Fundus imaging for microvascular assessment

Abstract

An example system for performing a microvascular assessment on a patient includes a fundus imaging device, which includes: a camera configured to capture one or more images of the patient's eye; and at least one light source; and a microvascular assessment computing device, which includes: a processor; and a memory encoding instructions, which when the processor executes the instructions cause the system to: activate the light source to direct light to the patient's fundus; capture one or more images of the patient's fundus with the camera, the fundus including a plurality of blood vessels; and analyze the one or more images with the microvascular assessment computing device to determine a microvascular health index of the patient.

Description

Background Art

[0001] It is often observed that certain patients diagnosed with a disease have mild symptoms at onset but then rapidly deteriorate. For example, patients diagnosed with sepsis or coronavirus disease may have mild symptoms that later trigger acute respiratory distress, multi-organ failure, septic shock, and blood clots.

[0002] In patients diagnosed with sepsis or coronavirus disease, endothelial cell dysfunction may occur, leading to microvascular problems and rapid patient deterioration. Microvascular changes may precede changes in macroscopic vital signs, such as heart rate, respiratory rate, and blood pressure, and help predict patient deterioration. Summary of the invention

[0003] Embodiments of the present disclosure are directed to performing microvascular assessment on a patient using a fundus imaging device.

[0004] The details of one or more techniques are set forth in the accompanying drawings and the following description. Other features, objects, and advantages of these techniques will be apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 is a schematic diagram showing an example system for microvascular assessment of a patient;

[0006] Figure 2 To provide Figure 1 A block diagram of a detailed illustrated illustration of a fundus imaging device;

[0007] Figure 3 To provide Figure 1 A block diagram of a detailed illustrated illustration of a microvascular assessment computing device;

[0008] Figure 4 for Figure 1 Example embodiments of fundus imaging devices;

[0009] Figure 5 for Figure 4 Another view of the fundus imaging device;

[0010] Figure 6 for Figure 4 Another view of the fundus imaging device;

[0011] Figure 7 for Figure 4 Another view of the fundus imaging device;

[0012] Figure 8 A flowchart of an example method for evaluating a patient's microvasculature;

[0013] Fig. 9 Shows the use of Figure 8 A series of example images taken by the method;

[0014] Fig.10 A flowchart of another exemplary method for assessing a patient's microvasculature;

[0015] Fig.11 An example is shown for two different fundus images;

[0016] Fig.12 A flowchart of another exemplary method for assessing a patient's microvasculature;

[0017] Fig.13 To be used to implement Figure 1 Schematic block diagram of an example computing device that implements various aspects of a fall risk management system. DETAILED DESCRIPTION

[0018] Microvascular assessment of a subject is critical for diagnosis and monitoring of a number of critical and emergency situations including sepsis. The effects of endothelial dysfunction on microvascular structure, function, and most importantly appearance are well documented. There are significant difficulties in locating and imaging such tissue beds in vivo. While the sublingual area, nail folds, and other areas have been explored, a very rich source of dense vascular structures exists in the eye. The retina is a very dense layer composed of vascular content.

[0019] Fundus imaging is optimized to provide good images of the retina, optic nerve, optic disc, optic cup, and other areas. In addition, to obtain good dynamic contrast and accurate color reproduction, fundus imaging is typically performed using high-intensity flashes of neutral white light. This has the deleterious effect of causing pupil constriction, limiting the achievable field of view. This also limits the ability to continuously image blood vessels without dilation or patient discomfort.

[0020] The present disclosure is directed to methods and systems for evaluating microvascular health of a patient using a fundus imaging device. As used herein, "fundus" refers to the fundus, including the retina, optic nerve, macula, vitreous body, choroid, and posterior pole. In some embodiments, the fundus imaging device is improved to improve its ability to directly evaluate endothelial cell dysfunction in a patient.

[0021] Figure 1A schematic diagram of an example system 100 for patient microvascular assessment is shown. Similar systems are described in U.S. Patent Application No. 16 / 443,234 filed on June 17, 2019, U.S. Patent Application No. 16 / 229,939 filed on December 21, 2018, and U.S. Patent Application No. 16 / 230,315 filed on December 21, 2018, the entire contents of which are incorporated by reference in this disclosure. The system 100 includes a fundus imaging device 102, which includes a microvascular assessment computing device 104 that communicates with a network 106.

