Magnetic resonance imaging technique integrating variable rate selective excitation (VERSE) and flow compensation along slices

Abstract

Magnetic resonance imaging techniques are described that integrate variable rate selective excitation (VERSE) and flow compensation along slices. According to an example, a method includes determining, by a device including a processor, a two-dimensional (2D) spin echo sequence adapted to acquire signal data associated with a slice of an anatomical region of a subject via an MRI system, determining the 2D spin echo sequence includes determining the 2D spin echo sequence according to a combination of a VERSE protocol and a flow compensation protocol along slices. The method further comprises: controlling, by the device, the MRI system to acquire signal data using a 2D spin echo sequence; and reconstructing, by the device, an image of the slice from the signal data.

Description

Technical Field

[0001] The present application relates to magnetic resonance imaging (MRI), and more particularly to an MRI technique integrating variable rate selective excitation (VERSE) and flow compensation along a slice. Background Art

[0002] The specific absorption rate (SAR) is a measure of the rate at which the body absorbs energy when exposed to a radio frequency (RF) electromagnetic field during a magnetic resonance imaging (MRI) scan. SAR is typically measured in watts per kilogram (W / kg). During an MRI scan, the RF pulses used to excite protons in the body can cause heating of the tissue. SAR quantifies the amount of energy absorbed by the body over time per unit mass. An important safety consideration in MRI is ensuring that the amount of energy absorbed does not exceed safe limits to prevent tissue heating and potential side effects. Although MRI is generally considered a safe imaging modality, excessive tissue heating can lead to burns, nerve irritation, and other adverse effects.

[0003] Flow compensation is a technique used in magnetic resonance imaging (MRI) to minimize or eliminate the effects of motion-related artifacts (referred to herein as flow artifacts) in acquired images caused by flowing materials in the body, such as blood or cerebrospinal fluid. When imaging moving tissue or fluids, such as blood vessels or cerebrospinal fluid, motion can cause unwanted artifacts in MRI images. These flow artifacts can distort the imaged anatomical structures and potentially lead to misinterpretation of the results.

[0004] Along-slice flow compensation in MRI refers to the application of flow compensation techniques to minimize or eliminate flow artifacts caused by motion perpendicular to the imaging plane, commonly encountered in multi-slice imaging sequences in two-dimensional (2D) MRI. In 2D MRI, slice selection is achieved by applying a gradient magnetic field along the direction of the slice (typically the z-direction in conventional MRI scanners). During the acquisition of multiple slices, there may be movement or flow of material perpendicular to the slice direction, which may lead to phase errors and flow artifacts in the acquired images. In order to compensate for this motion and minimize its effects, along-slice flow compensation techniques can be employed. These techniques typically involve modifying the slice selection gradient waveform to account for motion in the slice direction. By carefully timing the application of the gradient pulses in the slice selection direction, it is possible to eliminate or minimize the effects of motion-induced phase shifts along the slice direction.

[0005] In 2D MRI scans involving multiple slices to cover the anatomical region of interest, using along-slice flow compensation is crucial for reducing flow artifacts. Unfortunately, existing spin-echo sequences for multi-slice imaging can be very SAR-intensive. Therefore, techniques for reducing SAR in multi-slice 2D MRI scans that integrate along-slice flow compensation are desirable. Summary of the Invention

[0006] The following presents a summary of the invention to provide a basic understanding of one or more embodiments of the present invention. This summary is not intended to identify key or important elements, nor is it intended to delineate any scope of the different embodiments or any scope of the claims. Its sole purpose is to present the concepts in a simplified form as a prelude to the more detailed description that will be presented later. In one or more embodiments, a system, computer-implemented method, apparatus, and / or computer program product are described that provides MRI technology that integrates variable rate selective excitation (VERSE) and flow compensation along a slice.

[0007] According to an embodiment, an MRI system is provided, the MRI system comprising at least one memory storing computer-executable components and at least one processor executing the computer-executable components stored in the at least one memory. The computer-executable components include a configuration component that determines a 2D spin echo sequence suitable for acquiring signal data associated with a slice of an anatomical region of a subject via the MRI system, wherein the configuration component determines the 2D spin echoes based on a combination of a VERSE protocol and a flow compensation protocol along the slice. The computer-executable components further include a control component that controls the acquisition of the signal data by the MRI system using the 2D spin echo sequence, and a reconstruction component that generates an image of the slice from the signal data.

[0008] To this end, based on determining a 2D spin echo sequence according to the combination, the image comprises a defined image quality and the acquired SAR is reduced relative to another similar acquisition using a similar 2D spin echo sequence defined according to the along-slice flow compensation protocol and without the VERSE protocol. In this regard, the defined image quality includes the absence of flow artifacts or an amount of flow artifacts less than a defined amount.

[0009] In some embodiments, the elements described in the systems disclosed herein may be embodied in various forms, such as a computer-implemented method, a computer program product, or another form. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 An exemplary MRI system according to one or more embodiments of the disclosed subject matter is presented.

[0011] Figure 2 A block diagram of an exemplary operating apparatus of an MRI system that facilitates integration of variable rate selective excitation (VERSE) and flow compensation along a slice is presented, in accordance with one or more embodiments of the disclosed subject matter.

[0012] Figure 3A and Figure 3B Exemplary fast spin echo (FSE) sequence waveforms according to flow compensation along a slice with and without VERSE according to one or more embodiments of the disclosed subject matter are presented.

[0013] Figure 4A and Figure 4B Close-up views of slice selection gradients according to exemplary FSE sequence waveforms with and without along-slice flow compensation with VERSE, according to one or more embodiments of the disclosed subject matter, are presented.

[0014] Figure 5 A magnified view of the shape of a slice selection gradient of an exemplary FSE sequence waveform incorporating along-slice flow compensation without VERSE, according to one or more embodiments of the disclosed subject matter, is presented.

[0015] Figure 6 A magnified view of the shape of a slice selection gradient of an exemplary FSE sequence waveform incorporating along-slice flow compensation with VERSE, according to one or more embodiments of the disclosed subject matter, is presented.

[0016] Figure 7 Exemplary nonlinear VERSE slice selection gradients according to one or more embodiments of the disclosed subject matter are presented.

[0017] Figure 8 Exemplary MRI images acquired using different acquisition protocols in accordance with one or more embodiments of the disclosed subject matter are presented.

[0018] Figure 9 A high-level flow chart is presented of an exemplary computer-implemented method for performing an MRI scan using a VERSE protocol and an along-slice flow compensation protocol in accordance with one or more embodiments of the disclosed subject matter.

[0019] Figure 10 A high-level flow chart is presented of another exemplary computer-implemented method for performing an MRI scan using a VERSE protocol and an along-slice flow compensation protocol in accordance with one or more embodiments of the disclosed subject matter.

[0020] Figure 11 A block diagram illustrating an example non-limiting operating environment in which one or more embodiments described herein may be facilitated is shown. DETAILED DESCRIPTION

[0021] The following detailed description is merely illustrative and is not intended to limit the application or use of the embodiments and / or the embodiments. In addition, it is not intended to be bound by any express or implied information set forth in the aforementioned "Background Technology" section, "Summary of the Invention" section, or "Detailed Description of the Invention" section.

[0022] The disclosed subject matter relates to systems, computer-implemented methods, apparatus, and / or computer program products that provide MRI techniques that integrate variable rate selective excitation (VERSE) and flow compensation along a slice. As described in the background section, the use of flow compensation along a slice-selective direction is crucial for reducing flow artifacts in 2D MRI scans involving multiple slices to cover an anatomical region of interest. Unfortunately, existing spin echo sequences for multi-slice imaging, such as raw spin echo sequences, fast spin echo sequences (FSE), and turbo spin echo sequences, can be very SAR intensive. Therefore, techniques for reducing SAR in multi-slice 2D MRI scans that integrate flow compensation along a slice are desired.

[0023] Variable rate selective excitation (VERSE) is a technique used in MRI to selectively excite specific regions of interest with varying degrees of spatial resolution or signal intensity. In conventional MRI, the excitation pulses are typically applied uniformly across the entire imaging volume, resulting in uniform signal excitation and image contrast throughout the region of interest. However, in some cases, it may be desirable to selectively excite only specific regions within the imaging volume while suppressing signals from other regions. VERSE allows for the selective excitation of different regions within the imaging volume by adjusting the timing and characteristics of the excitation RF pulses. By modulating parameters such as pulse amplitude, duration, frequency, or phase, it is possible to customize the excitation profile for a specific region while minimizing signals from surrounding tissue. VERSE sequences are typically designed with careful consideration of pulse sequence parameters such as flip angle, repetition time, and pulse amplitude to achieve the desired imaging goals while minimizing RF power deposition. By optimizing these parameters, VERSE sequences can reduce the total RF power required for imaging and, in turn, reduce the SAR of the scan.

[0024] With this background in mind, the inventors of the subject innovation have implemented a mechanism that combines VERSE technology with along-slice flow compensation to reduce SAR in 2D MRI scans while improving image quality in flow-sensitive regions. In various embodiments, VERSE is used to define a 2D spin echo sequence with reduced RF power by reducing the peak amplitude of the RF pulse by a certain scaling factor and reshaping the corresponding slice-selective gradient waveform based on the scaling factor to excite the same slice. More specifically, the applied VERSE technology scales the slice-selective gradient waveform based on the (reduced) amplitude or RF pulse. These gradient waveforms are not constant, and the shapes of these gradient waveforms are irregular. In this regard, the slice-selective gradient waveforms customized by VERSE are not rectangular because they are shaped according to conventional along-slice flow compensation.

[0025] To this end, as described in the Background section, flow compensation along the slice also involves modifying the slice selection gradient waveform to account for motion in the slice direction. By carefully defining the parameters that control the shape and application timing of the slice selection gradient, it is possible to eliminate or minimize the effects of motion-induced phase shifts along the slice direction. However, the irregularities in the shape of the VERSE slice selection gradients generated as a result of applying the aforementioned VERSE technique present an obstacle to further tailoring the slice selection gradient waveform parameters in a manner that achieves the desired flow compensation effect.

