FIG. 24C is a view showing an example of a series of fluorescence images. [Figure 25A] FIG. 25A is a view showing the calculation of the angular range of a guide wire. [Figure 25B] FIG. 25B is a view showing the calculation of the angular range of a guide wire.

DETAILED DESCRIPTION OF THE INVENTION

[0007] The following paragraphs describe several embodiments for illustrative purposes. Other embodiments may include alternatives, equivalents, and variations. Furthermore, the embodiments described herein may include some novel features, but one particular feature is not necessarily essential to any embodiment of the apparatus, system, or method described herein. Also, some embodiments may include features from two or more of the embodiments described below.

[0008] Furthermore, the conjunction "or" as used herein generally means an inclusive "or," but when it is explicitly stated or suggested by the context that it means an exclusive "or," it means an exclusive "or." Also, terms such as "first," "second," etc., as used herein do not necessarily imply relationships such as order, sequence, or priority. These terms are used to distinguish one component, action, element, group, set, etc. from another without expressing relationships such as order, sequence, or priority. That is, a first element, component, area, part, section, etc., may be referred to as a second element, component, area, part, section, etc., for distinction.

[0009] Furthermore, in the following descriptions and drawings, similar reference numbers indicate identical, similar, or equivalent features. The letters at the end of the reference number indicate specific examples of the features identified by that reference number.

[0010] Furthermore, several embodiments are described in the following paragraphs.

[0011] (1) A medical imaging method comprises acquiring imaging data including at least fluorescence imaging data, detecting artifact data in the fluorescence imaging data, generating corrected fluorescence imaging data by removing the artifact data or by changing the artifact data in the fluorescence imaging data to a specific value, and generating an image based on the corrected fluorescence imaging data.

[0012] (2) In the medical imaging method described in (1), the imaging data further includes optical coherence tomography (OCT) imaging data, and the artifact data is detected based on the OCT imaging data.

[0013] (3) In the medical imaging method described in (2), detecting the artifact data is: To detect a first angular position that includes an OCT imaging value that changes beyond a first threshold, Detecting a second angular position that includes an OCT imaging value that changes beyond a second threshold, and This includes defining the detected range between the first angular position and the second angular position as the artifact data.

[0014] (4) In the medical imaging method described in (1), the artifact data is detected based on information about structures shown in the fluorescence imaging data.

[0015] In the medical imaging method described in (5)(4), the structure is a guidewire or a guide catheter.

[0016] (6)(1) The medical imaging method described above further includes generating the corrected fluorescence imaging data by changing the fluorescence imaging data within a predetermined range near the artifact data to the specific value.

[0017] (7) In the medical imaging method described in (1), the specific value is zero or null.

[0018] (8) In the medical imaging method described in (1), the region of the image corresponding to the artifact data is displayed in a predetermined color.

[0019] (9) The medical imaging method described in (1) further comprises analyzing the modified fluorescence imaging data.

[0020] The medical imaging method described in (10)(1) is (i) Obtain a selected distal frame from the fluorescence imaging data and identify the frame of the fluorescence imaging data with a frame number smaller than the frame number of the distal frame which is artifact data, or (ii) further comprising obtaining a selected proximal frame from the fluorescence imaging data and identifying a frame of the fluorescence imaging data with a frame number greater than the frame number of the proximal frame which is artifact data.

[0021] (11) A medical imaging device comprises at least one processor and at least one computer-readable storage medium that communicates with the at least one processor. The at least one computer-readable storage medium stores instructions for the at least one processor and the at least one computer-readable storage medium. The instructions are, Acquire imaging data that includes at least fluorescence imaging data. To detect artifact data in the aforementioned fluorescence imaging data, By removing the artifact data or by changing the artifact data in the fluorescence imaging data to a specific value, corrected fluorescence imaging data is generated, and The system is configured to generate an image based on the modified fluorescence imaging data.

[0022] In the medical imaging apparatus described in (12)(11), the imaging data further includes optical coherence tomography (OCT) imaging data, and the artifact data is detected based on the OCT imaging data.

[0023] In the medical imaging device described in (13)(12), To detect the artifact data, the instruction causes the at least one processor and the at least one computer-readable storage medium to perform the following operations: To detect a first angular position that includes an OCT imaging value that changes beyond a first threshold, Detecting a second angular position that includes an OCT imaging value that changes beyond a second threshold, and The system is configured to define the detected range between the first angular position and the second angular position as the artifact data.

[0024] In the medical imaging apparatus described in (14)(11), the instruction causes the at least one processor and the at least one computer-readable storage medium to further detect the artifact data based on information relating to structures shown in the fluorescence imaging data.

[0025] In the medical imaging device described in (15)(11), The at least one computer-readable storage medium is connected to the at least one processor and the at least one computer-readable storage medium. The system further stores instructions for changing the fluorescence imaging data located within a predetermined range near the artifact data to the specific value.

[0026] In the medical imaging apparatus described in (16)(11), the specific value is zero or null.

[0027] In the medical imaging apparatus described in (17)(11), the region of the image corresponding to the artifact data is displayed in a predetermined color.

[0028] In the medical imaging apparatus described in (18)(11), the at least one computer-readable storage medium further stores instructions for the at least one processor and the at least one computer-readable storage medium to perform the analysis of the modified fluorescence imaging data.

[0029] (19) The medical imaging system includes a probe interface subsystem and The system comprises a patient interface unit, a curved optical imaging device, at least one processor, and at least one computer-readable storage medium that communicates with the at least one processor. The at least one computer-readable storage medium stores instructions for the at least one processor and the at least one computer-readable storage medium. The instructions are, Acquire imaging data that includes at least fluorescence imaging data. To detect artifact data in the aforementioned fluorescence imaging data, By removing the artifact data or by changing the artifact data in the fluorescence imaging data to a specific value, corrected fluorescence imaging data is generated, and The system is configured to generate an image based on the modified fluorescence imaging data.

[0030] In the medical imaging system described in (20)(19), the probe interface subsystem, the patient interface unit, and the curved optical imaging device perform both optical coherence tomography and fluorescence imaging.

[0031] This disclosure generally relates to medical devices and describes exemplary embodiments of optical probes. Embodiments relating to optical probes and their components are described in terms of their states in three-dimensional space. In this specification, “position” means the position of an object or part of an object in three-dimensional space (e.g., three degrees of freedom of movement along the Cartesian coordinate axes x, y, z). Also, “orientation, setting” means the rotational arrangement of an object or part of an object (e.g., three degrees of freedom of rotation along the Cartesian coordinate axes x, y, z, e.g., roll, pitch, yaw). “Posture” means the position of an object or part of an object within at least one degree of freedom of movement, and the orientation of said object or part of an object within at least one degree of freedom of rotation (up to six degrees of freedom of rotation). Also, “shape” means the set of postures, positions, or orientations measured along the elongated body of an object.

[0032] As is well known in the field of medical devices, "proximal" and "distal" are used in relation to the manipulation of the tip of an instrument that extends from the user to the site of surgery or diagnosis. In this regard, "proximal" refers to the part of the instrument closer to the user (e.g., the handle), and "distal" refers to the part of the instrument further away from the user, closer to the site of surgery or diagnosis (the tip). Also, for convenience and clarity, spatial terms such as "vertical," "horizontal," "up," and "down" are used in relation to drawings, but since surgical instruments are used in various orientations and positions, these terms are not limited or absolute.

[0033] In one embodiment, a multimodality OCT-NIRAF imaging system comprising an imaging station and a multimodality curved optical imaging device acquires aligned OCT-NIRAF images of a lumen sample, such as a cardiovascular sample. In one embodiment, the OCT image is acquired by a wavelength-swept laser with a central wavelength of 1,310 nanometers (nm) and a bandwidth of approximately 130 nm. The NIRAF image is acquired by exciting the lumen sample at 633 nm and detecting fluorescence emission in the wavelength range of 680 nm to 900 nm. The OCT irradiation light (OCT light) and excitation light (e.g., NIRAF excitation light) reach the sample via a single double-clad optical fiber (DCF) located within the curved optical imaging device. The curved optical imaging device is connected to the imaging station via a patient interface unit (PIU). The PIU provides a beam coupler (to direct the light) and a pullback unit that performs a mechanical helical scan. In one embodiment, synchronized and aligned OCT and NIRAF data are acquired at a rate of at least 200 frames per second (fps) and a pullback rate of 10 to 40 mm / s. Each OCT-NIRAF image frame contains approximately 500 A-lines.

[0034] Figure 1 is a schematic diagram of an exemplary embodiment of a medical imaging system 10. The medical imaging system 10 comprises an imaging station 100 which is a specially configured computing device (e.g., desktop, laptop, server, workstation), a curved optical imaging device 201 (e.g., catheter 201), a patient interface unit (PIU) 210, a probe interface subsystem (including an OCT module and a NIRAF module) 300, and a display device 500.

[0035] A curved optical imaging device 201 is an instrument that uses light guided by an imaging core (e.g., an optical probe) to observe cavities and organs in the body. For example, a curved optical imaging device 201 is an endoscope, and the medical procedure of inserting an endoscope into an opening in the body is called an endoscopic examination. Specialized endoscopes are generally named after how and where they are used. Examples include bronchoscopes (bronchus), sigmoidoscopy (rectum), cystoscopes (bladder), pyeloscopes (kidneys), laryngoscopes (larynx), otoscopes (ears), arthroscopes (joints), laparoscopes (abdomen), and gastrointestinal endoscopes.

[0036] The medical imaging system 10 is a multimodal optical coherence tomography (MMOCT) system (e.g., a multimodal wavelength-swept OCT system) equipped with interferometric OCT modality and fluorescence modality. The medical imaging system 10 can perform both OCT imaging (optical coherence tomography) and fluorescence imaging (e.g., autofluorescence imaging, near-infrared autofluorescence imaging, fluorescence lifetime imaging, etc.) and is used, for example, in intravascular imaging. Furthermore, it can be used in conjunction with a balloon catheter during esophageal imaging and similar intravascular lumen imaging.

[0037] The curved optical imaging device 201 is capable of performing optical scanning procedures inside lumens (e.g., blood vessels, bronchi, intestines, trachea, external auditory canal), cavities (e.g., stomach, nasal cavity), or other structures. In Figure 1, the curved optical imaging device 201 extends into the sample 601 (e.g., the patient's lumen). During the optical scanning procedure, the probe interface subsystem 300 generates light (e.g., OCT light, excitation light) and supplies the generated light to the curved optical imaging device 201. The curved optical imaging device 201 transports the light (e.g., OCT light, excitation light) to its distal end, which is the light output port. At the distal end, the curved optical imaging device 201 also collects light (e.g., OCT light, fluorescence) emitted, scattered, or reflected by the sample 601.