[0022] Clinician C operates the fundus imaging device 102 to capture an image of the eye of patient P. In some embodiments, the fundus imaging device 102 operates to capture one or more images of the fundus. In some embodiments, the fundus imaging device 102 operates to capture a series of images of the pupil of patient P. In some embodiments, the fundus imaging device 102 operates to capture one or more images of blood vessels (including microvessels) visible in the fundus of patient P. Figure 1 As shown, the fundus imaging device 102 includes a microvascular assessment computing device 104. However, the microvascular assessment computing device 104 may be installed on a remote server that communicates with the fundus imaging device 102 via a network 106.

[0023] The microvascular assessment computing device 104 operates to analyze the images captured by the fundus imaging device 102. The images are analyzed to assess the microvasculature of the patient P. The clinician C may utilize the assessment to determine the clinical condition of the patient P.

[0024] The exemplary fundus imaging device 102 is connected to a network 106. The network 106 may include any type of wireless network, wired network, or any communication network known in the art. For example, the wireless connection may include a cellular network connection and a connection using protocols such as 802.11a, 802.11b, and / or 802.11g. In other examples, a wireless connection may be directly made between the fundus imaging device 102 and an external display using one or more wired or wireless protocols, such as Bluetooth, Wi-Fi Direct, Radio Frequency Identification (RFID), or Zigbee. Other configurations are also possible.

[0025] The system 100 can be used to assist clinician C in screening, monitoring, or diagnosing various eye diseases, such as hypertensive eye disease, diabetic retinopathy, glaucoma, and papilledema. The system 100 can also be used to assist clinician C in screening for signs of endothelial deterioration, which is an early sign of various health conditions, such as sepsis. It should be understood that the clinician C operating the fundus imaging system 102 may be different from the clinician C evaluating the resulting images.

[0026] Figure 2To provide Figure 1 FIG. 1 is a block diagram of a detailed diagrammatic illustration of a fundus imaging device 102 of FIG. 1 . In this example, the fundus imaging device 102 includes a camera 120, a computing device 122, a display 124, a light source 128, a filter 130, and a microvascular assessment computing device. In some embodiments, the fundus imaging device 102 may include fewer or more components depending on the specific intended use of the fundus imaging device 102.

[0027] The camera 120 operates to record images of the patient's eyes. In some embodiments, the camera 120 is a digital camera including a lens, an aperture, and a sensor array. In some embodiments, the lens of the camera 120 is a variable focus lens, such as a lens moved by a stepper motor, or a liquid-containing lens, also known in the art as a liquid lens. In some embodiments, the camera 120 is configured to record images of the fundus of one eye at a time. In other embodiments, the camera 120 is configured to record images of both eyes substantially simultaneously. In those embodiments, the fundus imaging device 102 may include two independent cameras 120, one for each eye.

[0028] The computing device 122 operates to execute software programs and access data. The computing device 122 includes at least one processor and at least one memory. The computing device 122 regulates the operation of the camera 120, the display 124, and other components of the fundus imaging device 102. The computing device 122 also mediates communications via the network 106. Fig.13 A more detailed view of an example computing device 122 is provided.

[0029] The display 124 operates to provide visual output to the clinician C operating the fundus imaging device 102. In some embodiments, the housing supports the display 124. The display 124 operates to reproduce the image produced by the fundus imaging device 102 in a size and format that can be read by the clinician C. For example, the display 124 can be a liquid crystal display (LCD) and an active matrix organic light emitting diode (AMOLED) display. The display can be touch sensitive.

[0030] Light source 128 operates to direct light to the patient's eye. In some embodiments, light source 128 is an infrared LED. In some embodiments, light source 128 is a visible light LED. In some embodiments, light source 128 includes an infrared LED and a visible light LED. In some embodiments, light source 128 is used to provide continuous light. In some embodiments, light source 128 is used to provide a brief flash of light.