[0026] To overcome this obstacle, the MRI sequence configuration software employed by the MRI system converts the irregularly shaped VERSE slice selection gradient waveform into a modeled equivalent rectangular shape, associated with the calculation of reference waveform parameters applicable to the slice selection gradient to achieve the desired flow compensation effect. In this regard, using rectangular shaped gradients, the configuration software calculates the area under each rectangular shaped gradient and uses these area metrics to calculate reference waveform parameter values. The configuration software then uses these reference waveform parameter values ​​to define an additional slice selection gradient waveform that facilitates flow compensation along the slice. This additional slice selection gradient waveform corresponds to a slice rephasing gradient waveform. The MRI system's configuration software then configures the MRI sequence using the irregularly shaped slice selection gradient (providing reduced SAR) and using the slice rephasing gradient waveform.

[0027] To this end, VERSE and along-slice flow compensation both involve tailoring the slice-select gradient waveform in different ways to achieve different goals. Due to the complexity of both techniques and the way the slice-select gradient waveform is adjusted relative to the two techniques, mechanisms for combining VERSE with along-slice flow compensation have not been explored in the art until now.

[0028] Depending on along-slice flow compensation, inaccuracies in gradient timing or calibration may result in incomplete flow compensation or unintended phase shifts, leading to artifacts in the acquired images. Therefore, proper calibration and adjustment of gradient timing are essential to minimize these errors. The inventors of the subject innovation have applied the disclosed mechanism of combining VERSE with along-slice flow compensation with a 2DFSE sequence to successfully generate MRI images of the spine with no flow artifacts and reduced RF power, thereby demonstrating how the disclosed techniques can be used in conjunction with VERSE to accurately calibrate and define slice-selective gradients for flow compensation.

[0029] One or more embodiments will now be described with reference to the accompanying drawings, wherein like reference numerals are used throughout to represent like elements. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a more thorough understanding of one or more embodiments. However, it will be apparent that in various circumstances, one or more embodiments may be practiced without these specific details.

[0030] Turning now to the accompanying drawings, Figure 1 An exemplary MRI system 100 is shown in accordance with one or more embodiments of the disclosed subject matter. The MRI system 100 includes an MRI machine 101 and an operating device 102 that controls the operation of the MRI machine 101. The operating device 102 can be communicatively and operably connected to the MRI machine 101 (and / or its corresponding elements) via a system bus 132 and / or via any suitable wired or wireless communication network. The operating device 102 can include or correspond to one or more computing devices that control the operation of the MRI machine 101, including controlling the acquisition (e.g., via a data acquisition unit 126) of magnetic resonance (MR) signal data associated with one or more slices of an anatomical region of a subject 118 for reconstructing images of the slices. The operating device 102 also receives the acquired MR signal data and performs image reconstruction using the MR signal data to generate an image. The operating device 102 can further display (e.g., via a suitable electronic display associated with the operating device 102) the reconstructed image, store the image, and / or send the image to another system / device. Reference is made below to Figure 2 Additional details regarding the features and functionality of operating device 102 are described.

[0031] MRI machine 101 may include or correspond to any existing or future MRI machine capable of performing any existing or future 2D MRI procedure (e.g., a spin echo procedure, a FSE procedure, a TSE procedure, etc.). As used herein, 2D MRI refers to an MRI procedure in which MR data is acquired in a series of 2D slices, each 2D slice representing a cross-sectional view of the anatomical structure being imaged. According to 2D MRI, MRI machine 101 acquires signal data one slice at a time, wherein each slice is sequentially acquired using a pulse sequence customized for the desired imaging plane (e.g., axial, sagittal, or coronal). Each 2D slice is independently reconstructed to generate a single 2D image. On the other hand, in 3D MRI, imaging data is acquired volumetrically, covering the entire imaging volume in three dimensions. MRI scanners typically use 3D imaging sequences such as 3D gradient echo or 3D TSE to acquire data in a single continuous 3D volume. The acquired 3D volume contains information about the entire imaged anatomical structure in three dimensions, without requiring continuous slice acquisition. Reconstruction of 3D MRI data involves processing the entire volumetric data set to generate a series of consecutive slices or multi-planar reformatting (MPR) at any desired orientation. To this end, the MRI system 100 may correspond to an MRI system capable of performing both 2D and 3D MRI scans, and the disclosed techniques are particularly related to optimizing 2D MRI sequences associated with performing 2D MRI scans.

[0032] Typically, the MRI machine 101 operates based on the principles of nuclear magnetic resonance (NMR) and utilizes a combination of strong magnetic fields, radio frequency (RF) pulses, and computer processing (performed via the data acquisition unit 126 and the operating device 102) to produce detailed images of the body's interior. In this regard, the human body is primarily composed of water molecules containing hydrogen atoms. When a subject 118 enters the MRI machine 101, the hydrogen nuclei (protons) in their body align with the strong, constant, and uniform magnetic field generated by the MRI machine 101. This main magnetic field is typically referred to as B0. The MRI machine 101 generates brief RF pulses directed toward the body region of the subject 118 being imaged. The RF pulses are tuned to the resonant frequency of the protons in the body, determined by the strength of the main magnetic field B0. When each RF pulse is applied, it disturbs the alignment of the protons, causing them to absorb energy and move out of alignment with the main magnetic field B0. This process is called excitation. After the RF pulse is turned off, the hydrogen nuclei gradually return to their initial alignment with the main magnetic field B0. As they do so, they emit RF signals, a process known as relaxation.

[0033] The RF coils within the MRI machine 101 detect RF signals emitted by relaxing protons. These RF signals contain information about the spatial distribution of protons within the body. The detected RF signals are converted into electrical signals (e.g., via the data acquisition unit 126) and sent to a computer (e.g., the operating device 102) for processing. The computer collects and organizes the signals based on their spatial information and signal intensity, storing them as raw data. Using complex algorithms, the computer processes the raw data to reconstruct detailed images of the body's interior. Different tissues in the body produce different signals based on their composition and structure, resulting in contrast in the final image.

[0034] To create an image, the MRI machine 101 employs gradient magnetic fields (generally referred to herein as gradients) that vary in intensity across the imaging volume. These gradients encode spatial information into the transmitted RF signals, allowing the MRI system 100 to determine the location of each received RF signal within the body. These gradient magnetic fields are additional magnetic fields superimposed on the main magnetic field B0. These gradients vary in intensity along the x, y, and z axes of the MRI scanner. Gradient coils within the MRI machine 101 generate these gradient magnetic fields. By controlling the intensity and timing of these gradients, combined with controlling the timing, intensity, and frequency of the RF pulses, spatial encoding is achieved, allowing the RF signals emitted from different regions of the body to be localized. The information that defines the specific intensities and timing of the RF pulses and gradients for a particular imaging slice is called an MRI sequence and is typically represented graphically as a waveform (e.g., such as waveforms 300A and 300B, referenced below). Figure 3A and Figure 3B In this regard, according to 2D MRI, an MRI sequence waveform defines the timing, shape, and characteristics of RF pulses, gradient magnetic fields, and a signal acquisition scheme that is applied to acquire MR signal data used to reconstruct images of slices of an anatomical region of a subject.

[0035] In this regard, the MRI machine 101 includes a static magnetic field magnet unit 104, a gradient coil unit 106, an RF body coil unit 108, one or more local RF coil arrays (112, 114, and 116), an RF port interface 122, a transmit / receive (T / R) switch 124, a data acquisition unit 126, an RF driver unit 128, and a gradient coil driver unit 130. The MRI machine 101 also includes a table on which an imaged subject 118 is positioned. By moving the table 110 based on control signals provided by the operating device 102, the subject 118 can be moved within and outside the imaging space 120.

[0036] The static magnetic field magnet unit 104 typically includes, for example, a toroidal superconducting magnet mounted within a toroidal vacuum vessel. The magnet defines a cylindrical space surrounding the subject 118 and generates a constant main static magnetic field B0. The MRI machine 101 also includes a gradient coil unit 106 that generates magnetic field gradients and a radio frequency (RF) system that includes an RF body coil unit 108 and / or one or more local RF coil arrays 112, 114, and 116 that transmit RF pulses directed toward tissue within a specific slice of the subject being imaged and receive RF signals emitted by protons during relaxation.

[0037] Based on the control signal from the operating device 102, a gradient waveform for performing a prescribed 2D scan is applied to the gradient coil unit 106 by the gradient coil driver unit 130 to generate a magnetic field gradient G for spatially encoding the RF signal. x , G y and G z Specifically, the gradient coil unit 106 includes three gradient coil systems, each of which generates a gradient magnetic field tilted to one of the three spatial axes (e.g., axes x, y, and z perpendicular to each other) of the MRI machine 101 and generates a gradient field in the direction of each axis. The gradient coil driver unit 130 includes three systems (not shown) of driver circuits corresponding to the three gradient coil systems included in the gradient coil unit 106.

[0038] For example, typically, the three spatial axes include a z-axis extending laterally along the length of the subject 120 positioned on the table 110 within the imaging space 120 (e.g., in a direction from the subject's head to the subject's feet), an x-axis extending in a direction flush with the surface of the table 110 (e.g., from the left side to the right side of the subject), and a y-axis extending perpendicularly from the surface of the table 110 (e.g., from the back side to the front side of the patient 118). The corresponding magnetic field gradient G x , G y and G z It is used to spatially encode the RF signal relative to the three axes x, y, and z of the MRI machine 100. This involves using a gradient to determine and position the signal relative to a specific cross-sectional slice of the body being imaged relative to one of the three axes. This gradient is called a slice selection gradient and is usually corresponding to the z axis and therefore corresponds to G zA second gradient is used to frequency encode the signal along another axis or direction, referred to as the frequency encoding direction (e.g., typically the x-axis or the y-axis), and a third gradient is used to phase encode the signal along the remaining axis or direction, referred to as the phase encoding direction (e.g., typically the x-axis or the y-axis). To this end, the specific axes used as the slice selection axis, the frequency encoding axis, and the phase encoding axis, and therefore the gradients, are defined prior to signal acquisition and may vary depending on the desired viewing angle of the anatomy being scanned and various additional factors.

