US-12625216-B2 - Magnetic resonance imaging techniques integrating variable rate selective excitation (VERSE) and flow compensation along slice

Abstract

Magnetic resonance imaging techniques integrating variable rate selective excitation (VERSE) and flow compensation along slice are described. According to an example, a method comprises determining, by a device comprising a processer, a two-dimensional (2D) spin echo sequence applicable for acquiring, via a MRI system, signal data associated with a slice of an anatomical region of a subject, wherein determining the 2D spin echo sequence comprises determining the 2D spin echo sequence in accordance with a combination of a VERSE protocol and a flow compensation along slice protocol. The method further comprises controlling, by the device, acquisition of the signal data by the MRI system using the 2D spin echo sequence, and reconstructing, by the device, an image of the slice from the signal data.

Inventors

• Anand Venkatachari

Assignees

• GE Precision Healthcare LLC

Dates

Publication Date

20260512

Application Date

20240320

Claims (20)

1. 1 . A method, comprising: determining, by a device comprising a processer and based on a combination of a variable rate selective excitation (VERSE) protocol and a flow compensation along slice protocol, a two-dimensional (2D) spin echo sequence applicable for acquiring, via a magnetic resonance imaging (MRI) system, signal data associated with a slice of an anatomical region of a subject, wherein the determining comprises: defining, by the device, first slice selection gradient waveforms of the 2D spin echo sequence in accordance with the VERSE protocol; and defining, by the device, a second slice selection gradient waveform of the 2D spin echo sequence in accordance with the flow compensation along slice protocol and based on the first slice selection gradient waveforms; controlling, by the device, acquisition of the signal data by the MRI system using the 2D spin echo sequence; and reconstructing, by the device, an image of the slice from the signal data.
2. 2 . The method of claim 1 , wherein based on determining the 2D spin echo sequence in accordance with 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 in accordance with the flow compensation along slice protocol and without the VERSE protocol.
3. 3 . The method of claim 2 , wherein the defined image quality comprises absence of flow artifacts or an amount of the flow artifacts being less than a defined amount.
4. 4 . The method of claim 1 , wherein the defining the first slice selection gradient waveforms is further based on a scaling factor used to define peak amplitudes of radio frequency pulses of a radio frequency pulse sequence of the 2D spin echo sequence.
5. 5 . The method of claim 4 , wherein the first slice selection gradient waveforms respectively comprise non-rectangular geometries, and wherein defining the second slice selection gradient waveform comprises: generating, by the device, modeled versions of the first slice selection gradient waveforms having rectangular geometries; determining, by the device, parameters associated with the first slice selection gradient waveforms based on the modeled versions; and determining, by the device, the second slice selection gradient waveform based on the parameters.
6. 6 . The method of claim 5 , wherein determining the parameters comprises determining geometrical areas defined by rectangular geometries of the modeled versions and determining the parameters based on the geometrical areas.
7. 7 . The method of claim 5 , wherein the second slice selection gradient waveform comprises a slice rephaser gradient waveform.
8. 8 . The method of claim 5 , wherein the first slice selection gradient waveforms comprise a gradient waveform aligned in time with an initial excitation pulse of the radio frequency pulses and another gradient waveform aligned in time 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.
9. 9 . The method of claim 1 , wherein the 2D spin echo sequence comprises a fast spin echo sequence.
10. 10 . A magnetic resonance imaging (MRI) system, comprising: at least one memory that stores computer-executable components; and at least one processor that executes the computer-executable components stored in the at least one memory, wherein the computer-executable components comprise: a configuration component that determines a two-dimensional (2D) spin echo sequence applicable for acquiring, via the MRI system, signal data associated with a slice of an anatomical region of a subject, wherein the configuration component determines the 2D spin echo sequence in accordance with a combination of a variable rate selective excitation (VERSE) protocol and a flow compensation along slice protocol, and wherein the configuration component defines first slice selection gradient waveforms of the 2D spin echo sequence in accordance with the VERSE protocol, and further defines a second slice selection gradient waveform of the 2D spin echo sequence in accordance with the flow compensation along slice protocol and based on the first slice selection gradient waveforms; a control component that controls 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.
11. 11 . The MRI system of claim 10 , wherein based on the configuration component determining the 2D spin echo sequence in accordance with 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 in accordance with the flow compensation along slice protocol and without the VERSE protocol.
12. 12 . The MRI system of claim 11 , wherein the defined image quality comprises absence of flow artifacts or an amount of the flow artifacts being less than a defined amount.
13. 13 . The MRI system of claim 11 , wherein the configuration component defines the first slice selection gradient waveforms based on a scaling factor used to define peak amplitudes of radio frequency pulses of a radio frequency pulse sequence of the 2D spin echo sequence.
14. 14 . The MRI system of claim 13 , wherein the first slice selection gradient waveforms respectively comprise non-rectangular geometries, and wherein the configuration component: generates modeled versions of the first slice selection gradient waveforms having rectangular geometries; determines parameters associated with the first slice selection gradient waveforms based on the modeled versions; and determines the second slice selection gradient waveform based on the parameters.
15. 15 . The MRI system of claim 14 , wherein the configuration component determines geometrical areas defined by rectangular geometries of the modeled versions and determines the parameters based on the geometrical areas.
16. 16 . The MRI system of claim 14 , wherein the second slice selection gradient waveform comprises a slice rephaser gradient waveform.
17. 17 . The MRI system of claim 14 , wherein the first slice selection gradient waveforms comprise a gradient waveform aligned in time with an initial excitation pulse of the radio frequency pulses and another gradient waveform aligned in time 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.
18. 18 . 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 applicable for acquiring, via a magnetic resonance imaging (MRI) system, signal data associated with a slice of an anatomical region of a subject, wherein determining the 2D spin echo sequence comprises: defining first slice selection gradient waveforms of the 2D spin echo sequence in accordance with a variable rate selective excitation (VERSE) protocol, and defining a second slice selection gradient waveform of the 2D spin echo sequence in accordance with a flow compensation along slice protocol and based on the first slice selection gradient waveforms; controlling acquisition of the signal data by the MRI system using the 2D spin echo sequence; and generating an image of the slice from the signal data.
19. 19 . The non-transitory machine-readable storage medium of claim 18 , wherein the defining the first slice selection gradient waveforms is further based on a scaling factor used to define peak amplitudes of radio frequency pulses of a radio frequency pulse sequence of the 2D spin echo sequence.
20. 20 . The non-transitory machine-readable storage medium of claim 19 , wherein the first slice selection gradient waveforms respectively comprise non-rectangular geometries, and wherein defining the second slice selection gradient waveform comprises: generating modeled versions of the first slice selection gradient waveforms having rectangular geometries; determining parameters associated with the first slice selection gradient waveforms based on the modeled versions; and determining the second slice selection gradient waveform based on the parameters.