[0038] The collected light is transported from the distal end of the curved optical imaging device 201 through the PIU 210 to the probe interface subsystem 300. Based on the light reception, the probe interface subsystem 300 generates a detection signal including detection data (e.g., a series of first detection data, such as a series of first detection data sets) and supplies the detection signal to the imaging station 100. The detection signal may include detection signals from multiple modalities, such as OCT detection signals and fluorescence detection signals. That is, the detection data may include, for example, OCT detection data or fluorescence detection data. Fluorescence detection data is an example of fluorescence imaging data. OCT detection data is an example of OCT imaging data. Furthermore, detection data including fluorescence detection data and / or OCT detection data is an example of imaging data.

[0039] Based on the detection data, the imaging station 100 generates one or more optical scan images (e.g., a series of optical scan images). For example, each of the series of optical scan images is generated from each of the series of detection data sets. The imaging station 100 supplies one or more optical scan images to the display device 500, and the display device 500 displays one or more optical scan images. For example, the imaging station 100 generates a user interface including one or more optical scan images and transmits it to the display device 500. Examples of optical scan images include: OCT images (images generated from OCT detection data), fluorescence images (images generated from fluorescence detection data), and multimodal images (e.g., OCT fluorescence images such as OCT fluorescence images after alignment). Furthermore, in one embodiment, each optical scan image is formed by a set of frames. Each frame is a one-dimensional pixel array.

[0040] Figure 2 is a schematic diagram of an exemplary embodiment of the medical imaging system 10 of Figure 1, showing details of the probe interface subsystem 300. Figures 3A-3B show exemplary embodiments of the curved optical imaging device 201. Figure 3A is a partial cross-sectional view of the curved optical imaging device 201. Figure 3B is a partial perspective cross-sectional view of the curved optical imaging device 201.

[0041] The medical imaging system 10 comprises an imaging station 100 which is a specially configured computing device (e.g., desktop, laptop, server, workstation), a curved optical imaging device 201, a patient interface unit (PIU) 210, a probe interface subsystem 300, and a display device 500. The probe interface subsystem 300 comprises an OCT light source 301, a splitter 302, a first circulator 303, a reflector 304, a second circulator 305, a coupler 306, a first detector 307, a second detector 308, an excitation light source 310, a third detector 313 (e.g., a photomultiplier tube (PMT), a photodetector), a first data acquisition electronic device (DAQ1) 401, a second data acquisition electronic device (DAQ2) 402, and other components as described below.

[0042] The imaging station 100 is connected to external systems such as a display device 500 and a picture archiving and communication system (PACS) 1400. The imaging station 100 is an example of a medical imaging device.

[0043] As shown in Figure 2, the OCT modality consists of an interferometer (e.g., a Michelson interferometer) having a sample arm 32 and a reference arm 31, an OCT light source 301, a detection unit 309, a data acquisition unit (DAQ) 400 (including a first data acquisition electronic device (DAQ1) 401 and a second data acquisition electronic device (DAQ1) 402), and an imaging station 100. The sample arm 32 includes a patient interface unit (PIU) 210 and a curved optical imaging device 201 (e.g., a fiber catheter). The reference arm 31 includes a circulator 303 and a reflector 304. The elements of the OCT modality constitute an OCT module.

[0044] The fluorescence modality consists of an excitation light source 310, a curved optical imaging device 201, a third detector 313 (also referred to as a fluorescence detector 313), a data acquisition unit (DAQ) 400, and an imaging station 100. In the fluorescence modality, the excitation light source 310 is connected to the PIU 210 via an optical fiber 326. The elements of the fluorescence modality constitute a fluorescence module.

[0045] In one embodiment, the OCT light source 301 of the OCT modality is a wavelength-swept laser (1310 nm + / - 50 nm), and the excitation light source 310 of the fluorescence modality is a helium-neon (He:Ne) laser or laser diode with a central wavelength of approximately 633 nm.

[0046] The curved optical imaging device 201 (e.g., a catheter) comprises a flexible tubular body 202, a coil 203, a protector 204, and an imaging core 205 (e.g., an optical probe). The flexible tubular body 202 (e.g., a catheter sheath) surrounds the imaging core 205. The flexible tubular body 202 may also be referred to as the flexible body.

[0047] The imaging core 205 comprises a double-clad optical fiber (DCF) 206 and a distal optical assembly 207. When operating, the DCF 206 transmits light to the distal optical assembly 207 and transmits the collected light from the distal optical assembly 207 to the PIU 210. For example, the DCF 206 transmits OCT light and collects the OCT light reflected by the sample 601. The DCF 206 also transmits excitation light and collects the fluorescence emitted by the sample 601. The distal optical assembly 207 may be equipped with a polished ball lens for lateral imaging at the tip of the DCF 206. Alternatively, the distal optical assembly 207 may be equipped with a distributed refractive index (GRIN) lens and a refractive element (grille) attached to the tip of the DCF 206. The distal optical assembly 207 shapes one or more light beams (e.g., OCT light beams, excitation light beams), directly irradiates the sample 601 with the light, and collects the light reflected, scattered, or emitted by the sample 601. The distal optical assembly 207 may also include mirrors that deflect one or more light beams radially outward. The distal optical assembly 207 is also referred to as the distal optical component 207.

[0048] At the proximal end, the curved optical imaging device 201 is connected to the PIU 210 via a connector 214. The PIU 210 can rotate the coil 203, for example, during a pullback procedure. The coil 203 transmits torque from the proximal end to the distal end. In one embodiment, the coil 203 is fixed together with or fixed to the imaging core 205 such that the distal end of the imaging core 205 and the distal optical assembly 207 rotate together with the coil 203. This allows the distal optical assembly 207 to obtain a panoramic or multi-directional view. In this way, a multi-directional view of the sample 601 can be obtained by the distal optical assembly 207 rotating while one or more light beams travel through it. Additionally, the imaging core 205 (and other parts of the curved optical imaging device 201) can move longitudinally during rotation, creating a helical scan pattern. This movement is typically achieved by pulling the distal end of the imaging core 205 back toward the proximal end. Therefore, this is called the pullback process.

[0049] The PIU210 comprises a rotary connector 211 (e.g., an optical fiber rotary joint (FORJ)), a beam coupler 212, and a pullback unit 213 (e.g., a high-precision linear stage). The PIU210 may also include a connector 214. During optical scanning, the pullback unit 213 allows adjustment or control of the position of the imaging core 205 and other parts of the curved optical imaging device 201. In one embodiment, the pullback unit 213 comprises a rotary motor and an electric linear stage. In one embodiment, the rotary connector 211 is located within the pullback unit 213. The rotary connector 211 allows the imaging core 205 to rotate relative to the PIU210, for example, to rotate inside the curved optical imaging device 201, or to rotate in conjunction with the rotation of the entire curved optical imaging device 201. During rotation, which is performed by a rotary motor, the imaging core 205 (and other parts of the curved optical imaging device 201) moves longitudinally (e.g., by an electric translational movement stage), so that light (e.g., OCT light, fluorescence) is collected in a helical scanning pattern. For example, rotation and translational movement cause the imaging core 205 to scan helically within the lumen, generating a series of near-field helical A scans of the lumen. These helical A scans can be used to create helical two-dimensional (2D) tomographic images. As another example, a series of B scans can be collected by moving the imaging core 205 longitudinally within the lumen. These B scans can be combined to form a three-dimensional (3D) image of the lumen.

[0050] The medical imaging system 10 simultaneously acquires OCT and fluorescence images from a sample 601 containing biological lumens such as blood vessels. For this purpose, OCT light from the OCT light source 301 is guided through the sample arm 32 to the sample 601 and through the reference arm 31 to the reflector 304 (e.g., a mirror). The light generates an OCT interference pattern by traveling backward along the optical path. The light from the OCT light source 301 is split into a sample beam and a reference beam (e.g., 50 / 50) by a splitter 302 (fiber splitter or beam splitter). The sample beam and reference beam are transmitted to the sample arm 32 and reference arm 31 via their respective optical fibers. Within the sample arm 32, the sample beam enters a circulator 305, proceeds through a single-mode (SM) optical fiber 321 to a fiber coupler 315, and is transmitted to the PIU 210 via a double-clad optical fiber 322. The curved optical imaging device 201 is connected to the PIU 210, which is connected to the imaging station 100. Under the control of the imaging station 100, the PIU 210 controls the imaging core 205 of the curved optical imaging device 201 to illuminate and scan the sample beam onto the sample 601. The light of the sample beam is reflected or scattered by the sample 601, and a portion of the reflected or scattered light is collected by the distal optical assembly 207 located at the distal end of the curved optical imaging device 201. The collected light is transmitted back to the PIU 210 through the double-clad optical fiber 206. The collected light (sample beam) proceeds from the PIU 210 to the fiber coupler 315 via the double-clad optical fiber 322. The fiber coupler 315 transmits a portion of the returned light to the circulator 305 via the SM optical fiber 321, and the circulator 305 leads this portion of the returned light to the coupler 306. Additionally, the fiber coupler 315 sends another portion of the reflected light to the second detector 308 via the multimode optical fiber 323.

[0051] Within the reference arm 31, the light of the reference beam enters the circulator 303 and is transmitted to the reflector 304 via the optical fiber 324. In time-domain OCT (TD-OCT) imaging, the reflector 304 is realized by a scanning mirror and an optical delay line (ODL). In frequency-domain OCT (FD-OCT) imaging, the reflector 304 is realized as a fixed mirror. The light of the reference beam reflected from the reflector 304 passes through the circulator 303 and is led to the coupler 306. In the coupler 306, the light from the reference arm 31 and the collected light from the sample arm 32 are combined. In this way, the sample beam and the reference beam are combined in the coupler 306, and the combined sample-reference beam is supplied to the first detector 307 (which may also be called the OCT detector 307). The first detector 307 detects the combined sample-reference beam and generates an interference signal according to known OCT principles.

[0052] The first detector 307 is implemented, for example, as a photodiode array, a photomultiplier tube (PMT), a multi-array camera, or other similar interference pattern detection device. In one embodiment, the first detector 307 is a balanced photodetector. The OCT detection signal output from the first detector 307 is preprocessed (digitized) by a first data acquisition electronic device (DAQ1) 401 (e.g., one or more data acquisition circuits) and transferred to the imaging station 100. The imaging station 100 performs signal processing on the OCT detection signal to generate an OCT image in a known manner. Polarization-sensitive OCT measurements can be performed using polarization-retaining (PM) optical fibers or via an in-line paddle-type polarization controller (PC).