[0039] To selectively excite a specific slice of the subject 118, the gradient coil unit 106 applies a slice-selective gradient magnetic field to the main magnetic field B0 along a slice-selective direction (typically the z-direction) via a corresponding gradient coil system. The RF system also applies slice-selective RF pulses perpendicular to the direction of the slice-selective gradient. The frequency of the RF pulses is tuned to match the resonant frequency of the protons in the desired slice. The RF pulses are typically applied for a specific duration and amplitude. The RF pulses cause the protons in the selected slice to absorb energy and transition from their low-energy state to a higher-energy state. This process is called excitation. Protons outside the selected slice do not resonate with the RF pulse frequency and therefore do not absorb energy. After applying the RF pulses, the slice-selective gradients are reversed. This reverses the precession frequency of the protons in the selected slice, effectively re-phasing them. Once the protons in the selected slice are re-phased, the gradient coil unit 106 applies magnetic field gradients in the frequency-encoding and phase-encoding directions to spatially encode the signal relative to additional axes (e.g., typically the x-axis and y-axis).

[0040] In this regard, in connection with reconstructing a 2D image from acquired signal data defined by a 2D array of pixels having dimensions xy, a frequency encoding gradient is used to determine a signal corresponding to each location along one dimension of the image (e.g., the x or y dimension), and a phase encoding gradient is used to determine a signal corresponding to each location along the other dimension of the image (e.g., the x or y dimension). Frequency encoding is achieved using a gradient magnetic field along one axis (typically the x-axis or readout direction). This gradient causes a change in the resonant frequency of the RF signal emitted by the proton nuclei, thereby allowing spatial information to be encoded along that axis. Phase encoding is achieved using a gradient magnetic field along the other axis (typically the y-axis or phase encoding direction). This gradient causes a change in the phase of the RF signal emitted by the proton nuclei, thereby allowing additional spatial information to be encoded along that axis. During data acquisition, multiple phase encoding steps are performed to sample the signal along the phase encoding direction. Each phase encoding step corresponds to a different strength or duration of the phase encoding gradient, resulting in a different phase shift in the emitted RF signal. By acquiring data using different phase encoding steps, a series of lines, or "k-space lines," are sampled along the phase encoding direction. The number of phase encoding steps corresponds to the number of pixels included in the reconstructed image along one dimension of the image (e.g., the x-dimension or the y-dimension). The number of phase encoding steps also controls the duration required to obtain the signal data needed to create a 2D image of the imaged body slice. Thus, depending on the particular region of the body being imaged, the phase encoding direction can be selectively selected to correspond to the x-axis or the y-axis, whichever requires the least number of phase encoding steps to cover the imaged anatomical structure along the corresponding direction.

[0041] The RF system of the MRI machine 101 includes an RF body coil unit 108 and / or one or more local RF coil arrays 112, 114, and 116. Based on control signals from the operating device 102, the RF driver unit 128 applies an RF pulse sequence for performing a 2D scan to the RF body coil unit 108 and / or one or more local coil arrays 112, 114, and 116 to execute a prescribed RF pulse sequence. The RF signals detected / transmitted by the RF body coil unit 108 and / or one or more local coil arrays 112, 114, and 116 are received by the data acquisition unit 126. The RF system includes at least one transmit RF coil for generating various RF pulses used in MRI pulse sequences, and at least one receive coil for receiving the responsive MR signals for relaying to the data acquisition unit 126 (e.g., via an RF port interface 122 and a T / R switch 124). The transmit RF coil generates one or more RF pulses of a desired frequency, phase, and pulse amplitude waveform in response to a prescribed scan defined by a prescribed RF waveform and an indicated direction.

[0042] According to MRI system 100, MRI machine 101 includes three local RF coil arrays 112, 114, and 116. The local RF coil arrays are arranged, for example, to surround a region to be imaged of a subject 118. In a static magnetic field space or imaging space 120, where a main magnetic field B0 is formed by a static magnetic field magnet unit 104, local RF coil arrays 112, 114, and 116 can transmit initial RF pulses, which are electromagnetic waves, to subject 118 based on control signals from operating device 102, thereby generating a high-frequency magnetic field B1. This excites proton spins in the slice of subject 118 to be imaged. Local RF coil arrays 112, 114, and 116 can also transmit one or more additional refocusing RF pulses depending on a prescribed pulse sequence. The local RF coil arrays receive the electromagnetic waves generated when proton spins return to alignment with the initial magnetization vector after each refocusing pulse as RF signals. In one embodiment, the local RF array coils can use the same local RF coil for both transmitting and receiving RF array pulses. In another embodiment, one or more local RF coil arrays may be used to receive only MR signals, but not to transmit RF pulses.One or more RF coil arrays 112, 114, and / or 116 may be coupled to the table 110 and move with the table.

[0043] The RF body coil unit 108 is arranged, for example, to surround an imaging space 120 and generates RF magnetic field pulses B1 within the imaging space 120 that are orthogonal to the main magnetic field B0 generated by the static field magnet unit 104 to excite nuclei. In contrast to local RF coil arrays (such as local RF coil arrays 112, 114, and 116), which can be easily disconnected from the MRI machine 101 and replaced with another local RF coil, the RF body coil unit 108 is fixedly attached and connected to the MRI machine 101. Furthermore, while local coil arrays can transmit or receive signals only from a local region of the subject 118, the RF body coil unit 108 generally has a larger coverage area and can be used to transmit or receive signals to the entire body of the subject 118. Using a receive-only RF coil array and a transmit body coil provides uniform RF excitation and good image uniformity, but at the expense of high RF power deposited in the subject. With a transmit-receive RF coil array, the coil array provides RF excitation to the region of interest and receives MR signals, thereby reducing RF power deposited in the subject. It will be appreciated that the specific use of the local RF coil arrays 112 , 114 , and 116 and / or the RF body coil unit 108 depends on the imaging application.

[0044] When operating in a receive mode, the T / R switch 124 can selectively electrically connect the RF body coil unit 108 to the data acquisition unit 126 (e.g., via the RF port interface 122), and when operating in a transmit mode, the T / R switch can selectively electrically connect the RF body coil unit to the RF driver unit 128. Similarly, when the local RF coil arrays are operating in a receive mode, the T / R switch 124 can selectively electrically connect one or more of the local RF coil arrays 112, 114, and / or 116 to the data acquisition unit 126 (e.g., via the RF port interface 122), and when operating in a transmit mode, the T / R switch can selectively electrically connect one or more of the local RF coil arrays to the RF driver unit 128. When both the local RF coil arrays 112, 114, and / or 116 and the RF body coil unit 108 are used for a single scan, for example, if the local RF coil arrays are configured to receive MR signals and the RF body coil unit 108 is configured to transmit RF signals, the T / R switch 124 can direct control signals from the RF driver unit 128 to the RF body coil unit 108 via the RF port interface 122, while simultaneously directing received MR signals from the local RF coil arrays 112, 114, and / or 116 to the data acquisition unit 126. The RF body coil unit 108 can be configured to operate in a transmit-only mode, a receive-only mode, or a transmit-receive mode. The local RF coil arrays 112, 114, and / or 116 can be configured to operate in a transmit-receive mode or a receive-only mode.

[0045] The RF driver unit 128 may include a gate modulator, an RF power amplifier, and an RF oscillator (not shown), which are used to drive the RF coil array and form a high-frequency magnetic field in the imaging space 120. The RF driver unit 128 modulates the RF signal received from the RF oscillator into a signal with a predetermined envelope and predetermined timing using the gate modulator based on a control signal from the controller unit operating device 102. The RF signal modulated by the gate modulator may be amplified by the RF power amplifier and then output to the RF coil array.

[0046] The data acquisition unit 126 includes a preamplifier, a phase detector, and an analog / digital converter, and is used to acquire response RF signals received by the local RF coil arrays 112, 114, and 116 and / or the RF body coil unit 108. In the data acquisition unit 126, the phase detector uses the output of the RF oscillator from the RF driver unit 128 as a reference signal to perform phase detection on the signals received from the RF coil array and / or the RF body coil unit 108 and amplified by the preamplifier, and outputs the phase-detected analog magnetic resonance signals to the analog / digital converter for conversion into digital signals. The digital signals obtained in this manner are output to the operating device 102 for image reconstruction processing.

[0047] Figure 2 An exemplary operating device 102 of an MRI system 100 is presented that facilitates controlling the acquisition of 2D MRI images by an MRI machine 101 using a combination of a VERSE protocol and an along-slice flow compensation protocol, in accordance with one or more embodiments of the disclosed subject matter. Figure 1 and Figure 2 , embodiments of the systems described herein (e.g., MRI system 100, etc.) may include one or more machine-executable or computer-executable components embodied within one or more machines (e.g., embodied in one or more computer-readable storage media associated with one or more machines). Such components, when executed by one or more machines (e.g., processors, computers, computing devices, virtual machines, etc.), may cause the one or more machines to perform the described operations.

[0048] For example, the operating device 102 includes several machine / computer-executable components 202, including (but not limited to) a control component 204, a configuration component 206, a reconstruction component 212, and a rendering component 214. These computer / machine-executable components 202 may be stored in (at least one) memory 218 of the operating device 102, which may be coupled to (at least one) processing unit 220 (or processor) for execution thereof. Generally, the control component 204 may control the acquisition of MR signal data associated with an anatomical region of the subject 118 via the MRI machine 101 according to defined acquisition protocols and parameters provided by the configuration component 206. According to the disclosed technology, the configuration component 206 may configure (and / or facilitate configuration based in part on user input provided by an operating technician) a specific acquisition protocol and parameters that control the acquisition of signal data according to a 2D spin echo sequence that incorporates a combination of a VERSE protocol and an along-slice flow compensation protocol. The reconstruction component 212 can reconstruct an image of the anatomical region from the acquired signal data according to the employed acquisition protocol and acquisition parameters, and the rendering component 214 can render the image via an electronic display coupled to the operating device 102 .