[0031] The filter 130 operates to selectively transmit light within a specific wavelength range. In some embodiments, the filter 130 is a bandpass filter configured to filter out light of all wavelengths within the specific wavelength range. In some embodiments, the bandpass filter is configured to allow only yellow light and green light to pass. In some embodiments, the filter 130 is a polarization filter configured to allow light waves of a specific polarization to pass while blocking light waves of other polarizations.

[0032] In some embodiments, a phase-adjustable linear polarizer is provided at the illumination source and the image return path of the fundus imaging device 102. Generally speaking, in imaging systems, polarization can be used to manage reflections and suppress glare from linear artifacts. This is used here to enhance the linear appearance of microvessels at several target vessel locations. Microvascular images are captured continuously. During image capture, the polarizer is gradually rotated over a range of about 90 degrees. An image difference algorithm is used to extract the image at the optimal polarization angle.

[0033] Figure 3 To provide Figure 1 and Figure 2 FIG. 1 is a block diagram of a detailed diagrammatic illustration of a microvascular assessment computing device 104. In this example, the microvascular assessment computing device 104 includes an image processor 150, a microvascular health index calculator 152, a pupil reactivity calculator 154, a microvascular density calculator 156, and a QRS waveform coordinator 158.

[0034] The image processor 150 operates to manipulate and modify the images received from the fundus imaging device 102. Such manipulations are used to enhance various aspects of the images to facilitate detection of various parameters of blood vessels.

[0035] The microvascular health index calculator 152 operates to determine a microvascular health index of the patient based on an analysis of one or more images captured by the fundus imaging device 102. In some embodiments, the images are manipulated and modified by the image processor 150 prior to analysis. In some embodiments, other components of the microvascular assessment computing device 104, such as the pupil reactivity calculator 154 or the microvascular density calculator 156, operate in conjunction with the microvascular health index calculator 152 to determine the clinical condition of the patient. The overall endothelial health of the patient can be inferred based on various measurements of the patient's eye. In some embodiments, the microvascular health index is based on comparisons with other patients having similar demographic characteristics as the patient being examined.

[0036] The pupil reactivity calculator 154 operates to measure the diameter of the patient's pupil over time in response to light stimulation. Responsiveness is based on: 1) how quickly the pupil closes or opens, 2) how far the pupil closes or opens, and 3) how long the pupil remains closed or open.

[0037] The microvessel density calculator 156 operates to measure Fig.10 The ratio of the diameter and distance of the branch position described in .

[0038] The QRS waveform coordinator 158 operates to receive ECG data from the ECG machine. The QRS waveform of several heartbeats is used to time the analysis of the captured fundus images, as further described below.

[0039] Figure 4-7 An example of a fundus imaging device 102 is shown that includes a housing 170 that supports the components of the device. The housing 170 supports the display 124 at a first end 172 and is configured to engage one or both eyes of a patient P at an opposite end 174. As described herein, the fundus imaging device 102 can be used to implement one or more of the fundus and microvascular imaging methods described herein.

[0040] like Figure 5 and Figure 7 As shown, the housing 170 includes an opening 178 for imaging one or both eyes at a time. The camera 120 of the fundus imaging device 102 is located in a cavity 180 formed at one end 174 of the housing 170. In some examples, the housing 170 supports a structure for raising and lowering the camera 120 to align it with the eyes of the patient P. When the housing 170 is against the head of the patient P, the camera 120 can be moved in three directions to complete the imaging of both eyes of the patient P.

[0041] The housing 170 supports a position guide for the patient P, such as a surface 182 on the other end 174 of the housing 170, which is configured to engage the head of the patient P. In some embodiments, the housing 170 may also support additional position guides, such as an optional adjustable chin rest. The surface 182 is configured to fit snugly over the head of the patient P and surround both eyes of the patient P. When the patient P uses the fundus imaging device 102 to capture one or more images of their eyes, for example without the help or assistance of the clinician C, a position guide such as the surface 182 can help the patient P align their eyes with one or both holes 178.

[0042] exist Figure 4-7 In the example embodiment shown, housing 170 supports display 124. In some embodiments, system 100 may also use an auxiliary display as part of a smartphone, tablet, or external display located separately from housing 170 to display at least one image captured by camera 120.