[0053] The second detector 308 detects a portion of the sample beam transmitted from the fiber coupler 315 via the multimode optical fiber 323. The second detector 308 outputs an analog signal corresponding to the intensity of the backscattered light (backscatter signal). The backscattered signal returning from the sample 601 and detected by the second detector 308 is not an interference signal. The signal output from the second detector 308 is converted into digital data by the second data acquisition electronic device (DAQ2) 402. Using the digital signal corresponding to the intensity of the backscattered light, the distance or angle at which the light from the curved optical imaging device 201 enters the sample 601 can be calculated. Furthermore, the intensity of the backscattered light can be used as a trigger signal for the start and end of pullback and image recording operations. Therefore, the signal output from the second detector 308 and converted into digital data by the second data acquisition electronic device (DAQ2) 402 can be used directly as a trigger signal, or it can be transferred to the imaging station 100 for control processing.

[0054] The excitation light source 310 generates and emits excitation light (e.g., an excitation light beam). In one embodiment, the excitation light source 310 of the fluorescence modality emits excitation light with a central wavelength of 633 nm (emission of a second wavelength). In other embodiments, the central wavelength of the excitation light is different (e.g., 485 nm) depending on the desired application. The excitation light is guided through the optical fiber 326, the rotary connector 211, the double-clad optical fiber 206, and the distal optical component 207 to irradiate the sample 601. Upon irradiation with the excitation light, the sample 601 emits fluorescence (e.g., near-infrared autofluorescence (NIRAF), near-infrared fluorescence (NIRF)) at a broadband wavelength range higher than the wavelength of the excitation light (a third wavelength, e.g., emission from 633 to 800 nm). In one embodiment, the wavelength or wavelength range of the excitation light is one of approximately 0.633 μm, 0.633 to 0.90 μm, or 0.500 to 0.700 μm.

[0055] Fluorescence is an optical phenomenon in which a molecule absorbs photon energy, causing the immediate emission of fluorescent photons with wavelengths longer than the excitation light wavelength. In one embodiment, the fluorescence generated by sample 601 includes autofluorescence, which is endogenous fluorescence generated without the use of dyes or drugs. In another embodiment, the fluorescence generated by sample 601 includes fluorescence generated by extrinsic fluorescence from dyes or contrast agents added to the sample (e.g., during lumen clearance). The autofluorescence or fluorescence is collected by the distal optical component 207 of the curved optical imaging device 201 and returned to the PIU 210. In the PIU 210, the rotary connector 211 and the beam coupler transmit the collected fluorescence to the third detector 313 via the optical fiber 325. The fluorescence detection signal (fluorescence intensity signal) output from the third detector 313 is digitized by the second data acquisition electronic device (DAQ2) 402 and then transmitted to the imaging station 100 for image processing. In one embodiment, the OCT detection signal (having an OCT interference pattern) of the OCT modality and the fluorescence detection signal of the fluorescence modality are simultaneously transmitted to the imaging station 100.

[0056] As shown in Figure 2, the imaging station 100 comprises one or more processors 101, one or more input / output (I / O) components 102, one or more computer-readable storage media (also called memory devices) 103, and one or more buses 104. The various components of the imaging station 100 are operablely interconnected and communicate with each other via physical and logical data lines provided by one or more buses 104. Examples of buses 104 include the Universal Serial Bus (USB), IEEE 1394 bus, PCI bus, Accelerated Graphics Port (AGP) bus, Serial ATA (Serial AT Attachment (SATA)) bus, and Small Computer System Interface (SCSI) bus.

[0057] One or more processors 101 include, or are, one or more of the following: one or more central processing units (CPUs) such as microprocessors (e.g., single-core microprocessors, multi-core microprocessors), one or more graphical processing units (GPUs), one or more application-specific integrated circuits (ASICs), one or more field-programmable gate arrays (FPGAs), one or more digital signal processors (DSPs), or other electronic circuits (e.g., other integrated circuits). One or more processors 101 may also be a dedicated or general-purpose controller. One or more processors 101 is also an example of a processing unit. One or more processors 101 operate based on computer-readable instructions (e.g., in one or more programs) stored in one or more computer-readable storage media 103.

[0058] In this specification, a single computer-readable storage medium 103 includes, for example, manufactured products such as magnetic disks (e.g., floppy disks, hard disks), optical disks (CDs, DVDs, Blu-rays), magneto-optical disks, magnetic tapes, and semiconductor memories (e.g., non-volatile memory cards, flash memory, solid-state drives, SRAM, DRAM, EPROM, EEPROM). The computer-readable storage medium 103 may also be volatile memory, non-volatile memory, ROM, and RAM. Examples of one or more computer-readable storage mediums 103 include network-attached storage (NAS) devices, intranet-attached storage devices, and internet-attached storage devices. The computer-readable storage medium 103 can store computer-readable data or computer-executable instructions such as operating system (OS) programs, control program code, and processing program code. In embodiments in which one or more computer-readable storage mediums 103 include RAM, one or more processors 101 can utilize the RAM as a workspace. Furthermore, when the imaging station 100 or one or more processors 101 perform tasks such as acquiring information or data, recording information or data, generating information or data, storing information or data, manipulating information or data, or processing information or data, the information or data is stored in one or more computer-readable storage media 103. The one or more computer-readable storage media 103 are examples of storage units. The computer-readable storage media 103 are distributed among the multiple processors 101.

[0059] The input / output component 102 includes physical interfaces and communication components (e.g., GPU, network interface controller) that enable communication (wireless or wired) with other elements of the medical imaging system 10 (e.g., PIU210, OCT light source 301, first detector 307, second detector 308, third detector 313, first data acquisition electronic device (DAQ1) 401, second data acquisition electronic device (DAQ2) 402). The physical interfaces and communication components also enable communication with other computing devices (e.g., network-connected computer, PACS1400) and input or output devices including the display device 500, network devices, keyboard, mouse, printer, light pen, optical memory device, scanner, microphone, drive, joystick, control pad, etc. The input / output component 102 may include programmable logic used with programmable logic devices (PLDs), such as field-programmable gate arrays (FPGAs) and other PLDs, discrete elements, integrated circuits (e.g., application-specific integrated circuits (ASICs)), and other components including combinations of the above. The functions of the input / output component 102 are at least partially realized based on computer-executable instructions (e.g., one or more programs) recorded on one or more computer-readable storage media 103 and executed by one or more processors 101.

[0060] The functional operation of the medical imaging system 10 in Figure 2 is realized by one or more processors 101 of the imaging station 100 that execute computer-executable instructions (e.g., one or more programs) stored in one or more computer-readable storage media 103.

[0061] In one embodiment, the imaging station 100 includes a first data acquisition electronic device (DAQ1) 401 or a second data acquisition electronic device (DAQ2) 402.

[0062] Figure 4 is a schematic diagram of an exemplary embodiment of the medical imaging system 10 of Figure 1, showing details of the probe interface subsystem 300. The embodiment of the medical imaging system 10 in Figure 4 is similar to the embodiment of the medical imaging system 10 in Figure 2, except that the probe interface subsystem 300 in Figure 4 omits the second detector 308 and fiber coupler 315, and instead includes a dichroic filter 311 and a line filter 312. The dichroic filter 311 directs the collected fluorescence to a third detector 313. The line filter 312 reduces signal washout from the remaining back-reflected excitation light that reaches the line filter 312. For example, the bandwidth of the line filter 312 may be as narrow as 2 nanometers, having high filtering performance for the NIRAF excitation wavelength (e.g., 635 nm), or the bandwidth may be wider (e.g., more than 2 nm and less than 20 nm or 40 nm) to reduce the Raman signal from the optical fiber that affects the NIRAF's S / N ratio. Furthermore, the probe interface subsystem 300 shown in Figure 2 according to one embodiment includes a dichroic filter 311 or a line filter 312.

[0063] Figure 5 shows an exemplary embodiment of the user interface screen. Screen 510 includes three images 511A-511C generated based on detection data. Screen 510 also includes a control area 520. The control area 520 includes graphic control elements for activation, operation, or manipulation to input into the user interface. Furthermore, screen 510 includes an angiography image 519.

[0064] The three images 511A-511C include the first image 511A, the second image 511B, and the third image 511C. The first image 511A shows a tomographic plane of the lumen (a cross-section perpendicular to the vascular axis) generated from OCT using peripheral fluorescence detection data. The second image 511B shows a longitudinal section of the lumen (a longitudinal section parallel to the vascular axis) generated from OCT detection data. The third image 511C shows a longitudinal section of the lumen generated from fluorescence detection data. The third image 511C is an unfolded view (open view) of the lumen (showing the lumen opened in a planar manner). The first image 511A was taken from a line of sight perpendicular to the line of sight from which the second image 511B and the third image 511C were taken. Additionally, the position indicator marks 515 (also called markers) indicate where the longitudinal section of the first image 511A is located within the second image 511B and the third image 511C (for example, where the plane shown in the first image 511A is located within the second image 511B and the third image 511C).

[0065] Artifact 7 is visible in both the first image 511A and the third image 511C. In this example, the guidewire is the cause of artifact 7. Some guidewires and guidecatheters contain fluorescent materials. Such guidewires and guidecatheters are visible in the images generated from the detection data and therefore cause artifacts. Other guidewires and guidecatheters contain non-fluorescent materials. Such guidewires and guidecatheters prevent the light (OCT light and fluorescence) emitted by the curved optical imaging device 201 from reaching the lumen, resulting in the generation of artifacts (e.g., shadows) in the images generated from the detection data. These artifacts not only affect the lumen image (e.g., degradation of quality) but also affect the analysis of the imaging data. Note that guidewires and guidecatheters are examples of structures.

[0066] Figure 6 shows an exemplary embodiment of an operation flow for reducing or eliminating artifacts in images generated from fluorescence detection data. While this operation flow and other operation flows described herein are presented in a certain order, some embodiments may perform at least some of the operations in a different order. Different orders include, for example, parallel, simultaneous, overlapping, reordering, simultaneous, incremental, and alternating sequences. Furthermore, an operation flow in one embodiment may include blocks from two or more operation flows described herein. That is, in other embodiments described herein, blocks of operation flows may be omitted, added, reordered, combined, or split.

[0067] Furthermore, for the sake of simplicity, some of the operational flows described herein are performed by a single imaging station, but in some embodiments, the operational flows are performed by two or more imaging stations or one or more specially configured other computing devices.

[0068] The flow starts in block B600 and proceeds to block B610, where the imaging station 100 acquires (e.g., collects) detection data from the probe interface subsystem 300. The detection data includes fluorescence detection data. In block B620, the imaging station 100 performs initial processing of the detection data. Initial processing includes generating one or more images (including fluorescence images) based on the detection data. Initial processing also includes forming a three-dimensional (3D) data array, performing a Fast Fourier Transform (FFT), converting from polar coordinates to Cartesian coordinates, and detecting the lumen boundary for the OCT data. Furthermore, initial processing includes forming a two-dimensional (2D) data array and performing distance correction (based on lumen boundary detection of the OCT data) for the fluorescence data.