[0049] The operating device 102 may also include one or more input / output devices 222 that facilitate receiving user input and / or presenting output data to a user to coordinately control the operation of the MRI machine 101 and generate MR images. For example, the one or more input / output devices 222 may include an electronic display via which a control graphical user interface (GUI) may be presented (e.g., via the rendering component 214) to an operating technician of the MRI machine 101, who controls the execution of an MRI scan of the subject 118 to obtain one or more 2D images of an anatomical region of interest of the subject 118. Images reconstructed based on signal data acquired from the scanned region of the subject 118 via the MRI machine 101 (e.g., via the data acquisition unit 126) (e.g., via the reconstruction component 212) may also be presented via the control GUI (e.g., via the presentation component 218). The input / output device 222 may also include any suitable input device (e.g., a keyboard, mouse, touch screen, etc.) that enables an operator to provide input via a control GUI that controls the operation of the MRI machine 101, such as user input to select / set specific slices and / or anatomical regions to be scanned and imaged, user input to select / set one or more acquisition protocols and / or parameters to be applied to the scan, and the like.

[0050] The operating device 102 may also include a system bus 216 that communicatively and operatively couples a memory 218, a processing unit 220, and an input / output device 222 to one another. Examples of the memory 218, the processing unit 220, the input / output device 222, and other suitable computer or computing-based components may be found in the accompanying drawings. Figure 11 Find and combine to achieve combination Figure 2 or use with the systems or components shown and described in other figures disclosed herein.

[0051] According to various embodiments, control component 204 controls the operation of MRI machine 101 according to instructions provided by configuration component 206. To this end, configuration component 206 can determine, define, and / or configure (e.g., based in part on operator input received via a control GUI) a specific acquisition protocol and / or acquisition parameters to be applied by MRI machine 101 for acquiring signal data associated with an anatomical region of subject 118. In 2D MRI, an anatomical region can correspond to one or more cross-sectional regions of the subject. For example, when applied to multi-slice imaging, an anatomical region can correspond to a volumetric region of subject 118 from which multiple cross-sectional 2D image slices are acquired. Using these embodiments, configuration component 206 can define a discrete 2D spin echo sequence customized for each slice. Control component 204 can then control the acquisition of signal data by MRI machine 101 according to the configured acquisition protocol and / or acquisition parameters defined for each slice. For example, the control component 204 can direct (e.g., via one or more control signals transmitted by the control component 204 to the data acquisition unit 126, the RF driver unit 128, and the gradient driver unit) the MRI machine 101 to acquire MR signal data from each selected slice (or portion thereof) according to a corresponding 2D MRI sequence defined for each slice.

[0052] In various embodiments, the specific acquisition protocol and / or acquisition parameters configured by the configuration component 206 and applied by the control component 204 can include a combination of a VERSE protocol and an along-slice flow compensation protocol along with a standard 2D MRI spin echo procedure. To facilitate this, the configuration component 206 can include, but is not limited to, an acquisition setup component 208 and a sequence component 210.

[0053] In one or more embodiments, the acquisition setup component 208 can facilitate receiving user input associated with configuring an acquisition protocol and / or acquisition parameters to be applied to an MRI scan. In this regard, the acquisition setup component 208 can correspond to an interactive control application that enables an MRI operator to input information associated with configuring an acquisition protocol and / or acquisition parameters to be applied to an MRI scan based on the acquisition capabilities of the MRI system 100. For example, in association with establishing an MRI scan, the acquisition setup component 208 can enable an operator to select an appropriate MRI scan protocol and acquisition parameters based on the patient's clinical indications and desired imaging parameters. This can include selecting the type of MRI sequence (e.g., TE, FSE, TSE, T1-weighted, T2-weighted, diffusion-weighted), scan planes (e.g., axial, sagittal, coronal), setting slice selection, frequency and phase encoding directions, and other acquisition parameters (e.g., field of view, slice thickness, matrix size).

[0054] For example, in some implementations, in connection with establishing a multi-slice acquisition, the acquisition setup component 208 can enable a technician to specify the location and orientation of the slices to be acquired. This can involve manually specifying the number of slices, their thickness, spacing, and orientation relative to the patient's anatomy. Additionally or alternatively, the acquisition setup component 208 can automatically define these parameters based on the selected volumetric region of the patient to be scanned and the desired scan plane.

[0055] In association with setting up an MRI scan, the acquisition setup component 208 may also enable the operating technician to provide input for selecting an appropriate scan protocol and sequence configuration parameters for the MRI scan sequence. For example, the acquisition setup component 208 may provide for selecting the type of MRI sequence to be applied. For multi-slice imaging, a 2D MRI sequence that allows acquisition of multiple slices in a single scanning session, such as an FSE sequence or a TSE sequence, is typically used. In another example, the acquisition setup component 208 may provide for receiving user input for defining parameters for controlling gradient and RF pulse sequence configuration. According to some embodiments of the disclosed technology, this may involve selecting whether to apply a combination of the disclosed VERSE protocol and a flow compensation protocol along the slice. In some specific implementations, the acquisition setup component 208 may also provide setup parameters such as slice selection gradients, frequency and phase encoding gradients, RF pulse timing and shape, and other sequence-specific parameters.

[0056] Additionally or alternatively, the sequence component 210 can automatically determine and / or define parameters controlling the configuration of gradient and RF pulse sequences based on the selected MRI sequence type, the region of the anatomy being imaged, the specified location and orientation of the slice, and the selected additional protocol to be applied. For example, in various embodiments, based on the specified slice and receipt of user input via the acquisition setup component 208, selection of application of the disclosed combination of VERSE and along-slice flow compensation protocols, and a selected 2D spin echo sequence (e.g., an FSE sequence or another type of spin echo sequence), the sequence component 210 can automatically configure the gradient and RF pulse sequence configuration accordingly. In still other embodiments, the acquisition setup component 208 can automatically apply a combination of the VERSE protocol and along-slice flow compensation protocol based on the selected sequence type corresponding to the spin echo sequence, the specific region of the body being imaged (and / or other predefined criteria), and the sequence component 210 can configure the gradient and RF pulse sequences accordingly.

[0057] In this regard, according to various embodiments, in conjunction with the use of a 2D spin echo sequence for acquiring signal data from a 2D MRI scan, the sequence component 210 can determine, define, configure, and / or control MRI sequence parameters for the 2D spin echo sequence based on a combination of an along-slice flow compensation protocol and a VERSE protocol. To this end, the VERSE protocol and the along-slice flow compensation protocol involve tailoring the slice-selective gradient waveform in different ways to achieve different objectives. For example, as described in the background section, conventional along-slice flow compensation involves tailoring the slice-selective gradient waveform to account for motion in the slice direction. By carefully defining parameters that control the shape and timing of the gradient pulses in the slice-selective direction, it is possible to eliminate or minimize the effects of motion-induced phase shifts in the slice direction. The employed VERSE protocol involves reducing the amount of RF power associated with signal acquisition, and thus reducing the SAR associated with the signal acquisition, by reducing the peak amplitude of the RF pulse by a certain scaling factor and reshaping the corresponding slice-selective gradient waveform based on the scaling factor to excite the same slice. According to the disclosed technology, the sequence component 210 optimizes the slice-selective gradient waveform in a manner that achieves both of these objectives.

[0058] In this regard, Figure 3A and Figure 3B Exemplary FSE sequence waveforms according to along-slice flow compensation with and without VERSE are presented in accordance with one or more embodiments of the disclosed subject matter. Figure 3A An exemplary FSE sequence waveform 300A is presented according to a flow compensation protocol along a slice and without a VERSE protocol definition. Figure 3B An exemplary FSE sequence waveform 300B defined according to the along-slice flow compensation protocol and the VERSE protocol is presented.

[0059] Given that Figure 1-Figure 2 refer to Figure 3A and Figure 3B , Figure 3A and Figure 3BThe FSE sequence waveforms shown in FIG 1 graphically represent FSE sequence parameters defining the x- and z-gradient pulse sequences and the RF pulse sequence, respectively. For the sake of brevity, the y-gradient pulse sequence is omitted. To this end, the RF pulse sequences (e.g., Sequence 3A and Sequence 3B) define, as a function of time (in milliseconds (ms)) and amplitude, the RF pulse sequence to be applied to acquire signals associated with a selected slice of the imaged subject 118. According to this example, RF1 corresponds to the initial excitation pulse of the FSE sequence, and RF2 corresponds to the initial refocusing pulse. Additional RF pulses (e.g., RF3, RF4, RF5, etc.) correspond to additional refocusing RF pulses of the echo train. It should be understood that for the sake of brevity, only a portion of the echo train is shown, and the echo train length may vary. The gradient pulse sequence defines the timing of application of the respective x- and z-direction gradient pulses as a function of time and gradient amplitude.

[0060] According to waveforms 300A and 300B, the z-direction gradient waveforms, i.e., sequences 2A and 2B, respectively, correspond to slice-selective gradient waveforms. Therefore, according to sequences 2A and 2B, each distinct linear segment extending above and below the baseline gradient amplitude corresponds to the pulsed application of a Gz gradient magnetic field, i.e., a slice-selective gradient. Therefore, each distinct linear segment is defined by a different gradient waveform having a different shape, wherein the different shapes correspond to a method for applying a Gz magnetic field for adjusting and maintaining its applied strength / amplitude (e.g., measured in mT / m) for a short duration (e.g., typically less than a few milliseconds).