[0043] The display 124 operates to reproduce the images captured by the fundus imaging device 102 in a size and format that can be read by the clinician C. For example, the display 124 can be a liquid crystal display (LCD) and an active matrix organic light emitting diode (AMOLED) display. The display can be touch sensitive.

[0044] The housing 170 of the exemplary fundus imaging device 102 is handheld in size. The display 124 can display images of the eye and controls for capturing those images. In some embodiments, the display 124 is a touch screen. In some embodiments, the housing 170 also supports one or more user input buttons near the display 124. The display 124 and the user input buttons can be used to capture one or more images of the patient P's eye. Therefore, the fundus imaging device 102 can be configured so that the clinician C can complete one or more automatic and / or manual workflows to capture images of the patient P's eye.

[0045] In addition, the fundus imaging device 102 can be configured to automatically execute a workflow to capture one or more images of the eye of the patient P without requiring the patient or clinician C to use the display 124 or one or more user input buttons near the display 124 to control the operation of the fundus imaging device 102. This configuration is helpful when the patient P uses the fundus imaging device 102 without the assistance of the clinician C, such as when the fundus imaging device 102 is used to monitor the progression of an infectious disease such as a coronavirus (e.g., COVID-19), to reduce exposure to clinicians C and other caregivers in an acute care space such as a hospital intensive care unit.

[0046] The fundus imaging device 102 can detect when the eye of the patient P is aligned with one or two holes 178 located at one end 174 of the housing 170, so that the patient P is positioned and ready for the image capture sequence. In some embodiments, the camera 120 of the fundus imaging device 102 can detect when the eye of the patient P is aligned with one or two holes 178.

[0047] Figure 8 Flow chart of an exemplary method 200 for evaluating microvessels in a patient's eye. In particular, the method 200 utilizes fluorescent dyes to image blood flow in microvessels in the patient's eye. In some embodiments, the method 200 comprises Figure 1-3 The system 100 described in the embodiment of the present invention is implemented.

[0048] In operation 202, a fluorescent dye is injected into the patient's bloodstream. In some embodiments, the fluorescent dye is fluorescein. Fluorescein is a fluorophore with an excitation peak at 494 nm and an emission peak at 521 nm. When fluorescein is exposed to infrared light, it emits a bright yellow-green light.

[0049] In operation 204, a fundus imaging device is positioned at the patient's eye. In some embodiments, the fundus imaging device is positioned at the patient's eye. Figure 1 In some embodiments, color bandpass filtering is performed on the fundus imaging device 102. The bandpass filter is selected to allow yellow-green light to pass through, but filter out all other light.

[0050] In operation 206, the infrared LED light source of the fundus imaging device is activated so that the infrared light is directly irradiated to the fundus of the patient. In some embodiments, the infrared light excites the fluorescent dye to emit yellow-green light.

[0051] In operation 208, a series of images of the patient's fundus are captured. These images include microvessels, which are illuminated as fluorescent dye is pumped into the fundus through the patient's blood vessels. As the patient's heart continues to beat, the fluorescent dye is pumped out of the fundus and the yellow illumination disappears. In some embodiments, the series of images is recorded by the camera 120 of the fundus imaging device 102.

[0052] In operation 210, the series of images is analyzed to determine the penetration and dispersion rates of the fluorescent dye in the blood vessels of the fundus. In some embodiments, the images are analyzed by the image processor 150 of the microvascular assessment computing device 104. In some embodiments, the penetration and dispersion rates are determined by an image processing algorithm based on how the number of yellow pixels and green pixels changes over time. These rates are affected by the microvascular health of the patient. If the amount of fluorescent dye detected in the blood vessels does not reach a minimum threshold, or if the fluorescent dye takes a long time to enter the blood vessels of the fundus, this may indicate that an underlying health problem is affecting the endothelial health of the patient.

[0053] In operation 212, the microvascular health index of the patient is calculated. In some embodiments, the microvascular health index calculator 152 performs this step based on the penetration rate and dispersion rate determined in operation 210. The microvascular health index can prompt the clinician C when the patient P may need additional medical attention or diagnostic testing.