[0069] When acquiring detection data that includes both fluorescence detection data and OCT detection data (e.g., block B610), the OCT module performs 500 wavelength sweeps of OCT light for each rotation of the imaging core 205 of the catheter 201. During one wavelength scan period of the OCT light source 301, information along the beam in the depth direction is captured as optical interference and received as a high-speed optical signal. The captured optical signal is converted into an electrical signal by a high-speed photoelectric detector such as a photodiode or photomultiplier tube (e.g., first detector 307). The converted electrical signal is further converted from an analog signal to a digital signal (e.g., by DAQ1 401). Each line data along the beam is often called A-line data. This data forms a dataset along the radial lines of the tomographic image. One frame consists of one rotation of the imaging core 205, i.e., 500 radial lines of A-line data. At each of the 500 locations, one fluorescence data point is acquired by a photomultiplier tube (e.g., a third detector 313) for each rotation of the imaging core 205 of the catheter 201. The electrical signal from the photomultiplier tube is converted into a digital signal by an AD converter (e.g., DAQ2 132). These OCT and fluorescence data are collected for 400 frames of tomographic images, i.e., for 400 rotations of the imaging core 205 of the catheter.

[0070] In OCT imaging, if there are 512 data points in the depth direction, one rotation of the imaging core 205 creates a 512 × 500 dataset. 400 rotations for one pullback operation allow the medical imaging system 10 to collect a 512 × 500 × 400 OCT detection dataset. Meanwhile, fluorescence imaging collects 500 data points per rotation of the imaging core. 400 rotations per pullback collect a 500 × 400 array of fluorescence detection data. For a single fluorescence tomography image, the OCT tomography image contains 500 corresponding fluorescence detection data points.

[0071] Initial processing of the data for block B620 is performed, for example, as follows. In this example, the OCT detection data for one frame in the tomographic plane is 512 × 500. This constitutes a polar coordinate image of one OCT frame. In the same tomographic plane, the fluorescence detection data consists of a one-dimensional array of only 500 data points. By processing the OCT detection data array using Fourier transform (FFT, Fast Fourier Transform), reflectance and scattering are obtained along the beamline. For each frame, the OCT detection data is converted from polar coordinates to Cartesian coordinates. After the conversion from polar coordinates to Cartesian coordinates, the OCT detection dataset is adjusted to 1024 × 1024 data (500 tomographic images) for 500 frames. The boundary of the lumen is detected within line A, and the distance from the center to the lumen is detected. The lumen detection algorithm can be applied to the polar coordinate or Cartesian coordinate representation of the OCT detection data. The fluorescence signal is corrected using this distance, and distance-corrected fluorescence data is calculated by performing distance correction on the fluorescence detection data. In one embodiment, artifact detection is performed on the fluorescence detection data before performing distance correction.

[0072] Hereafter, fluorescence detection data that has undergone initial processing will be referred to as initial-processed fluorescence detection data.

[0073] Next, in block B630, the imaging station 100 detects artifact data in the fluorescence detection data, for example, by detecting artifact data in one or more fluorescence images (e.g., fluorescence frames). The artifact data includes detection data generated from imaging artifacts such as guidewires and guide catheters. In the following description, the detection of artifact data may also be simply referred to as artifact detection. Block B630 according to one embodiment includes the operation flow shown in Figure 16. In addition, the imaging station 100 according to one embodiment detects artifact data (i.e., detects artifacts) using a trained machine learning model (e.g., an artificial neural network).

[0074] Next, in block B640, the imaging station 100 removes or replaces artifacts in the fluorescence detection data by modifying the data corresponding to the artifacts in the fluorescence detection data. For example, the imaging station 100 removes or replaces artifacts in the fluorescence detection data as shown in Figure 7A or 7B.

[0075] Furthermore, in one embodiment, the imaging station 100 receives user input indicating the artifact detection in block B630 by the imaging station 100 and the image to be removed or replaced with the detected artifact in block B640. Exemplary embodiments of a user interface capable of receiving such input (distal and proximal limits of artifact detection) are shown in Figures 21 and 22. In some user interfaces, the user can perform such input by entering one or more image numbers (frame numbers). In one embodiment, the imaging station 100 selects the distal and proximal limits of artifact detection using an automated detection algorithm for the guide catheter in the fluorescence image, OCT image, or both the fluorescence and OCT images. The automated detection algorithm may be one or a combination of pattern matching, thresholding, pattern matching for the OCT image, or machine learning-based detection algorithms for the fluorescence or OCT image. Markers in Figures 21 and 22 can also be used on the user interface to confirm, correct, or adjust the selection based on the automated detection algorithm.

[0076] In block B650, the imaging station 100 saves the corrected fluorescence detection data. In the subsequent block B660, the imaging station 100 generates one or more fluorescence images based on the corrected fluorescence detection data and displays these one or more images on the display device 500. The flow then ends in block B670.

[0077] Figure 7A shows an exemplary embodiment of a workflow for removing or replacing artifacts in fluorescence detection data. Before the workflow begins, the imaging station 100 has acquired Ntotal tomographic images (frames). One frame is one tomographic image in OCT imaging. In fluorescence imaging, one frame is not 2D data, but just one line of data (in the tomographic image plane). The carpet image of the fluorescence modality is an open view (unfolded view).

[0078] The flow begins in block B700 and proceeds to block B710, where the imaging station 100 generates fluorescence frames based on fluorescence detection data. In block B720, the imaging station 100 sets the frame index N to 1. Each fluorescence frame consists of a line dataset with a width of 1 pixel. For example, Figure 8A shows an exemplary embodiment of a fluorescence frame set displayed in an unfolded planar shape. The unfolded planar shape is represented by matrix A(N,θ). In Figure 8A, the horizontal axis represents the frame index and the vertical axis represents the angle θ. As shown in Figure 8B, the angle θ represents the angular position of pixel P (for example, the angular position of the distal optical assembly 207 at the time of acquisition of detection data corresponding to pixel P).

[0079] In block B730, the imaging station 100 replaces each pixel value of artifact pixels in the Nth line dataset (Nth line data) with a specific pixel value. For example, in an embodiment where the imaging station 100 removes artifacts, the imaging station 100 replaces the pixel value corresponding to the artifact with zero or another value that (1) is a valid pixel value (i.e., a pixel value valid for display) and (2) indicates that no fluorescence was detected or that an invalid fluorescence signal (artifact) was detected at that pixel. Alternatively, in an embodiment where the imaging station 100 replaces artifacts, the imaging station 100 replaces the pixel value corresponding to the artifact with a value that is not a valid pixel value for display (e.g., -99, +999999, null). Zero and values ​​that are not valid pixel values ​​for display are examples of specific values. Replacing the pixel value corresponding to the artifact with a value that is not a valid pixel value for display is an example of changing artifact data to a specific value.

[0080] Next, in block B740, the imaging station 100 determines whether block B730 has been executed for all line datasets (whether N=Ntotal or not). In the above explanation, Ntotal is 400. That is, the total number of rotations in one pullback operation and the total number of line datasets are 400. If the imaging station 100 determines that block B730 has not been executed for all line datasets (B740=No), in block B750, the imaging station 100 increments N by 1, and the flow returns to block B730. If the imaging station 100 determines that block B730 has been executed for all line datasets (B740=Yes), the flow ends in block B760.

[0081] Figure 7B shows an exemplary embodiment of an operational flow for removing or replacing artifacts in fluorescence detection data. The operational flow in Figure 7B is a replacement of block B730 in Figure 7A with block B735. In block B735, for the Nth line dataset, the imaging station 100 replaces the pixel values ​​of artifact pixels and the pixel values ​​of adjacent pixels within a specific range with specific pixel values. That is, generating corrected fluorescence imaging data by the imaging station 100 involves changing fluorescence imaging data within a predetermined range (specific range) near the artifact data to specific values. The specific range may be defined as a pixel range (e.g., + / -3 pixels, 8 pixels, 10 pixels) or an angular range (e.g., + / -3°, 5°, 7°, 10°, 15°). For example, in an embodiment where the imaging station 100 removes artifacts, the imaging station 100 replaces the pixel values ​​of pixels within a specific range of the artifact pixel with zero or another value that (1) is a valid pixel value (i.e., a pixel value valid for display) and (2) indicates that no fluorescence has been detected, or that an invalid fluorescence signal (artifact) has been detected in that pixel. Alternatively, in an embodiment where the imaging station 100 replaces artifacts, the imaging station 100 replaces the pixel values ​​of pixels within a specific range of the artifact pixel with a value that is not a valid pixel value for display (e.g., -99, +999999, null). Thus, in Figure 7B, the values ​​of pixels sufficiently close to the artifact pixel are also corrected.

[0082] Figure 9 shows an exemplary embodiment of the operation flow for reducing or eliminating image artifacts generated from fluorescence detection data. In this embodiment, after artifact removal, statistical values ​​or other numerical values ​​are calculated based on the fluorescence imaging results. By doing so, this embodiment eliminates erroneous statistical analysis of blood vessels by removing artifacts that do not represent the target blood vessel signal. This embodiment saves and displays the image with artifacts removed or replaced with specific values, or saves and displays the initial image with artifacts as is. The flow starts in block B900 and blocks B610, B620, and B630 are executed. Blocks B610, B620, and B630 in Figure 9 are the same as or identical to blocks B610, B620, and B630 in Figure 6, so redundant explanations are omitted. In block B930, the imaging station 100 removes artifacts from the fluorescence detection data. For example, the imaging station 100 removes artifacts from the fluorescence detection data by executing the operation flow shown in Figure 7A or Figure 7B, using a value that (1) is a valid pixel value (i.e., a pixel value valid for display) and (2) indicates that no fluorescence has been detected, or, if block B730 is executed, in block B730, or if block B735 is executed, in block B735, an invalid fluorescence signal (artifact) has been detected as a specific pixel value in that pixel. The fluorescence detection data from which the artifacts have been removed constitutes the first corrected fluorescence detection data.

[0083] Next, in block B935, the imaging station 100 calculates one or more fluorescence results based on the first corrected fluorescence detection data. Examples of fluorescence results include the following values: the maximum value for each image (e.g., the NIRAF maximum value for each image), the sum of the images (e.g., the NIRAF image sum), the moving sum of the image sums, moving sums such as the maximum moving sum of the image mean values ​​(e.g., the NIRAF moving sum), the fluorescence count (e.g., the NIRAF count), the fluorescence index (e.g., the NIRAF index), and the maximum value of the moving sum, fluorescence count, or fluorescence index.

[0084] In the following explanation, N represents an image within a set of fluorescence images that are represented in an unfolded, planar shape by the matrix A(N,θ).

[0085] In one embodiment, for image N, the maximum fluorescence density (MPF) for each image (frame) is described by equation (1).

[0086]

number

[0087] In one embodiment, the sum FS of the fluorescence images (frames) of image N is described by equation (2).