[0061] The slice selection gradient pulses are temporally aligned with the RF pulses of the RF pulse sequence. For example, the different slice selection gradient pulses are referred to as GZRF1, GZRF2, GZRF3, GZRF4, GZRF5, etc., to indicate that the corresponding gradient pulses correspond to Gz gradient pulses applied synchronously with the timing of RF1, RF2, RF3, RF4, RF5, etc. For this purpose, GZRF1 corresponds to the excitation gradient timed with the application of the initial excitation pulse RF1, and GZRF2 corresponds to the initial refocusing gradient timed with the application of the initial refocusing pulse RF2. For this purpose, in accordance with the illustrated FSE sequence and other sequences, reference may be made to a slice selection gradient waveform (e.g., Sequence 2A and Sequence 2B) that includes a plurality of different slice selection gradients (e.g., GZRF1, GZRF2, GZRF3, GZRF4, GZRF5, etc.).

[0062] According to the disclosed flow compensation protocol along a slice, the slice selection gradient waveform also includes a rephasing gradient (GZ1) applied between the excitation gradient (GZRF1) and the refocusing gradient (GZRF2). The rephasing gradient GZ1 (also known as the rewind gradient or crushing gradient) is used to compensate for phase shifts caused by flowing material (such as blood flow) during signal acquisition. The rephasing gradient GZ1 is used to rephases the magnetic moments of protons within the slice and helps reduce or eliminate undesirable phase shifts caused by flowing material (as well as magnetic field inhomogeneities and motion), thereby minimizing flow artifacts in images reconstructed using the acquired signal data. The rephasing gradient GZ1 has opposite polarity and intensity to the slice selection gradient GZRF1 and the refocusing gradient GZRF2. By applying an appropriate rephasing gradient tailored to the direction and velocity of the flow, flow-related artifacts in the resulting image can be minimized or eliminated, thereby improving image quality and diagnostic accuracy.

[0063] According to the subject VERSE protocol, the peak amplitude of the RF pulse is reduced relative to the peak amplitude that would be applied in the absence of the contrast protocol. For example, as can be seen by comparing sequence 3A with sequence 3B, the peak value of the RF pulse in sequence 3A (without VERSE applied) is substantially greater (and therefore stronger in amplitude / power) relative to the peak value of the RF pulse in sequence 3B. To this end, in association with applying the VERSE protocol, the sequence component 210 scales down the peak amplitude of the RF pulse by a specific scaling factor (e.g., as predefined and / or customized based on operator input). The sequence component 210 also reshapes the corresponding slice selection gradient waveform based on the scaling factor to excite the same slice. In association with reshaping the slice selection gradient waveform, the VERSE protocol also controls the shape of the slice selection gradient waveform to be defined by an initial peak, followed by a steady hold at a lower amplitude, followed by another ending peak.

[0064] In this regard, Figure 4A and Figure 4B A close-up view of the relevant slice selection gradients for sequence 3A and sequence 3B is presented, according to one or more embodiments of the disclosed subject matter. To this end, the relevant slice selection gradients include three initial slice selection gradients, including an excitation gradient (GZRF1), a refocusing gradient (GZRF2), and a slice rephasing gradient (GZ1). Figure 4A A magnified view of three gradients 400A as extracted from sequence 2A is presented. Figure 4B A magnified view of three gradients 400B as extracted from sequence 2B is presented.

[0065] As can be seen from a comparison of the waveform shapes of the three gradients 400A with those of the three gradients 400B, the shapes of the slice-selective gradients GZRF1 and GZRF2 defined according to flow compensation along the slice only differ from those defined according to both VERSE and flow compensation along the slice. Therefore, according to flow compensation along the slice without VERSE, the shapes of GZRF1 and GZRF2 are rectangular or substantially rectangular. However, according to the VERSE protocol, the shapes of GZRF1 and GZRF2 are, by comparison, non-rectangular or substantially irregular. Specifically, as shown in the enlarged view of the three gradients 400B, according to the VERSE protocol, the waveforms of both GZRF1 and GZRF2 are defined by two terminal peaks separated by a constant flat region. For example, with respect to GZRF1, the corresponding peaks are referred to as the left and right peaks of GZRF1 and are labeled L1 and R1, respectively, and with respect to GZRF2, the corresponding peaks are referred to as the left and right peaks of GZRF2 and are labeled L2 and R2, respectively. In one or more specific implementations, the corresponding left peak is referred to as the rephasing peak and the right peak is referred to as the crushing peak. In this regard, similar to the slice rephasing gradient GZ1, these peaks facilitate the rephasing of the magnetic moments of protons within the slice in a manner that ensures accurate image formation and reduces artifacts. These peaks have opposite polarity and intensity compared to the middle portions of the corresponding gradients GZRF1 and GZRF2.

[0066] According to the disclosed flow compensation protocol along a slice, the sequence component 210 applies and defines the slice rephasing gradient (GZ1) waveform parameters based on the waveform parameters defining the excitation gradient (GZRF1) and the refocusing gradient (GZRF2). This involves determining the waveform parameters defining the respective waveforms of the excitation gradient (GZRF1) and the refocusing gradient (GZRF2) based on the geometry of the respective waveforms relative to the baseline and the respective regions defined by the geometry. Because the shapes of GZRF1 and GZRF2 without VERSE (e.g., as shown with respect to 400A) are substantially rectangular, the calculation of these waveform parameters and the optimization of GZ1 based thereon is relatively straightforward, as shown in FIG. Figure 5 However, associated with the combination of flow compensation along a slice with a VERSE waveform, the sequence component 210 cannot directly and accurately calculate these parameters based on the irregular shapes of GZRF1 and GZR2 generated by the VERSE protocol. Therefore, in various embodiments, to enable flow compensation along a slice with a VERSE gradient waveform, the sequence component 210 converts these gradients into equivalent rectangular shapes (corresponding to those of 400A), as shown. Figure 6Using these rectangles to model the region under the VERSE gradient, the sequence component then calculates reference gradient waveform parameters and uses these reference gradient parameters to determine and define the slice rephasing gradient GZ1.

[0067] For example, Figure 5 The relevant waveform parameters defining the excitation gradient (GZRF1) and the refocusing gradient (GZRF2) are shown, as extracted from a rectangular shaped version of the corresponding gradient waveform as included in sequence 2A. In particular, Figure 5 A magnified view of portion 400A-1 of the excitation gradient (GZRF1) shown in the corresponding dashed box of view 400A and a magnified view of portion 400A-2 of the refocusing gradient (GZRF2) shown in the corresponding dashed box of view 400A are presented. According to a flow compensation protocol along a slice in which VERSE is not applied, portion 400A-1 of GZRF1 and portion 400A-2 of GZRF2 are rectangular or substantially rectangular. In this regard, the respective portions are defined by a rectangular volume having right triangles defined on its sides. The waveform parameters defining GZRF1 used by sequence component 210 to determine GZRF1 include a_gzrf1 (corresponding to the height of the rectangular volume of GZRF1), iso_delay (corresponding to the length of the rectangular volume of GZRF1), and pw_gzrf1d (corresponding to the length of the right triangle portion of GZRF1). The sequence component 210 also calculates the area defined by the shape of GZRF1 based on these parameters and determines the rephasing gradient GZ1 based on the area of ​​GZRF1. The waveform parameters that the sequence component 210 uses to determine GZ1 and define GZRF2 include a_gzrf2 (corresponding to the height of the rectangular body of GZRF2), pw_gzrf2 / 2 (corresponding to the length of the rectangular body GZRF2), and pw_gzrf2a (corresponding to the length of the right-angled triangle portion of GZRF2). The sequence component 210 also calculates the area defined by the shape of GZRF2 based on these parameters and determines the rephasing gradient GZ1 based on the area of ​​GZRF2.

[0068] For example, Figure 6 The irregularly shaped VERSE gradient of sequence 2B is converted to rectangular shapes corresponding to portions 400A-1 and 400A-2, and the parameters for defining the VERSE gradient of the rephasing gradient GZ1 are determined according to a combined VERSE and flow compensation protocol along the slice. To this end, FIG6 presents an enlarged view of portion 400B-1 of the excitation gradient (GZRF1) shown in the corresponding dashed box of view 400B, and an enlarged view of portion 400B-2 of the refocusing gradient (GZRF2) shown in the corresponding dashed box of view 400B.

[0069] As shown with respect to section 400B-1, the irregularly shaped waveform of the VERSE-defined gradient of GZRF1 may be defined by parameters a_gzfr1 (corresponding to the peak height of R1), iso_delay (corresponding to the length of the body of GZRF1), and pw_gzrf1d (corresponding to the length of the right triangle portion of GZRF1). As shown with respect to section 400B-2, the irregularly shaped waveform of the VERSE-defined gradient of GZRF2 may be defined by parameters a_gzfr2 (corresponding to the peak height of L1), pw_gzrf2 / 2 (corresponding to the length of the body of GZRF2), and pw_gzrf2a (corresponding to the length of the right triangle portion of GZRF2).

[0070] According to various embodiments, the sequence component 210 models the irregularly shaped waveforms of GZRF1 and GZRF2 defined according to the VERSE protocol as Figure 5 There is no corresponding rectangular version of the VERSE protocol shown in . For example, Figure 6 As shown, this may involve converting the shape of portion 400B-1 to the rectangular shape of portion 600B-1 and converting the shape of portion 400B-2 to the rectangular shape of portion 600B-2. The sequence component 210 also redefines the waveform parameters associated with GZRF1 and GZRF2 based on the modeling version. In this regard, as shown in FIG. Figure 6 As shown, using the modeled portions 600B-1 and 600B-2, the sequence component 210 determines reference parameters corresponding to the estimated values ​​of the parameters shown with respect to portions 400B-1 and 400B-2. For example, based on the modeled rectangular shape of portion 600B-1, the sequence component 210 determines updated waveform parameters for a_gzrf1 (now referred to as a_gzrf1'), updated parameters for iso_delay (now iso_delay'), and updated parameters for pw_gzrf1d (now pw_gzrf1d'). The sequence component 210 also determines the geometric region defined by the modeled version of GZRF1 based on the updated parameters. Likewise, based on the modeled rectangular shape of portion 600B-2, the sequence component 210 determines updated waveform parameters for a_gzrf2 (now referred to as a_gzrf2′), updated parameters for pw_gzrf2a (now pq_gzrf2a′), and updated parameters for pw_gzrf2 / 2 (now pw_gzrf2 / 2′). The sequence component 210 also determines the geometric region defined by the modeled version of GZRF2 based on the updated parameters.