[0054] Fig. 9 Clarifies the use Figure 8 A series of example images 230 captured by the method. Panel (a) shows the fluorescent dye beginning to penetrate small blood vessels in the fundus. In panel (b), the fluorescent dye has penetrated most of the blood vessels. In panel (c), the peak level of the fluorescent dye in the fundus is recorded. In panel (d), the fluorescent dye has begun to disperse from the blood vessels. In general, the level of fluorescence detected in the fundus should increase first and then decrease, so that if the level is plotted as a graph, the graph will create a curve.

[0055] Fig.10Flow chart of another example method 250 for evaluating microvasculature of a patient. In particular, the method 250 analyzes fundus images to quantify vessel density in microvasculature of the patient's eye. In some embodiments, the method 200 comprises Figure 1-3 The system 100 described in the embodiment of the present invention is implemented.

[0056] In operation 252, a fundus imaging device is positioned at the patient's eye. In some embodiments, the fundus imaging device is positioned at the patient's eye. Figure 1 The fundus imaging device 102. In some embodiments, a wide field of view is selected to capture images.

[0057] In operation 254, a fundus image is captured. In some embodiments, the patient's eye is illuminated with infrared or near-infrared light to eliminate the effects of light exposure on the pupil so that a wide field of view can be captured. In some embodiments, images are captured using lower levels of visible light illumination to allow for a wider field of view.

[0058] In some embodiments, at low levels of illumination, longer exposure times may be required to properly image the fundus. In such embodiments, due to the dynamic nature of the task (eye movement), multiple captured frames are stitched together algorithmically. The retina is represented algorithmically. Images are repositioned and aligned to a common centroid point. Multiple images are grouped into statistical stacks to increase dynamic range and fidelity and reduce background noise.

[0059] In some embodiments, fundus near-dark imaging is utilized. Sensitivity enhancement DQE utilizes actively cooled CMOS, SIPM / SPAD imagers. Boundaries are set at the desired flux level. The imager is used in conjunction with the patient LUT to determine the thermal load required for the imager to achieve the sensitivity and DQE for proper imaging.

[0060] In operation 256, the fundus image is operated to locate the edges of the patient's fundus blood vessels. In some embodiments, an algorithm is used to modify the image to enable identification of blood vessel branches. Image contrast is expanded. Color thresholding techniques are used to highlight major blood vessels. Continuous morphological erosion and dilation are used to locate the edges of blood vessels.

[0061] In operation 258, the vessels are traced from the primary arterial structure to determine the location of branch points of the vessels. Root nodes for identifying primary arterial and venous structures are found using atlas-based analysis. The genetic snake algorithm is rooted in tracing the primary arterial locations and primary venous locations of the vascular tree structure. Along each path of the structure, branch points are enumerated where the left or right edge of the tree generated by the snake algorithm is lost.

[0062] The diameter of the vessel before and after each branch point location is calculated in operation 260. The diameter is measured to account for vessel width using known photogrammetry techniques using branch point locations and imaging equipment.

[0063] In operation 262, the distances between the branch point locations are measured. The distances between consecutive branch point locations are measured.

[0064] In operation 264, the ratio of the diameter of the branch point location to the distance between the branch point locations is calculated. For each calculation, the diameter of the branch location to the distance to the next (or previous) branch along the tree is calculated. In some embodiments, the central retinal vein equivalent diameter (CRVE) and the central retinal artery equivalent diameter (CRAE) are segmented from the visible image using a local atlas based segmentation calculation. Finally, a final trace measure of the vessel diameter ratio and the number of branches on a single path is calculated.

[0065] At operation 266, clinical characteristics of the patient are determined based on the calculated ratios. These ratios are used to determine an absolute measure of vascular shunting and are correlated with the clinical characteristics.

[0066] In some embodiments, after operation 264, the field of view is adjusted to locate the secondary descendants of the primary blood vessels at the extremes of the eye.Another iteration of operations 256, 258, 260, 262, and 264 may be performed.