[0088]

number

[0089] In one embodiment, for image N and the following k images, the moving sum MSFS of the sum of the images (frames) is described by equation (3).

[0090]

number

[0091] In one embodiment, the maximum MaxMSFS value of Ntotal images (N=1 to N=Ntotal) is described by equation (4).

[0092]

number

[0093] Next, in block B940, the imaging station 100 determines whether or not to replace the artifact. For example, the imaging station 100 determines whether it has received an instruction to replace the artifact or whether the settings allow for artifact replacement. If the imaging station 100 determines not to replace the artifact (B940=No), the flow proceeds to block B945. In block B945, the imaging station 100 saves the initially processed fluorescence detection data generated in block B620. In one embodiment, the imaging station 100 saves the first corrected fluorescence detection data. In block B950, the imaging station 100 generates and displays a fluorescence image based on the initially processed fluorescence detection data. The flow then ends in block B970. Alternatively, the artifact is not replaced (B940=No), and the first corrected fluorescence detection data generated in B930 is displayed.

[0094] If the imaging station 100 decides to replace artifacts (B940=Yes), the flow proceeds to block B955. In block B955, the imaging station 100 replaces artifacts in the fluorescence detection data based on the detection result of B630. For example, in block B735, the imaging station 100 replaces artifacts in the fluorescence detection data by executing the operation flow shown in Figure 7A or Figure 7B, using pixel values ​​that are not valid for display (e.g., -99, +999999, null) as specific pixel values. Artifact replacement can be performed by replacing artifacts in the first corrected fluorescence detection data. The fluorescence detection data with artifacts replaced constitutes the second corrected fluorescence detection data.

[0095] Next, in block B960, the imaging station 100 saves the second modified fluorescence detection data. In block B965, the imaging station 100 generates and displays a fluorescence image based on the second modified fluorescence detection data. The flow then ends in block B970.

[0096] In one embodiment, the imaging station 100 receives user input indicating the image to be subjected to artifact detection in block B630, removal of detected artifacts in block B930, and replacement of detected artifacts in block B955 by the imaging station 100. Exemplary embodiments of a user interface capable of receiving such input are shown in Figures 21 and 22. In one user interface, the user can perform such input by entering one or more image numbers (frame numbers). In one embodiment, the imaging station 100 saves the initial processed fluorescence detection data in block B960 or block B620, and then proceeds to artifact removal in block B930, artifact replacement in block B955, and saving the second corrected fluorescence detection data in block B960. In this embodiment, both the initial processed fluorescence detection data with artifacts removed and the initial processed fluorescence detection data without artifacts are saved for future review, processing, analysis, etc. of one or both of the datasets. For example, the imaging station 100 may perform analysis of the corrected fluorescence imaging data or the uncorrected fluorescence imaging data. Furthermore, in this embodiment, it is possible to alternately switch between displaying pre-processed fluorescence detection data with artifacts removed and pre-processed fluorescence detection data without artifacts removed.

[0097] Figure 10 shows an exemplary embodiment of a workflow for reducing or eliminating artifacts in images generated from fluorescence detection data.

[0098] Block B620 in Figure 10 is the same as or identical to block B620 in Figure 6, so redundant explanations are omitted. Also, blocks B935-B950 and B960-B970 in Figure 10 are the same as or identical to blocks B935-B950 and B960-B970 in Figure 9, so redundant explanations are omitted.

[0099] The flow starts at block B1000 and proceeds to block B1010, where imaging station 100 acquires detection data (imaging data) including OCT detection data and fluorescence detection data. The OCT detection data and fluorescence detection data are aligned. At block B1025, imaging station 100 detects artifacts in the OCT detection data, for example, as shown in Figure 11. That is, artifact data is detected based on the OCT detection data (OCT imaging data). At block B1030, imaging station 100 removes artifacts from the fluorescence detection data, for example, as shown in block B930 in Figure 9 and blocks B1700 to B1740 in Figure 17.

[0100] The flow then proceeds to block B1033, where the imaging station 100 determines whether or not to calculate fluorescence results. For example, the imaging station 100 determines whether it has received an instruction to calculate fluorescence results or whether it is set to perform fluorescence result calculation. If the imaging station decides to calculate fluorescence results (B1033=Yes), the flow proceeds to block B935 and then block B940. If the imaging station decides not to calculate fluorescence results (B1033=No), the flow proceeds to block B940.

[0101] In block B1055, the imaging station 100 replaces artifacts in the fluorescence detection data, for example, as shown in block B955 in Figure 9 and blocks B1710 to B1840 in Figure 18.

[0102] In one embodiment, the imaging station 100 receives user input indicating the image to be subjected to artifact detection in block B1025, removal of detected artifacts in block B1030, and replacement of detected artifacts in block B1055 by the imaging station 100. Exemplary embodiments of a user interface capable of receiving such input are shown in Figures 21 and 22. In one user interface, the user can perform such input by entering one or more image numbers (frame numbers).

[0103] Figure 11 shows an exemplary embodiment of the operation flow for detecting artifacts in OCT detection data. The flow starts in block 1100 and proceeds to block B1105, where the imaging station 100 generates Ntotal (where Ntotal is a positive integer) OCT frames based on the OCT detection data. Next, in block B1110, the imaging station 100 sets the frame index N to 1. Then, in block B1115, the imaging station 100 selects frame N.

[0104] In block B1120, the imaging station 100 determines the sum of pixel values ​​for each angle θ within frame N. The sum of pixel values ​​at angle θ is the sum of pixel values ​​along a radial path from the center to the edge of the frame, where the angle of the path is angle θ. For example, Figure 12A shows an exemplary embodiment of an OCT frame. The line R indicates the reference direction of the angle (e.g., the polar axis). The sum of pixel values ​​at angle θ1 is the sum of pixel values ​​of pixels along a radial path P from the center C to the edge of the frame, where the radial direction and the reference direction (indicated by the line R) form an angle θ1. The OCT frame may also have a different format than that shown in Figure 12A. For example, Figure 12B shows the OCT frame of Figure 12A in a different coordinate system. In Figure 12B, the pixels are arranged such that the lower left corner indicates an angle of 0° and a radial distance R of zero. The vertical axis indicates the radial distance R, and the horizontal axis indicates the angle θ. Also, Figure 13A shows the sum of pixel values ​​in the OCT frame of Figure 12A. In Figure 13A, the horizontal axis represents the angle θ, and the vertical axis represents the sum of angles θ, S(θ). Note that the sum of pixel values ​​in the OCT frame is an example of OCT imaging values.

[0105] Next, in block B1125, the imaging station 100 identifies a step-down angle θ_Lo in which the sum decreases rapidly. The step-down angle θ_Lo is defined as follows: (i) (1) The absolute difference between the sum of angle θ_Lo and (2) the sum of angles preceding angle θ_Lo and within a specific range of angle θ_Lo (e.g., 1°, 3°, 5°, 8°) is greater than the step-down threshold, and the sum of angles preceding angle θ_Lo is greater than the sum of angle θ_Lo (i.e., there is a decrease in value from angles preceding angle θ_Lo to angle θ_Lo). (ii) (1) The absolute difference between the sum of angle θ_Lo and (2) the sum of angles following angle θ_Lo and within a specific range of angle θ_Lo (e.g., 1°, 3°, 5°, 8°) is greater than the step-down threshold, and the sum of angles following angle θ_Lo is less than the sum of angle θ_Lo (i.e., there is a decrease in value from angle θ_Lo to angles following angle θ_Lo). The step-down threshold is an example of a first threshold. The step-down angle θ_Lo is an example of a first angular position. That is, the imaging station 100 detects a first angular position that includes an OCT imaging value that changes beyond the first threshold.

[0106] For example, Figure 13B shows the difference between the sum of angles in the vicinity of the angle shown in Figure 13A and the sum in Figure 13A. The vertical axis in Figure 13B shows the difference between the sum of each angle and the sum of the previous angle. That is, for angle θ, the vertical axis shows S(θ)-S(θ-1) (shown in Figure 13A). In Figure 13B, the step-down angle θ_Lo is 201° (an angle showing a sharp decrease), and the graph in Figure 13B has a peak at 201°. Also, in Figures 12A and 12B, 201° is marked.

[0107] Next, in block B1130, the imaging station 100 identifies a step-up angle θ_High, which is the angle at which the sum increases sharply. The step-up angle θ_High is defined as follows: (i) (1) The absolute difference between the sum of angle θ_High and (2) the sum of angles preceding angle θ_High and within a specific range of angle θ_High (e.g., 1°, 3°, 5°, 8°) is greater than the step-up threshold, and the sum of angles preceding angle θ_High is less than the sum of angle θ_High (i.e., there is an increase in value from the angles preceding angle θ_High to angle θ_High). (ii) (1) The absolute difference between the sum of angle θ_High and (2) the sum of angles following angle θ_High and within a specific range of angle θ_High (e.g., 1°, 3°, 5°, 8°) is greater than the step-up threshold, and the sum of angles following angle θ_High is greater than the sum of angle θ_High (i.e., there is an increase in value from angle θ_High to the angles following angle θ_High). The step-up threshold is an example of a second threshold. The step-up angle θ_High is an example of a second angular position. That is, the imaging station 100 detects a second angular position that includes an OCT imaging value that changes beyond the second threshold.

[0108] For example, in Figures 13A and 13B, the step-up angle θ_High is 228° (an angle indicating a rapid increase), and the graph in Figure 13B has a peak at 228°. Also, in Figures 12A and 12B, 228° is marked. Artifacts are observed from 201° to 228°.

[0109] Furthermore, if there are two or more step-down angles θ_Lo or two or more step-up angles θ_High, the step-down angle θ_Lo or step-up angle θ_High is the one closest to the angle that maximizes the sum of the two angles.

[0110] Next, in block B1135, the imaging station 100 determines whether the step-down angle θ_Lo and the step-up angle θ_High are within a specific angular range θmax (i.e., whether |θ_High-θ_Lo|≦θmax is satisfied). For example, in one embodiment, θmax is 10°, 20°, 30°, or 40°. If the step-down angle θ_Lo and the step-up angle θ_High are within the specific angular range θmax (B1135=Yes), the flow proceeds to block B1140, where the imaging station 100 saves the step-down angle θ_Lo and the step-up angle θ_High for frame N in association with frame N. The flow then proceeds to block B1155.

[0111] If the step-down angle θ_Lo and the step-up angle θ_High are not within a specific angular range θmax (B1135=No), the flow proceeds to block B1145, and the imaging station 100 discards the step-down angle θ_Lo and the step-up angle θ_High for frame N. The flow then proceeds to block B1150. In another embodiment, if the step-down angle θ_Lo and the step-up angle θ_High are not within a specific angular range θmax, the imaging station 100 expands the specific angular range θmax and determines whether the step-down angle θ_Lo and the step-up angle θ_High are within the expanded angular range θmax. If the step-down angle θ_Lo and the step-up angle θ_High are within the expanded angular range θmax, the flow proceeds to block B1140. If the step-down angle θ_Lo and the step-up angle θ_High are not within the expanded angular range θmax, the flow proceeds to block B1145.