[0071] Sequence component 210 then defines waveform parameters for the rephasing gradient GZ1 using the calculated area and reference parameters determined based on the modeled versions of GZRF1 and GZRF2. However, in connection with configuring a 2D FSE sequence to be applied to signal acquisition, sequence component 210 does not use the modeled versions of GZRF1 and GZRF2. In this regard, sequence component 210 uses the original versions of GZRF1 and GZRF2 defined according to the VERSE protocol, which have waveform parameters shown with respect to portions 400B-1 and 400B-2 based on their irregularly shaped waveforms.

[0072] According to the above reference Figure 3A-Figure 5 In the depicted embodiment, the VERSE protocol applied by the sequence component 210 corresponds to a linear VERSE protocol. In this regard, according to the linear VERSE protocol, although the shapes of the excitation gradient GZRF1 and the refocusing gradient GZRF2 are non-rectangular or irregular, they are defined by straight lines as opposed to curved lines. For example, Figure 7 An exemplary VERSE slice selection gradient 700 according to the nonlinear VERSE protocol is presented. Figure 7 As shown, according to the nonlinear VERSE protocol, the waveform shapes of the excitation gradient GZRF1 and the refocusing gradient GZRF2 are defined by irregular shapes including curved lines. In various embodiments, the use of linear VERSE as opposed to nonlinear VERSE enables the use of linear VERSE according to the above reference. Figure 6 The described techniques efficiently and accurately estimate the waveform parameters and area defined by the resulting gradient. For example, while the ability to accurately and efficiently model an irregularly shaped gradient defined according to nonlinear VERSE into an equivalent rectangular version (e.g., corresponding to sections 400A-1 and 400A-2) is significantly hampered by the curvature of its waveform, the use of linear VERSE as opposed to nonlinear VERSE enables sequence component 210 to efficiently and accurately define the rephasing gradient GZ1 associated with integrating a flow compensation protocol along a slice with VERSE.

[0073] Figure 8 Exemplary MRI images acquired using different acquisition protocols according to one or more embodiments of the disclosed subject matter are presented. In particular, Figure 8Exemplary MRI images of cross-sectional views of a subject's spine sliced ​​according to the slice view angle shown in image 800 (where the slice view angle corresponds to a plane defined by a white line drawn relative to image 800) are presented. For this purpose, images 801, 802, and 803 each correspond to an axial C-spine image. Each MRI image was acquired using a 2D FSE sequence via an MRI system corresponding to system 100. Image 801 corresponds to an image acquired according to the disclosed along-slice flow compensation protocol. Image 802 corresponds to an image acquired according to a combination of the disclosed VERSE and along-slice flow compensation protocols, and image 803 corresponds to an image acquired using a 2D FSE sequence without along-slice flow compensation and without VERSE.

[0074] As can be seen via a comparison of image 803 and image 802, image 803 includes flow artifacts, while image 803 excludes flow artifacts, thereby demonstrating how the disclosed combined VERSE and along-slice flow compensation protocol can be used to successfully minimize or eliminate flow artifacts. For example, the flow artifacts included in image 803 correspond to flow voids that were completely removed from image 802. Additionally, while along-slice flow compensation alone can result in minimizing the same flow artifacts as demonstrated via image 801, the RF power used for the RF pulse sequence during signal acquisition is significantly higher without the VERSE protocol. Thus, the combined VERSE and along-slice flow compensation protocol used to acquire image 802 results in reduced SAR compared to the acquisition protocol and acquisition parameters used to acquire image 801.

[0075] Figure 9 A high-level flowchart of an exemplary computer-implemented method 900 for performing an MRI scan using a combination of a VERSE protocol and an along-slice flow compensation protocol, in accordance with one or more embodiments of the disclosed subject matter, is presented. Method 900 includes, at 902, determining, by a device including a processor (e.g., operating device 102), a 2D spin echo sequence suitable for acquiring signal data associated with a slice of an anatomical region of a subject via an MRI system (e.g., MRI system 100), wherein determining the 2D spin echo sequence includes determining the 2D spin echo sequence according to a combination of a VERSE protocol and an along-slice flow compensation protocol (e.g., via sequence component 210). At 904, method 900 includes controlling, by the device, the MRI system to acquire the signal data using the 2D spin echo sequence (e.g., via control component 204). At 906, method 900 includes reconstructing, by the device, an image of the slice from the signal data (e.g., via reconstruction component 212).

[0076] To this end, according to method 900, based on employing the combination, the image comprises a defined image quality, and the SAR of the acquisition is reduced relative to another similar acquisition using a similar 2D spin echo sequence defined according to a flow compensation protocol along the slice but without the VERSE protocol. In this regard, the defined image quality includes the absence of flow artifacts or the amount of flow artifacts being less than a defined amount due to the flow compensation protocol along the slice. For example, in various implementations, the spin echo sequence employed according to method 900 corresponds to the sequence defined by waveform 300B. Compared to the spin echo sequence defined by waveform 300B with flow compensation but without VERSE, the RF pulses of the RF sequence are significantly reduced, thereby reducing the SAR associated with the acquisition. As applied in conjunction with the acquisition of multiple slices, the aggregate reduction in SAR of a multi-slice scan incorporating the combination of VERSE and flow compensation along the slice can provide substantial clinical benefits while also optimizing image quality with respect to the elimination or reduction of flow artifacts.

[0077] Figure 10 A high-level flowchart of an exemplary computer-implemented method 1000 for performing an MRI scan using a combination of a VERSE protocol and an along-slice flow compensation protocol in accordance with one or more embodiments of the disclosed subject matter is presented. The method 1000 includes, at 1002, defining, by a device including a processor (e.g., operating device 102), (e.g., via sequence component 210), a first slice-selective gradient waveform for a 2D spin echo sequence applicable to acquiring signal data associated with a slice of an anatomical region of a subject via an MRI system (e.g., MRI system 100), including determining, according to the VERSE protocol, the first slice-selective gradient waveform based on a scaling factor of a peak amplitude of a radio frequency pulse used to define the 2D spin echo sequence, wherein the first slice-selective gradient waveform is defined by a first shape.

[0078] In this regard, reference Figures 1-10 , the first slice selection gradient may correspond to the initial excitation gradient GZRF1 and the initial refocusing gradient GZRF2. Figure 3B 、 Figure 4B and Figure 6 As described, in connection with defining these slice selection gradients according to the VERSE protocol, the shapes of the waveforms defining these gradients are non-rectangular and / or irregular compared to the same gradients defined according to flow compensation without VERSE. In this regard, the shapes of these first slice selection gradient waveforms correspond to Figure 4B and the shape shown in view 400B.

[0079] Continuing with method 1000, at 1004, method 1000 includes generating, by the device (eg, via sequence component 210), a modeled version of the first slice selection gradient waveform having a second shape that is more rectangular relative to the first shape 1004, as shown in FIG. Figure 6 At 1006, method 1000 includes determining, by the device (e.g., via sequence component 210), parameters associated with a first slice selection gradient waveform based on the modeled version. For example, as described in reference Figure 6 As described, this corresponds to determining reference parameters, which correspond to the updated parameters a_gzrf1′, iso_delay′, pw_gzrf1d′, etc., for the regions defined by the modeled versions of the gradient waveforms of GZRF1 and GZRF2.

[0080] At 1008, 1000 includes defining, by the device, a second slice selection gradient of the 2D spin echo sequence based on the parameters, the second slice selection gradient being configured to minimize motion-induced phase shifts. For example, this corresponds to the sequence component 210 determining waveform parameters for the rephasing gradient GZ1 based on the updated parameters or reference parameters determined at 1006. In this regard, in various embodiments, based on a combination of applying the disclosed VERSE protocol and the flow compensation protocol along the slice, the sequence component 210 can be configured to first define waveform parameters for the 2D spin echo sequence employed according to the VERSE protocol. In other words, the sequence component 210 can first define the 2D spin echo sequence waveform according to the VERSE protocol. This involves defining an RF pulse sequence waveform using RF pulses having a reduced power distribution (e.g., reduced peak amplitude) relative to a spin echo sequence without the VERSE protocol. This also involves defining slice selection gradients (e.g., GZRF1, GZRF2, GZRF3, etc.) according to the VERSE protocol tailored for the reduced RF pulse amplitude. The sequence component 210 can then define the waveform parameters for the 2D spin echo sequence employed according to the reference protocol. Figure 6 The described technique determines the calculated reference parameters for GZRF1 and GZRF2, defining the rephasing gradient according to a flow compensation protocol along the slice.

[0081] At 1010, method 1000 includes controlling, by the device (e.g., via control component 204), acquisition of signal data via the MRI system according to a 2D spin echo sequence (e.g., as configured by sequence component 210). In this regard, reconstruction component 212 can then reconstruct an image of the slice imaged using the acquired signal data.

[0082] One or more embodiments may be systems, methods, and / or computer program products at any possible level of technical detail of integration. The computer program product may include a computer-readable storage medium (or multiple media) having computer-readable program instructions thereon for causing a processor to perform aspects of the invention.

[0083] A computer-readable storage medium may be a tangible device that can hold and store instructions for use by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of computer-readable storage media includes the following: a portable computer floppy disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disc (DVD), a memory stick, a floppy disk, a mechanical encoding device (such as a punch card or a raised structure in a groove on which instructions are recorded), and any suitable combination of the foregoing. As used herein, a computer-readable storage medium should not be understood as a transient signal itself, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagated through a waveguide or other transmission medium (e.g., a light pulse passing through a fiber optic cable), or an electrical signal transmitted through a wire.

[0084] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to a corresponding computing / processing device, or downloaded to an external computer or external storage device via a network (e.g., the Internet, a local area network, a wide area network, and / or a wireless network). The network can include copper transmission cables, optical transmission fibers, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in a computer-readable storage medium within the corresponding computing / processing device.