[0067] Fig.11 An example is shown for two different fundus images. The left fundus image 290 shows more branches than the right fundus image 292. Therefore, the ratios of the two images will be very different.

[0068] Fig.12 Flow chart of another example method 300 for evaluating a patient's microvasculature. In particular, method 300 measures the patient's pupil's response to light stimulation. The rate at which the pupil constricts can be a meaningful metric for measuring the patient's overall health. In some embodiments, method 300 comprises Figure 1-3 The system 100 may be executed by one or more components of the system 100.

[0069] In operation 302, a fundus imaging device is positioned at the patient's eye. The fundus imaging device includes at least one camera and a visible light source. In some embodiments, the fundus imaging device is Figure 1 A fundus imaging device 102 is provided.

[0070] In operation 304, images of the eye are continuously captured. In some embodiments, the camera captures images at a frequency of approximately 100 frames per second.

[0071] In operation 306, the baseline diameter of the pupil in the image is measured. This measurement is performed under stable conditions with low ambient lighting. In some embodiments, this step is performed by Figure 3 The image processor 150 executes.

[0072] In operation 308, a visible light source is activated to direct light into the patient's eye. The light causes the patient's pupil to contract. In operation 310, the diameter of the pupil is measured as the pupil dilates and contracts over time.

[0073] In one embodiment, a visible light source is activated to provide a brief flash of light. The diameter of the pupil is continuously measured as the pupil contracts in response to the light. Measurements are continued after the light stops until the pupil begins to dilate again. This is known as edge threshold detection.

[0074] In another embodiment, a visible light source is activated to slowly increase in brightness. A priori targets are selected for the starting and ending diameters of the pupil. The amount of illumination flux required to produce a pupil constriction response is measured. A metric is used to determine the sensitivity of the pupil.

[0075] Returning to operation 312, the pupil reactivity index is calculated. The pupil reactivity index is calculated using the peak values ​​of acceleration, velocity, and pupil diameter. In some embodiments, this step is performed by Figure 3 The pupil reactivity calculator 154 is implemented. The clinician can use the reactivity index to determine the patient's general health level.

[0076] Other methods of evaluating microvascular health and endothelial health can also be implemented using the fundus imaging device 102. In one example, a method of evaluating a patient's microvasculature includes fundus image capture synchronized with QRS waveform data. The blood vessels mechanically deform to reflect changes in blood pressure and blood flow rate. The interval time to reach peak flow changes will cause the expansion and contraction of the blood vessels. This elasticity can be measured as a function of flow rate.

[0077] A fundus imaging device is positioned at the patient's eye. A camera of the fundus imaging device operates to continuously capture images of the patient's eye. While fundus imaging is occurring, several heart cycles of the patient are recorded. In some embodiments, the heartbeat is recorded using an echocardiograph (ECG). QRS waveform data is used to synchronize the fundus image with the heartbeat cycle. Post-capture analysis is performed. Image segmentation and vessel identification are performed. Correlated differential imaging is used to subtract the peak vessel diameter from the minimum vessel diameter at a number of locations along the imaged microvascular fenestrations based on the heartbeat pattern. Coaxial vessel motion can also be measured at the registration points using a similar method. These measurements are then used to calculate the patient's compliance factor, which represents the clinical condition of the endothelium.

[0078] In another example, cellular measurements are taken of endothelial cells on the inner layer of the cornea to directly assess the endothelial health of a patient. Different imaging planes and tasks are combined with a fundus imaging device. This is used to image individual cells of the endothelial layer of the cornea. These images are then used to calculate the ratio of damaged cells to healthy cells. The fundus imaging device is located at the patient's eye. The fundus imaging device is modified to include a camera with polarization filtering, dark field illumination, and high magnification. Images of individual endothelial cells on the inner layer of the cornea of ​​the eye are captured. The ratio of damaged endothelial cells to healthy endothelial cells is calculated. This ratio can provide useful information to the clinician in determining the endothelial health of the patient.

[0079] Fig.13 4 is a block diagram showing an example of physical components of computing device 400. Computing device 400 may be any computing device used in conjunction with system 100 for performing microvascular assessment on a patient, such as Figure 2 computing device 122.