[0112] In block B1150, the imaging station 100 determines whether to execute block B1130 for different step - down angles θ_Lo or different step - up angles θ_High. In one embodiment, if block B1135 has not been executed for all possible combinations of the step - down angle θ_Lo and the step - up angle θ_High within frame N, the imaging station 100 decides to execute block B1135 again. For example, if frame N includes two step - down angles θ_Lo and two step - up angles, the imaging station 100 executes block B1135 four times while changing the combination of the step - down angle θ_Lo and the step - up angle θ_High each time. If the imaging station 100 decides to execute block B1130 for different step - down angles θ_Lo or different step - up angles θ_High (B1150 = Yes), the flow returns to block B1125. If the imaging station 100 decides not to execute block B1130 for different step - down angles θ_Lo or different step - up angles θ_High (B1150 = No), the flow proceeds to block B1155.

[0113] In block B1155, the imaging station 100 determines whether blocks B1120 - B1150 have been executed for all frames (whether N = Ntotal). If the imaging station 100 determines that blocks B1120 - B1150 have not been executed for all frames (N < Ntotal) (B1155 = No), the flow proceeds to block B1160. In block B1160, the imaging station 100 increments N by 1, and the flow returns to block B1120. If the imaging station 100 determines that blocks B1120 - B1150 have been executed for all frames (N = Ntotal) (B1155 = Yes), the flow ends at block B1165.

[0114] Furthermore, guidewires and guide catheters can generate artifacts that appear along their centerline parallel to their vertical axis. In a graph showing the difference between the sums of angles near the angle in question (for example, the graph in Figure 13B), such artifacts can cause another peak to appear between the peaks of the step-down angle θ_Lo and the step-up angle θ_High. Therefore, in one embodiment, the imaging station 100 determines in block B1135 whether such a peak exists between the step-down angle θ_Lo and the step-up angle θ_High. If such a peak exists and the step-down angle θ_Lo and the step-up angle θ_High are within θmax, the flow proceeds to block B1140. If such a peak does not exist and the step-down angle θ_Lo and the step-up angle θ_High are not within θmax, the flow proceeds to block B1145.

[0115] As another example, Figure 14A shows an exemplary embodiment of an OCT frame, and Figure 14B shows the OCT frame of Figure 14A in a different coordinate system. In Figure 14B, the pixels are arranged such that the lower left corner indicates an angle of 0° and a radial distance R of zero. Also, Figure 15A shows the sum of the pixel values ​​in the OCT frame of Figure 14A. Figure 15B shows the difference between the sum of angles in the vicinity of the angle shown in Figure 15A and the sum in Figure 15A. In Figures 15A and 15B, the step-down angle θ_Lo (angle indicating a rapid decrease) is 119°, and 119° is marked in Figures 14A and 14B. The step-up angle θ_High (angle indicating a rapid increase) is 156°, and is marked in Figures 14A and 14B. Artifacts are observed from 119° to 156°. That is, the imaging station 100 defines the detected range between the first angular position and the second angular position as artifact data.

[0116] Figure 16 shows an exemplary embodiment of the operational flow for detecting artifacts in fluorescence detection data. The flow starts at block B1600 and proceeds to block B1610, where the imaging station 100 generates one or more fluorescence images based on the fluorescence detection data.

[0117] Next, in block B1615, the imaging station 100 obtains (e.g., receives, acquires, reads) the identifier of the guidewire or guidecatheter. The identifier indicates a specific model or type of the guidewire or guidecatheter. The imaging station 100 receives the identifier via user input or reads the identifier from memory (e.g., memory that stores settings indicating the identifier).

[0118] In block B1620, the imaging station 100 acquires a mesh pattern corresponding to an identifier. For example, the imaging station 100 reads the mesh pattern from a storage device or another computing device using the identifier. Certain guidewires or guide catheters appear as mesh patterns in the fluorescence image.

[0119] In block B1625, the imaging station 100 identifies a region containing a mesh-like pattern within the fluorescence image. In block B1630, the imaging station 100 records the region containing the mesh-like pattern, for example, by recording information identifying the region containing the mesh-like pattern in a storage device. The flow then ends in block B1635.

[0120] Figure 17 shows an exemplary embodiment of the workflow for removing artifacts from a fluorescence image. The workflow begins in block B1700 and proceeds to block B1710, where the imaging station 100 sets frame index N to 1. In block B1715, the imaging station 100 selects fluorescence frame N. Next, in block B1720, the imaging station 100 obtains a step-down angle θ_Lo and a step-up angle θ_High for the OCT frame corresponding to fluorescence frame N. Since the OCT frame corresponding to fluorescence frame N is an OCT frame aligned with fluorescence frame N, the corresponding OCT frame and fluorescence frame N exhibit the same features at the same location (e.g., portion of sample 601, portion of the guidewire).

[0121] In block B1725, the imaging station 100 sets the value of a pixel located between the step-down angle θ_Lo and the step-up angle θ_High within the fluorescence frame N to zero, or to another value indicating that (1) it is a valid pixel value (i.e., a pixel value valid for display) and (2) no fluorescence has been detected, or that an invalid fluorescence signal (artifact) has been detected in that pixel. The imaging station 100 may also set the value of a pixel to zero, or to another value indicating that (1) it is a valid pixel value (i.e., a pixel value valid for display) and (2) no fluorescence has been detected, or that an invalid fluorescence signal (artifact) has been detected in that pixel, if it satisfies at least one of the following criteria. For example, one criterion is that the pixel is located within a predetermined tolerance range (e.g., ±5°, ±10°) of the step-down angle θ_Lo or the step-up angle θ_High. Another criterion is that the pixel is located within a predetermined angular range (e.g., 25°, 30°) of the intermediate angle between the step-down angle θ_Lo and the step-up angle θ_High (for example, if the step-down angle θ_Lo is 60° and the step-up angle θ_High is 90°, the intermediate angle is 75°).

[0122] The flow proceeds to block B1730, where imaging station 100 determines whether blocks B1720-B1725 have been performed for all fluorescence frames (whether N=Ntotal, where Ntotal is the total number of fluorescence frames). If blocks B1720-B1725 have not been performed for all fluorescence frames (B1730=No), in block B1735, imaging station 100 increments N by 1, and the flow returns to block B1715.

[0123] If blocks B1720-B1725 have been executed for all fluorescence frames (B1730=Yes), the flow terminates at block B1740.

[0124] Figure 18 shows an exemplary embodiment of the operation flow for replacing artifacts in a fluorescence image. The flow begins in block B1800. Blocks B1710–B1720 and B1730–B1735 in Figure 18 are similar to or identical to blocks B1710–B1720 and B1730–B1735 in Figure 17.

[0125] In block B1825, with respect to the fluorescence frame N, the imaging station 100 sets the value of a pixel that satisfies at least one of the following criteria to a value that is not a valid pixel value (e.g., -99, null). One criterion is that the pixel is located between the step-down angle θ_Lo and the step-up angle θ_High. Another criterion is that the pixel is located within a predetermined tolerance range of the step-down angle θ_Lo or the step-up angle θ_High (e.g., ±5°, ±10°). Yet another criterion is that the pixel is located within a predetermined angular range (e.g., 25°, 30°) of the intermediate angle between the step-down angle θ_Lo and the step-up angle θ_High. The predetermined angular range is calculated, for example, from the size of the guidewire. That is, artifact data is detected based on information about structures shown in the fluorescence imaging data. Figures 25A-25B show the calculation of the guidewire angular range. Figure 25A is a partial view of the OCT frame because the region of interest in the OCT frame is magnified. For each frame, the angular range can be calculated more accurately based on the size of the guidewire and the distance from the guidewire to the center of the frame. The distance d to the guidewire surface can be obtained from the OCT image. When the radius of the guidewire is r, the angular range θ of the guidewire is described or calculated by the following equation (5).

[0126]

number

[0127] The distance d to the guidewire is between θ_Lo and θ_High, i.e., 201 in Figure 12B. o and 228 oThis is determined as the minimum distance to a bright line or high-luminosity boundary within the angular range. From this calculation, 201 o and 228 o The average value, i.e., 214.5 o A theoretically accurate angular range centered on this point can be determined. This calculation of the angular range can be used as a cross-check against the determined values ​​of θ_Lo and θ_High.

[0128] Once blocks B1720 and B1825 have been executed for all fluorescence frames (B1730=Yes), the flow terminates at block B1840.

[0129] Figure 19 shows an exemplary embodiment of the operation flow for displaying a fluorescence image with artifacts replaced.

[0130] The flow starts in block B1900, and in block B1910, the imaging station 100 acquires one or more fluorescence images (e.g., fluorescence frames) with artifacts replaced. As described above, artifacts are replaced by changing the values ​​of the pixels corresponding to the artifacts to invalid values. Next, in block B1915, the imaging station 100 replaces these invalid values ​​with values ​​corresponding to predetermined colors, such as colors that do not normally appear in the fluorescence image (e.g., frames). That is, in the corrected fluorescence image, the areas corresponding to the artifact data are displayed in the predetermined color. This makes it easier for the observer to identify areas of the fluorescence image that do not show valid fluorescence information for reasons such as, for example, that fluorescence detection data was not collected, is invalid, or does not represent sample 601. The output of block B1910 is one or more corrected fluorescence images. Next, in block B1920, the imaging station 100 generates a display containing one or more corrected fluorescence images (e.g., fluorescence frames), and the flow ends in block B1925.

[0131] For example, Figure 20A shows a fluorescence frame containing artifacts. In Figures 20A and 20B, the vertical axis is the angle θ, and the horizontal axis is the frame number N. Each frame is a row of pixels with a width of one pixel or several pixels. The fluorescence frame includes a fluorescence region 6. Fluorescence region 6 is the region where fluorescence is detected, and the pixel value indicates the detection of fluorescence. The fluorescence frame also includes a guidewire artifact 7. The pixel value corresponding to the guidewire artifact 7 has been replaced with an invalid value. Figure 20B shows a display of the fluorescence frame with the pixel value corresponding to the guidewire artifact 7 replaced with an invalid value. When displaying the fluorescence frame, the value of the replaced pixel 8 is changed to a value of a predetermined color (e.g., red, pink, orange), as shown, for example, in block B1915 of Figure 19. Furthermore, the value representing the displayed color does not have to be the same as the value of the replaced pixel, nor does it have to be the same as the specific pixel value used during artifact removal or replacement. For example, if a particular pixel value is -99 (not a valid pixel value for display), the value representing the displayed color does not have to be the same as -99. This allows the observer to easily identify pixels that have had their values ​​replaced, which represent artifacts.