[0085] The computer-readable program instructions for performing the operations of the present invention may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, configuration data of an integrated circuit system, or source code or object code written in any combination of one or more programming languages ​​(including object-oriented programming languages ​​such as Smalltalk, C++, etc.), procedural programming languages ​​(such as "C" programming language or similar programming languages), and machine learning programming languages ​​(such as CUDA, Python, Tensorflow, PyTorch, etc.). The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server using suitable processing hardware. In the latter scenario, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In various embodiments involving machine learning programming instructions, the processing hardware may include one or more graphics processing units (GPUs), central processing units (CPUs), and the like. In some embodiments, electronic circuits including, for example, programmable logic circuits, field programmable gate arrays (FPGAs), or programmable logic arrays (PLAs) can execute computer-readable program instructions by utilizing state information of the computer-readable program instructions to personalize the electronic circuits so as to perform aspects of the present invention.

[0086] Various aspects of the present invention are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0087] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device to produce a machine, such that the instructions executed by the processor of the computer or other programmable data processing device create a component for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium, which can direct the computer, programmable data processing device, and / or other equipment to function in a particular manner, such that the computer-readable storage medium having the instructions stored therein comprises an article of manufacture, which includes instructions for implementing various aspects of the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0088] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus, or other device to produce a computer-implemented process, such that the instructions executed on the computer, other programmable apparatus, or other device implement the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0089] The flow charts and block diagrams in the accompanying drawings illustrate the possible specific implementation architecture, function and operation of the system, method and computer program product according to various embodiments of the present invention. In this regard, each frame in the flow chart or block diagram can represent a module, fragment or part of an instruction, which includes one or more executable instructions for realizing a specified logical function. In some alternative implementations, the function indicated in the frame may not occur in the order indicated in the figure. For example, depending on the function involved, two frames of continuous display can actually be performed substantially simultaneously, or the frame can sometimes be performed in reverse order. It will also be noted that the combination of each frame of the block diagram and / or flow chart illustration and the frame in the block diagram and / or flow chart illustration can be implemented by a system based on dedicated hardware that performs a specified function or action or implements a combination of dedicated hardware and computer instructions.

[0090] Combine Figure 9 , the systems and processes described below can be embodied in hardware, such as a single integrated circuit (IC) chip, multiple ICs, an application-specific integrated circuit (ASIC), etc. In addition, the order in which some or all of the program blocks appear in each procedure should not be considered limiting. On the contrary, it should be understood that some program blocks can be executed in various orders, not all of which can be explicitly shown herein.

[0091] refer to Figure 11 An illustrative example environment 1100 for implementing various aspects of the claimed subject matter includes a computer 1102. The computer 1102 includes a processing unit 1104, a system memory 1106, a codec 1135, and a system bus 1108. The system bus 1108 couples system components, including but not limited to the system memory 1106, to the processing unit 1104. The processing unit 1104 can be any of a variety of available processors. Dual microprocessors, one or more GPUs, and other multi-processor architectures can also be used as the processing unit 1104.

[0092] The system bus 1108 may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus or external bus, or a native bus using any of a variety of available bus architectures including, but not limited to, Industry Standard Architecture (ISA), Micro Channel Architecture (MSA), Extended ISA (EISA), Intelligent Drive Electronics (IDE), VESA Native Bus (VLB), Peripheral Component Interconnect (PCI), card bus, Universal Serial Bus (USB), Advanced Graphics Port (AGP), Personal Computer Memory Card International Association (PCMCIA), FireWire (IEEE 11114), and Small Computer System Interface (SCSI).

[0093] In various embodiments, system memory 1106 includes volatile memory 1110 and non-volatile memory 1112, which can employ one or more of the disclosed memory architectures. A basic input / output system (BIOS), which contains basic routines for transferring information between components within computer 1102, such as during startup, is stored in non-volatile memory 1112. Furthermore, according to the present innovations, codec 1135 can include at least one of an encoder or a decoder, wherein at least one of the encoder or decoder can be comprised of hardware, software, or a combination of hardware and software. Although codec 1135 is depicted as a separate component, codec 1135 can be included within non-volatile memory 1112. By way of illustration and not limitation, non-volatile memory 1112 can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), flash memory, 3D flash memory, or resistive memory, such as resistive random access memory (RRAM). In at least some embodiments, the non-volatile memory 1112 can employ one or more of the disclosed memory devices. In addition, the non-volatile memory 1112 can be computer memory (e.g., physically integrated with the computer 1102 or its motherboard) or removable memory. Examples of suitable removable memory that can be used to implement the disclosed embodiments may include secure digital (SD) cards, compact flash (CF) cards, universal serial bus (USB) memory sticks, and the like. The volatile memory 1110 includes random access memory (RAM) that acts as external cache memory, and in various embodiments, one or more of the disclosed memory devices may also be employed. By way of illustration and not limitation, RAM can be provided in a variety of forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), and enhanced SDRAM (ESDRAM).

[0094] The computer 1102 may also include removable / non-removable, volatile / non-volatile computer storage media. Figure 11 Shown is for example disk storage device 1114.Disk storage device 1114 includes but is not limited to the equipment such as disk drive, solid state disk (SSD), flash memory card or memory stick.In addition, disk storage device 1114 can include independent storage medium or the storage medium of other storage medium combination, include but is not limited to CD drive, such as CD ROM device (CD-ROM), CD recordable drive (CD-R drive), CD rewritable drive (CD-RW drive) or digital versatile magneto-optical disk ROM drive (DVD-ROM).In order to help disk storage device 1114 be connected to system bus 1108, removable or non-removable interface, such as interface 1116 is usually used.Should be understood that disk storage device 1114 can store information relevant to user.This type of information can be stored at server or provided to the application program running on server or user equipment.In one embodiment, can notify the user (for example, by output device 1136) the type of information stored in disk storage device 1114 or transferred to server or application program. The user may be provided with an opportunity to opt-in or opt-out of the collection or sharing of such information by the server or application (eg, via input from input device 1128 ).

[0095] It should be understood that Figure 11 Software is described that acts as an intermediary between a user and the basic computer resources described in the appropriate operating environment 1100. Such software includes an operating system 1118. The operating system 1118, which may be stored on disk storage 1114, is used to control and allocate the resources of the computer 1102. Application programs 1120 utilize the operating system 1118's management of resources through program modules 1124 and program data 1126, such as startup / shutdown transaction tables, stored in system memory 1106 or on disk storage 1114. It should be understood that the claimed subject matter can be implemented with various operating systems or combinations of operating systems.

[0096] The user enters commands or information into the computer 1102 through input devices 1128. Input devices 1128 include, but are not limited to, pointing devices such as a mouse, trackball, stylus, touchpad, keyboard, microphone, joystick, game pad, satellite dish, scanner, TV tuner card, digital camera, digital video camera, webcam, etc. These and other input devices are connected to the processing unit 1104 via interface ports 1130 through the system bus 1108. Interface ports 1130 include, for example, serial ports, parallel ports, game ports, and universal serial buses (USB). Output devices 1136 use some of the same types of ports as input devices 1128. Thus, for example, a USB port can be used to provide input to the computer 1102 and output information from the computer 1102 to output devices 1136. Output adapters 1134 are provided to illustrate that there are some output devices 1136 such as monitors, speakers, and printers, as well as other output devices 1136 that require special adapters. By way of illustration and not limitation, output adapters 1134 include video and sound cards that provide a means of connection between output devices 1136 and system bus 1108. It should be noted that other devices or systems of devices provide input and output capabilities, such as remote computer 1138.

[0097] Computer 1102 can operate in a networked environment using logical connections to one or more remote computers, such as remote computer 1138. Remote computer 1138 can be a personal computer, server, router, network PC, workstation, microprocessor-based device, peer device, smartphone, tablet, or other network node, and typically includes many of the elements described with respect to computer 1102. For the sake of simplicity, only memory storage device 1140 is shown for remote computer 1138. Remote computer 1138 is logically connected to computer 1102 via network interface 1142, and then connected via communication connection 1144. Network interface 1142 encompasses wired or wireless communication networks, such as local area networks (LANs) and wide area networks (WANs), as well as cellular networks. LAN technologies include fiber distributed data interface (FDDI), copper distributed data interface (CDDI), Ethernet, token ring, and the like. WAN technologies include, but are not limited to, point-to-point links, circuit-switched networks such as integrated services digital networks (ISDN) and their variants, packet-switched networks, and digital subscriber lines (DSL).

[0098] The communication connection 1144 refers to the hardware / software used to connect the network interface 1142 to the bus 1108. Although the communication connection 1144 is shown internal to the computer 1102 for clarity of illustration, the communication connection can also be external to the computer 1102. For exemplary purposes only, the hardware / software required to connect to the network interface 1142 includes internal and external technology, such as modems, including conventional telephone-grade modems, cable modems, and DSL modems, ISDN adapters, as well as wired and wireless Ethernet cards, hubs, and routers.

[0099] Although the subject matter has been described above in the general context of computer-executable instructions of a computer program product running on one and / or multiple computers, it will be appreciated by those skilled in the art that the present disclosure may also be implemented or may be combined with other program modules. Generally speaking, program modules include routines, programs, components, data structures, etc. that perform specific tasks and / or implement specific abstract data types. In addition, it will be appreciated by those skilled in the art that other computer system configurations may be used to practice the computer-implemented methods of the present invention, including single-processor or multi-processor computer systems, small computing devices, mainframe computers, and computers, handheld computing devices (e.g., PDAs, phones), microprocessor-based or programmable consumer or industrial electronic devices, etc. The illustrated aspects may also be practiced in a distributed computing environment, in which tasks are performed by remote processing devices linked by a communication network. However, some (if not all) aspects of the present disclosure may be practiced on stand-alone computers. In a distributed computing environment, program modules may be located in local and remote memory storage devices.