[0080] exist Fig.13 In the example shown, computing device 400 includes at least one central processing unit ("CPU") 402, system memory 408, and system bus 422, which connects system memory 408 to CPU 402. System memory 408 includes random access memory ("RAM") 410 and read-only memory ("ROM") 412. A basic input / output system containing basic routines that help transfer information between elements within computing device 400, such as during startup, is stored in ROM 412. Computing device 400 also includes mass storage device 414. Mass storage device 414 is capable of storing software instructions and data.

[0081] The mass storage device 414 is connected to the CPU 402 via a mass storage controller (not shown) connected to the system bus 422. The mass storage device 414 and its associated computer-readable storage media provide non-volatile, non-temporary data storage for the computing device 400. Although the description of computer-readable storage media contained herein refers to large-scale storage devices, such as hard disks or solid-state drives, it should be understood by those skilled in the art that computer-readable data storage media can include any available tangible physical device or product from which the CPU 402 can read data and / or instructions. In some embodiments, the computer-readable storage media includes completely non-temporary media.

[0082] Computer-readable storage media include volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storing information, such as computer-readable software instructions, data structures, program modules or other data. Example types of computer-readable data storage media include, but are not limited to, RAM, ROM, EPROM, EEPROM, flash memory or other solid-state storage technology, CD-ROMs, digital versatile disks ("DVD"), other optical storage media, magnetic cassettes, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by the computing device 400.

[0083] According to various embodiments, computing device 400 can operate in a networked environment using a logical connection to a remote network device through a network 421 (such as a wireless network, the Internet, or other types of networks). Computing device 400 can be connected to network 421 via a network interface unit 404 connected to system bus 422. It should be understood that network interface unit 404 can also be used to connect to other types of networks and remote computing systems. Computing device 400 also includes an input / output controller 406 for receiving and processing input from many other devices, including a touch user interface display screen or other types of input devices. Similarly, input / output controller 406 can provide output to a touch user interface display screen or other types of output devices.

[0084] As briefly described above, the mass storage device 414 and RAM 410 of the computing device 400 can store software instructions and data. The software instructions include an operating system 418 suitable for controlling the operation of the computing device 400. The mass storage device 414 and / or RAM 410 also store software instructions that, when executed by the CPU 402, enable the computing device 400 to provide the functionality discussed herein. For example, the mass storage device 414 and / or RAM 410 can store software instructions that, when executed by the CPU 402, enable the computing device 400 to control the operation of the camera 120.

[0085] Although various embodiments are described herein, those skilled in the art will appreciate that many modifications may be made thereto within the scope of the present disclosure. Therefore, the examples provided are not intended to limit the scope of the present disclosure in any way.

Claims

1. A system for performing microvascular assessment on a patient, the system comprising: Fundus imaging device, comprising: a camera configured to capture one or more images of the patient's eye; and at least one light source; and Microvascular assessment computing device, comprising: Processor; and a memory encoding instructions that, when executed by the processor, cause the system to: activating the light source so that light is directed toward the fundus of the patient's eye; capturing one or more images of a fundus of a patient's eye with the camera, the fundus comprising a plurality of blood vessels; and The one or more images are analyzed using a microvascular assessment computing device to determine the penetration rate and dispersion rate of the fluorescent dye in the fundus blood vessels, and based on the penetration rate and the dispersion rate, a microvascular health index of the patient is determined.

2. The system according to claim 1, wherein: The at least one light source is an infrared light emitting diode.

3. The system according to claim 1, wherein: The memory also encodes instructions that, when executed by the processor, cause the system to measure a diameter of a patient's pupil.

4. The system according to claim 1, wherein: The memory also encodes instructions that, when executed by the processor, cause the system to: operating the one or more images of the fundus to locate the edge of a fundus blood vessel; Tracing the blood vessel from the primary artery to determine the location of the branch point of the blood vessel; Calculating the diameter of the blood vessel before and after each branch point; Determine the distance between each branch point location; and The ratio of the diameter of the branch point positions and the distance between the branch point positions is calculated.

5. The system of claim 1, further comprising a color bandpass filter.

6. The system of claim 1, further comprising a polarization filter.

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