[0132] Figure 21 shows an exemplary embodiment of a user interface in which the user can select a region in which artifact detection is performed. The user interface 514 displays a fluorescence frame 513. The fluorescence frame 513 contains an artifact 7, including a fluorescence region 6, which is caused by the guide catheter. The user interface 514 has a marker 515. The marker 515 indicates a boundary that serves as the start or end point for artifact detection. The user can also move the marker 515 to adjust where artifact detection is performed. The imaging station 100 performs artifact detection and artifact removal, or artifact detection and artifact replacement, in fluorescence frames adjacent to the marker 515, for example, as described in Figures 6, 7A, 7B, 9, 10, 11, or 16. Also, the frame number of a frame close to the marker 515 is greater than the frame number of a frame at the location of the marker 515.

[0133] Figure 22 shows an exemplary embodiment of a user interface in which the user can select an area in which artifact detection is performed. The user interface 514 displays a fluorescence frame 513. The fluorescence frame 513 contains an artifact 7, including a fluorescence region 6, which is caused by the guide catheter. The user interface 514 has a proximal marker 516 and a distal marker 517. The user moves the proximal marker 516 and the distal marker 517 to adjust the area in which artifact detection is performed. The imaging station 100 performs artifact detection and artifact removal, or artifact detection and artifact replacement, in fluorescence frames close to the proximal marker 516 and fluorescence frames far from the distal marker 517, for example, as described in Figures 6, 7, 9, 10, 11, or 16. Thus, in such embodiments, the imaging station does not perform artifact detection, artifact removal, or artifact replacement on fluorescence frames located between the proximal marker 516 and the distal marker 517. Furthermore, the frame numbers of frames close to the proximal marker 516 are greater than the frame numbers of frames located at the position of the proximal marker 516. The frame numbers of frames far from the distal marker 517 are smaller than the frame numbers of frames located at the position of the distal marker 517. The imaging station 100 identifies fluorescence frames close to the proximal marker 516 and fluorescence frames far from the distal marker 517 as artifact data. That is, the imaging station 100 acquires selected distal frames from the fluorescence imaging data and identifies fluorescence imaging data frames with frame numbers smaller than the frame number of the distal frame which is artifact data. The imaging station 100 also acquires selected proximal frames from the fluorescence imaging data and identifies fluorescence imaging data frames with frame numbers larger than the frame number of the proximal frame which is artifact data.

[0134] Figure 23 is a schematic diagram of an exemplary embodiment of an imaging station. The imaging station 100 comprises one or more processors 101, one or more computer-readable storage media 103, one or more input / output (I / O) components 102, and a bus 104.

[0135] One or more processors 101 are or include one or more central processing units (CPUs) such as microprocessors (e.g., single-core microprocessors, multi-core microprocessors), one or more graphical processing units (GPUs), one or more application-specific integrated circuits (ASICs), one or more field-programmable gate arrays (FPGAs), one or more digital signal processors (DSPs), or other electronic circuits (e.g., other integrated circuits). One or more processors 101 may also be a dedicated or general-purpose controller. One or more processors 101 may include multiple processors, including (i) processors included in the imaging station 100, and (ii) processors that communicate with the imaging station 100 but are not included in the imaging station 100. One or more processors 101 are also an example of a processing unit.

[0136] One or more processors 101 operate according to computer-readable instructions (e.g., one or more programs) stored in one or more computer-readable storage media 103. In this specification, one computer-readable storage media 103 includes manufactured products such as magnetic disks (e.g., floppy disks, hard disks), optical disks (e.g., CDs, DVDs, Blu-rays), magneto-optical disks, magnetic tapes, and semiconductor memories (e.g., non-volatile memory cards, flash memory, solid-state drives, SRAM, DRAM, EPROM, EEPROM). Therefore, the computer-readable storage media 103 is not merely a temporary propagation signal. Examples of one or more computer-readable storage media 103 include network-attached storage (NAS) devices, intranet-attached storage devices, and internet-attached storage devices. One or more computer-readable storage media 103, which may include both ROM and RAM, are capable of storing computer-readable data and computer-executable instructions. Furthermore, in embodiments where one or more computer-readable storage media 103 include RAM, one or more processors 101 can utilize the RAM as a workspace. Furthermore, when the imaging station 100 or one or more processors 101 perform tasks such as acquiring information or data, recording information or data, generating information or data, storing information or data, manipulating information or data, or processing information or data, the information or data is stored in one or more computer-readable storage media 103. The one or more computer-readable storage media 103 are examples of storage units. The computer-readable storage media 103 are distributed among the multiple processors 101.

[0137] The imaging station 100 further comprises an input / output component 102. The input / output component 102 includes other components of the medical imaging system 10 (e.g., curved optical imaging device 201, probe interface subsystem 300, display device 500), other computing devices (e.g., network-attached computer, PACS 1400), and physical interfaces and communication components (e.g., GPU, network interface controller) that enable communication (wireless or wired) with input or output devices including the display device 500, keyboard, mouse, printer, light pen, optical memory device, scanner, microphone, drive, joystick, control pad, etc.

[0138] Furthermore, the hardware components of the imaging station 100 communicate via one or more buses 104 or other electronic connections. Examples of buses 104 include the Universal Serial Bus (USB), IEEE 1394 bus, PCI bus, Accelerated Graphics Port (AGP) bus, Serial ATA (Serial AT Attachment (SATA)) bus, and Small Computer System Interface (SCSI) bus.

[0139] Furthermore, the imaging station 100 includes a data acquisition module 1031, an artifact detection module 1032, a data correction module 1033, a fluorescence result calculation module 1034, and a communication module 1035. In this specification, a module includes logic, computer-readable data, or computer-executable instructions. In the embodiment shown in Figure 23, each module is implemented as software (e.g., Assembly, C, C++, C#, Java®, JavaScript®, BASIC, Perl, Visual Basic, Python, PHP, etc.). However, in one embodiment, each module is implemented as hardware (e.g., a customized circuit) or a combination of software and hardware. If a module is implemented at least partially in software, the software can be stored in the storage device 103. Also in one embodiment, the imaging station 100 has more or fewer modules, and modules are integrated into a smaller number of modules or divided into a larger number of modules. Furthermore, these modules each utilize (e.g., call) other modules. The imaging station 100 also includes a data repository 1036 for storing information, detection data, and images.

[0140] The data acquisition module 1031 includes instructions to an applicable component of the imaging station 100 (e.g., one or more processors 101, storage devices 103, input / output components 102) to communicate with and control other elements of the medical imaging system 10, such as the probe interface subsystem 300, and to collect detection data (including fluorescence detection data, which may include OCT detection data) from the probe interface subsystem 300. For example, a data acquisition module 1031 according to one embodiment includes instructions to an applicable component of the imaging station 100 to control an applicable component of the medical imaging system 10 to perform at least some of the operations described in blocks B610-B620 of Figure 6, blocks B610-B620 of Figure 9, and B1010 and B620 of Figure 10. An applicable component of the imaging station 100 operating according to the data acquisition module 1031 implements an example of a data acquisition unit.

[0141] The artifact detection module 1032 includes instructions for applicable components of the imaging station 100 (e.g., one or more processors 101, storage devices 103, input / output components 102) to detect artifacts in the fluorescence detection data or OCT detection data. For example, an artifact detection module 1032 according to one embodiment includes instructions for applicable components of the imaging station 100 to perform at least some of the operations described in block B630 of Figure 6, block B630 of Figure 9, B1025 of Figure 10, blocks B1100-B1165 of Figure 11, and blocks B1600-B1635 of Figure 16. Applicable components of the imaging station 100 operating according to the artifact detection module 1032 implement an example of an artifact detection unit.

[0142] The data correction module 1033 includes instructions for applicable components of the imaging station 100 (e.g., one or more processors 101, storage devices 103, input / output components 102) to remove or replace artifacts in the fluorescence detection data. For example, the data correction module 1033 according to one embodiment includes instructions for applicable components of the imaging station 100 to perform at least some of the operations described in blocks B640-B650 of Figure 6, blocks B700-B760 of Figure 7A, blocks B700-B760 of Figure 7B, blocks B930, B940, B945, B955, B960 of Figure 9, blocks B1030, B940, B945, B1055, B960 of Figure 10, blocks B1700-B1740 of Figure 17, and blocks B1800-B1840 of Figure 18. An applicable component of the imaging station 100 operating according to the data correction module 1033 implements an example of a data correction unit.

[0143] The fluorescence result calculation module 1034 includes instructions for applicable components of the imaging station 100 (e.g., one or more processors 101, storage devices 103, input / output components 102) to calculate fluorescence results based on artifact-free fluorescence detection data. For example, the fluorescence result calculation module 1034 according to one embodiment includes instructions for applicable components of the imaging station 100 to perform at least some of the operations described in block B935 of Figure 9 and blocks B1033 and B935 of Figure 10. Applicable components of the imaging station 100 operating according to the fluorescence result calculation module 1034 implement an example of a fluorescence result calculation unit.

[0144] The communication module 1035 includes instructions to the applicable components of the imaging station 100 (e.g., one or more processors 101, storage devices 103, input / output components 102) to communicate with input devices, output devices, and one or more other computing devices (e.g., PACS 1400). The communication includes one or more of the following: displaying images and user interfaces on the display device 500, and receiving input from input devices (e.g., selecting marker positions such as marker 515 in Figure 21, and proximal marker 516 and distal marker 517 in Figure 22). For example, the communication module 1035 according to one embodiment includes instructions to the applicable components of the imaging station 100 to perform at least some of the operations described in block B660 in Figure 6, blocks B950 and B965 in Figure 9, blocks B950 and B965 in Figure 10, and blocks B1900-B1925 in Figure 19. An example of a communication unit is implemented by an applicable component of the imaging station 100 operating according to the communication module 1035.

[0145] Figure 24A shows an example of a series of tomographic OCT frames of the lumen. The series of frames 1520 includes multiple tomographic OCT frames 521. Because OCT imaging is a modality that can image structures beneath the surface of sample 601, the OCT detection data is three-dimensional. For example, the OCT detection data can be defined in a roughly cylindrical three-dimensional space. Thus, the OCT frames 521 (tomographic OCT images) are collectively defined in three-dimensional space (as shown in Figure 24A). Therefore, the position of a pixel P is defined by the OCT frame 521 containing the pixel P (or, more generally, by its position on the vertical axis), the angle θp (shown as the angle relative to the reference angle 0° in Figure 24A), and the distance rp from the reference position. Thus, multiple pixels are aligned along the angle θp (though at different distances), and multiple pixels are located at a distance rp (though at different angles) from the reference position.