[0100] As used in this application, the terms "component", "system", "platform", "interface", etc. may refer to and / or may include computer-related entities or entities related to operating machines having one or more specific functionalities. The entities disclosed herein may be hardware, a combination of hardware and software, software, or software in execution. For example, a component may be, but is not limited to, a program, a processor, an object, an executable file, an execution thread, a program, and / or a computer running on a processor. By way of illustration, both an application running on a server and a server may be components. One or more components may reside within a program and / or execution thread, and a component may be located on a single computer and / or distributed between two or more computers. As another example, the corresponding component may be executed based on various computer-readable media having various data structures stored thereon. Components may communicate via local and / or remote processes, such as based on signals having one or more data packets (e.g., data from a component that interacts with another component in a local system, a distributed system, and / or a network (such as the Internet with other systems) via signals). As another example, a component may be a device having specific functionality provided by mechanical parts operated by electrical or electronic circuitry, which is operated by a software or firmware application executed by a processor. In such cases, the processor may be internal or external to the device and may execute at least a portion of the software or firmware application. As yet another example, a component may be a device that provides specific functionality through electronic components rather than mechanical parts, where the electronic components may include a processor or other means for executing the software or firmware that at least partially imparts the functionality to the electronic components. In one aspect, the component may emulate the electronic component, for example, via a virtual machine within a cloud computing system.

[0101] In addition, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless otherwise specified or clear from the context, "X employs A or B" is intended to mean any natural inclusive permutation. That is, if X employs A; X employs B; or X employs both A and B, then "X employs A or B" is satisfied in any of the foregoing cases. In addition, unless otherwise specified or clear from the context to be directed to a singular form, the articles "a" and "an" used in this specification and the drawings should generally be understood to mean "one or more". As used herein, the terms "example" and / or "exemplary" are used to mean serving as an example, instance, or illustration, and are intended to be non-limiting. For the avoidance of doubt, the subject matter disclosed herein is not limited to such examples. In addition, any aspect or design described herein as "example" and / or "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects or designs, nor is it intended to exclude equivalent exemplary structures and techniques known to those of ordinary skill in the art.

[0102] As used in this specification, the term "processor" may refer to substantially any computational processing unit or device, including but not limited to a single-core processor; a single processor with software multithreading capability; a multi-core processor; a multi-core processor with software multithreading capability; a multi-core processor with hardware multithreading technology; a parallel platform; and a parallel platform with distributed shared memory. Additionally, a processor may refer to an integrated circuit, an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a field-programmable gate array (FPGA), a programmable logic controller (PLC), a complex programmable logic device (CPLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. Furthermore, a processor may utilize nanoscale architectures (such as, but not limited to, molecular and quantum dot-based transistors, switches, and gates) to optimize space usage or enhance the performance of user equipment. A processor may also be implemented as a combination of computational processing units. Throughout this disclosure, terms such as "repository," "storage," "data repository," "data storage," "data storage," "database," and substantially any other information storage component related to the operation and functionality of a component are used to refer to a "memory component," an entity embodied in "memory," or a component that includes memory. It should be understood that the memory and / or memory components described herein may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. By way of example and not limitation, non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable ROM (EEPROM), flash memory, or non-volatile random access memory (RAM) (e.g., ferroelectric RAM (FeRAM)). For example, volatile memory may include RAM that can act as external cache memory. By way of example and not limitation, RAM can be provided in a variety of forms, such as synchronous RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM), direct Rambus RAM (DRRAM), direct Rambus dynamic RAM (DRDRAM), and Rambus dynamic RAM (RDRAM). In addition, the disclosed memory components of the systems or computer-implemented methods herein are intended to include, but are not limited to, these and any other suitable types of memory.

[0103] What has been described above only includes examples of systems and computer-implemented methods. Of course, it is not possible to describe every conceivable combination of components or computer-implemented methods for the purposes of describing the present disclosure, but one of ordinary skill in the art will recognize that many other combinations and permutations of the present disclosure are possible. In addition, to the extent that the terms "including," "having," "having," and the like are used in the specific embodiments, claims, appendices, and drawings, such terms are intended to be inclusive in a manner similar to the term "including," as interpreted when "including" is used as a transitional word in the claims. Descriptions of various embodiments have been given for illustrative purposes, but these descriptions are not intended to be exhaustive or limited to the disclosed embodiments. Many modifications and variations will be apparent to one of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terms used herein are selected to best illustrate the principles of the embodiments, to be superior to practical applications or technical improvements of technologies found on the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method comprising: determining, by an apparatus comprising a processor, a two-dimensional (2D) spin echo sequence adapted for acquiring signal data associated with a slice of an anatomical region of a subject via a magnetic resonance imaging (MRI) system, wherein determining the 2D spin echo sequence comprises determining the 2D spin echo sequence according to a combination of a variable rate selective excitation (VERSE) protocol and a flow compensation along-slice protocol; Controlling, by the device, the MRI system to acquire the signal data using the 2D spin echo sequence; as well as An image of the slice is reconstructed by the device from the signal data.

2. The method of claim 1 , wherein based on determining the 2D spin echo sequence according to a combination, the image comprises a defined image quality and a specific absorption rate (SAR) of the acquisition is reduced relative to another SAR of a similar acquisition using a similar 2D spin echo sequence defined according to the along-slice flow compensation protocol but without the VERSE protocol. 3 . The method of claim 2 , wherein the defined image quality comprises an absence of flow artifacts or an amount of flow artifacts that is less than a defined amount.

4. The method according to claim 1, wherein The determination includes: defining, by the device, a first slice selection gradient waveform of the 2D spin echo sequence according to the VERSE protocol; and A second slice selection gradient waveform of the 2D spin echo sequence is defined by the apparatus according to the along-slice flow compensation protocol and based on the first slice selection gradient waveform.

5. The method according to claim 4, wherein Defining the first slice selection gradient waveform is further based on a scaling factor of a peak amplitude of a radio frequency pulse of a radio frequency pulse sequence used to define the 2D spin echo sequence.

6. The method of claim 5, wherein the first slice selection gradient waveforms each comprise a non-rectangular geometry, and wherein defining the second slice selection gradient waveform comprises: generating, by the device, a modeled version of the first slice selection gradient waveform having a rectangular geometry; determining, by the device, parameters associated with the first slice selection gradient waveform based on the modeled version; and The second slice selection gradient waveform is determined by the device based on the parameters.

7. The method according to claim 6, wherein: Determining the parameters includes determining a geometric area defined by the rectangular geometric shape of the modeled version, and determining the parameters based on the geometric area.

8. The method of claim 6, wherein the second slice selection gradient waveform comprises a slice rephasing gradient waveform.

9. The method of claim 6 , wherein the first slice selection gradient waveform comprises a gradient waveform temporally aligned with an initial excitation pulse of the radio frequency pulses and another gradient waveform temporally aligned with an initial refocusing pulse of the radio frequency pulses, and wherein the second slice selection gradient waveform is positioned between the first slice selection gradient waveforms.

10. The method of claim 1, wherein the 2D spin echo sequence comprises a turbo spin echo sequence.

11. A magnetic resonance imaging (MRI) system, comprising: at least one memory storing computer-executable components; as well as at least one processor that executes the computer-executable components stored in the at least one memory, wherein the computer-executable components include: a configuration component that determines a two-dimensional (2D) spin echo sequence, the 2D spin echo sequence being adapted to acquire signal data associated with a slice of an anatomical region of a subject via the MRI system, wherein the configuration component determines the 2D spin echo sequence according to a combination of a variable rate selective excitation (VERSE) protocol and an along-slice flow compensation protocol; a control component configured to control the MRI system to acquire the signal data using the 2D spin echo sequence; and A reconstruction component generates an image of the slice from the signal data.

12. The MRI system according to claim 11, wherein: Based on the configuration component determining the 2D spin echo sequence according to the combination, the image comprises a defined image quality and a specific absorption rate (SAR) of the acquisition is reduced relative to another SAR of a similar acquisition using a similar 2D spin echo sequence defined according to the along-slice flow compensation protocol without the VERSE protocol. 13 . The MRI system of claim 12 , wherein the defined image quality comprises an absence of flow artifacts or an amount of flow artifacts less than a defined amount.

14. The MRI system of claim 12 , wherein the configuration component defines a first slice selection gradient waveform of the 2D spin echo sequence according to the VERSE protocol, and further defines a second slice selection gradient waveform of the 2D spin echo sequence according to the along-slice flow compensation protocol and based on the first slice selection gradient waveform.

15. The MRI system according to claim 14, wherein: The configuration component defines the first slice selection gradient waveform based on a scaling factor of a peak amplitude of a radio frequency pulse of a radio frequency pulse sequence defining the 2D spin echo sequence.

16. The MRI system of claim 15, wherein the first slice selection gradient waveforms each comprise a non-rectangular geometry, and wherein the configuration component: generating a modeled version of the first slice selection gradient waveform having a rectangular geometry; determining parameters associated with the first slice selection gradient waveform based on the modeled version; and The second slice selection gradient waveform is determined based on the parameters. 17 . The MRI system of claim 16 , wherein the configuration component determines a geometric region defined by a rectangular geometric shape of the modeled version and determines the parameters based on the geometric region.

18. The MRI system of claim 16, wherein the second slice selection gradient waveform comprises a slice rephasing gradient waveform.

19. The MRI system of claim 16 , wherein the first slice selection gradient waveform comprises a gradient waveform temporally aligned with an initial excitation pulse of the radio frequency pulse and another gradient waveform temporally aligned with an initial refocusing pulse of the radio frequency pulse, and wherein the second slice selection gradient waveform is positioned between the first slice selection gradient waveforms.

20. A non-transitory machine-readable storage medium comprising executable instructions that, when executed by a processor, facilitate performance of operations comprising: determining a two-dimensional (2D) spin echo sequence adapted for acquiring signal data associated with a slice of an anatomical region of a subject via a magnetic resonance imaging (MRI) system, wherein determining the 2D spin echo sequence comprises determining the 2D spin echo sequence according to a combination of a variable rate selective excitation (VERSE) protocol and an along-slice flow compensation protocol; Controlling the acquisition of the signal data by the MRI system using the 2D spin echo sequence; and An image of the slice is generated based on the signal data.

Images