[0146] Figure 24B shows an example of a longitudinal section of the lumen generated from OCT detection data. Longitudinal section 525 is a cross-sectional view of the lumen along the plane indicated by line AA in Figure 24A. The angle of the plane relative to the reference angle is θv. In Figure 24, the angle θv is 90°. However, longitudinal section 525 may be a cross-sectional view along a plane at a different angle (e.g., by user input of a different angle θv).

[0147] Figure 24C shows an example of a series of fluorescence frames in a lumen. The series of frames 530 contains multiple fluorescence frames 531. Since fluorescence detection data is typically two-dimensional, each fluorescence frame 531 can be considered a two-dimensional image wound in a cylindrical shape (the height of the cylinder is only a few pixels wide). Thus, the position of a pixel P is defined by the fluorescence frame 531 containing the pixel P (or, more generally, by its position on the vertical axis) and the angle θp (shown as the angle relative to the reference angle 0° in Figure 24C). However, since there are no two pixels with the same angle θp within the nth fluorescence frame 531, the position of a pixel along angle θp is not further defined by distance. Furthermore, in a carpet-like display, the fluorescence frames 531 may be unfolded into a planar frame, for example, as in the third image 511C in Figure 5.

[0148] In a carpet-like display, the dataset can be represented in various arrangements. In one embodiment (for example, an embodiment where there are 400 frames per pullback and 500 data points per frame (or one rotation of the imaging core 205 of the catheter 201)), the fluorescence data can be represented as an m x n matrix F. The row numbers correspond to the frame numbers, and the column numbers correspond to the number of detection points (pixels) in one frame (one tomographic image or one rotation of the imaging core 205 of the catheter 201). Its elements are represented by the f in equation (6) below. i,j It is represented by [this].

[0149]

number

[0150] In this embodiment, the artifact is fi,j When identified on the corresponding point (pixel), the value of that point (pixel) is replaced with a specific pixel value such as -99 or zero. The signal of that point (pixel) can be removed by using N / A or null for this fluorescence data matrix F in the memory, as long as the memory and the imaging station 100 can process the input related thereto.

[0151] Also, in one embodiment, the fluorescence data is a data list as follows.

[0152]

Number

[0153] In such a data representation, the artifact data is removed by removing one of the (i, j, f ij ) data. Or, the replacement of the artifact data is performed by replacing the value of f ij with a specific pixel value such as -99 or zero.

[0154] At least a part of the above-described apparatus, system, and method can be at least partially implemented by providing one or more computer-readable media containing computer-executable instructions for realizing the above-described operations to one or more arithmetic units that read and execute the computer-executable instructions. The system or apparatus executes the computer-executable instructions to perform the operations of the above-described embodiments. Also, at least a part of the operations of the above-described embodiments may be performed by an operating system on one or more systems or apparatuses.

[0155] Also, in one embodiment, one or more functional units are used to realize the above-described apparatus, system, and method. The functional unit is realized only by hardware (e.g., a customized circuit) or a combination of software and hardware (e.g., a microprocessor that executes software).

[0156] This specification provides specific details for a full understanding of the embodiments disclosed. However, to avoid making this disclosure unnecessarily redundant, known methods, procedures, components, and circuits may not be described in detail.

[0157] Furthermore, when it is indicated that a member (e.g., an element, part, component) is "on top of," "against," "connected to," or "joined" another member, that member may be directly "on top of," "against," or "connected to" another member, but there may be an intervening member between the member and the other member. On the other hand, when it is indicated that a member is "directly on top of," "directly against," or "directly connected to" another member, there is no intervening member between the member and the other member.

[0158] Furthermore, terms such as "equipped with," "possess," "include," and "contain" are considered open terms unless otherwise specified. These terms in this specification indicate the existence of described features, integers, steps, actions, elements, materials, components, etc., but do not exclude the existence or addition of features, integers, steps, actions, elements, materials, components, etc. that are not explicitly stated.

[0159] All features and all steps of methods and processes disclosed herein, including the claims, abstract and drawings, are combinatorial and can be combined, except for any mutually exclusive combinations of features or steps that constitute at least a portion of such features or steps.

[0160] The drawings illustrate several possible configurations and techniques, but are not necessarily drawn to scale. Certain features may be exaggerated, omitted, or partially divided for the purpose of better describing and illustrating certain aspects of this disclosure. The description herein is not intended to be exhaustive, nor is it intended to limit or restrict the claims to the exact forms and configurations disclosed in the illustrated and detailed descriptions.

[0161] While several embodiments have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0162] 6. Fluorescent regions 7. Artifacts (Guidewire Artifacts) 10 Medical imaging systems 31 Reference Arm 32 Sample Arms 100 Imaging Stations 101 Processors 102 Input / Output (I / O) Components 103 Computer-readable storage medium (storage device) 104 Bus 201 Catheter (Bending Optical Imaging Device) 202 Flexible cylindrical body 203 Coil 204 Protector 205 Imaging Core 206 Double-clad optical fiber (DCF) 207 Distal Optical Components (Distal Optical Assemblies) 210 Patient Interface Unit (PIU) 211 Rotary connection section 212 Beam Coupler 213 Pullback Unit 214 Connector 300 Probe Interface Subsystem 301 OCT light source 302 Splitter 303 Circulator (First Circulator) 304 Reflector 305 Circulator (Second Circulator) 306 Combiner 307 OCT detector (first detector) 308 Second detector 309 Detection Unit 310 Excitation light source 311 Dichroic Filter 312 line filter 313 Fluorescence detector (third detector) 315 Fiber Coupler 321 Single-mode (SM) fiber optic cable 322 Double-clad optical fiber 323 Multimode Optical Fiber 324,325,326 optical fibers 400 Data Acquisition Units (DAQ) 401 First Data Acquisition Electronic Device (DAQ1) 402 Second Data Acquisition Electronic Device (DAQ2) 500 display device 510 screen 511A Image 1 511B Second image 511C Third image 513,531 Fluorescent Frames 514 User Interface 515 Position Indicator Marker 516 Proximal Markers 517 Distal markers 519 Angiography image 520 Control area 521 OCT frame (fault OCT frame) 525 Longitudinal section 530,1520 frames 601 samples 1031 Data Acquisition Module 1032 Artifact Detection Module 1033 Data Correction Module 1034 Fluorescence Result Calculation Module 1035 Communication Module 1036 Data Repository 1400 Image Archiving and Communication System (PACS)

Claims

1. Acquire imaging data that includes at least fluorescence imaging data. To detect artifact data in the aforementioned fluorescence imaging data, By removing the artifact data or by changing the artifact data in the fluorescence imaging data to a specific value, corrected fluorescence imaging data is generated, and To generate an image based on the corrected fluorescence imaging data, A medical imaging method comprising [a specific feature / feature].

2. The aforementioned imaging data further includes optical coherence tomography (OCT) imaging data, The artifact data is detected based on the OCT imaging data. The medical imaging method according to claim 1.

3. Detecting the aforementioned artifact data means To detect a first angular position that includes an OCT imaging value that changes beyond a first threshold, Detecting a second angular position that includes an OCT imaging value that changes beyond a second threshold, and This includes defining the detected range between the first angular position and the second angular position as the artifact data, The medical imaging method according to claim 2.

4. The artifact data is detected based on information about the structure shown in the fluorescence imaging data. The medical imaging method according to claim 1.

5. The aforementioned structure is a guide wire or a guide catheter. The medical imaging method according to claim 4.

6. Generating the corrected fluorescence imaging data further includes changing the fluorescence imaging data within a predetermined range near the artifact data to the specific value. The medical imaging method according to claim 1.

7. The aforementioned specific value is zero or null. The medical imaging method according to claim 1.

8. The region of the aforementioned image corresponding to the artifact data is displayed in a predetermined color. The medical imaging method according to claim 1.

9. To perform the analysis of the corrected fluorescence imaging data, The medical imaging method according to claim 1, further comprising the above.

10. To obtain a selected distal frame from the fluorescence imaging data, and to identify the frame of the fluorescence imaging data with a frame number smaller than the frame number of the distal frame which is artifact data, or, To obtain a selected proximal frame from the fluorescence imaging data, and to identify the frame of the fluorescence imaging data with a frame number greater than the frame number of the proximal frame which is artifact data, The medical imaging method according to claim 1, further comprising the above.

11. At least one processor, A medical imaging apparatus comprising at least one computer-readable storage medium that communicates with the at least one processor, The at least one computer-readable storage medium stores instructions for the at least one processor and the at least one computer-readable storage medium. The instructions are, Acquire imaging data that includes at least fluorescence imaging data. To detect artifact data in the aforementioned fluorescence imaging data, By removing the artifact data or by changing the artifact data in the fluorescence imaging data to a specific value, corrected fluorescence imaging data is generated, and The process involves generating an image based on the modified fluorescence imaging data. Medical imaging device.

12. The aforementioned imaging data further includes optical coherence tomography (OCT) imaging data, The artifact data is detected based on the OCT imaging data. The medical imaging apparatus according to claim 11.

13. In order to detect the artifact data, the instruction causes the at least one processor and the at least one computer-readable storage medium to perform the following operations: To detect a first angular position that includes an OCT imaging value that changes beyond a first threshold, Detecting a second angular position that includes an OCT imaging value that changes beyond a second threshold, and The system is configured to define the detected range between the first angular position and the second angular position as the artifact data. The medical imaging apparatus according to claim 12.

14. The instructions cause the artifact data to be further detected based on information about structures shown in the fluorescence imaging data, which is stored in the at least one processor and the at least one computer-readable storage medium. The medical imaging apparatus according to claim 11.

15. The at least one computer-readable storage medium further stores instructions in the at least one processor and the at least one computer-readable storage medium to change the fluorescence imaging data within a predetermined range near the artifact data to the specific value. The medical imaging apparatus according to claim 11.

16. The aforementioned specific value is zero or null. The medical imaging apparatus according to claim 11.

17. The region of the aforementioned image corresponding to the artifact data is displayed in a predetermined color. The medical imaging apparatus according to claim 11.

18. The at least one computer-readable storage medium further stores instructions for the at least one processor and the at least one computer-readable storage medium to perform the analysis of the modified fluorescence imaging data. The medical imaging apparatus according to claim 11.

19. Probe interface subsystem and Patient interface unit, A curved optical imaging device, At least one processor, A medical imaging system comprising at least one computer-readable storage medium that communicates with the at least one processor, The at least one computer-readable storage medium stores instructions for the at least one processor and the at least one computer-readable storage medium. The instructions are, Acquire imaging data that includes at least fluorescence imaging data. To detect artifact data in the aforementioned fluorescence imaging data, By removing the artifact data or by changing the artifact data in the fluorescence imaging data to a specific value, corrected fluorescence imaging data is generated, and The process involves generating an image based on the modified fluorescence imaging data. Medical imaging system.

20. The probe interface subsystem, the patient interface unit, and the curved optical imaging device perform both optical coherence tomography and fluorescence imaging. The medical imaging system according to claim 19.

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