Description

TECHNICAL FIELD This application relates to magnetic resonance imaging (MRI) and more particularly to MRI techniques integrating variable rate selective excitation (VERSE) and flow compensation along slice. BACKGROUND The specific absorption rate (SAR) is a measure of the rate at which energy is absorbed by the body when exposed to radiofrequency (RF) electromagnetic fields during a magnetic resonance imaging (MRI) scan. SAR is typically measured in units of watts per kilogram (W/kg). During an MRI scan, the RF pulses used to excite the protons in the body can cause heating of the tissues. SAR quantifies the amount of energy absorbed by the body per unit mass over time. It is an important safety consideration in MRI to ensure that the amount of energy absorbed does not exceed safe limits to prevent tissue heating and potential adverse effects. While MRI is generally considered a safe imaging modality, excessive tissue heating can cause burns, nerve stimulation, and other adverse effects. 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 the acquired images caused by flowing substances within the body, such as blood or cerebrospinal fluid. When imaging moving tissues or fluids, such as blood vessels or the cerebrospinal fluid, the motion can lead to undesirable artifacts in the MRI images. These flow artifacts can distort the anatomy being imaged and potentially lead to misinterpretation of the results. Flow compensation along slice in MRI refers to the application of flow compensation techniques to minimize or eliminate flow artifacts caused by motion perpendicular to the imaging plane, typically 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 a conventional MRI scanner). During the acquisition of multiple slices, there can be motion or flow of substances perpendicular to the slice direction, which can lead to phase errors and flow artifacts in the acquired images. To compensate for this motion and minimize its effects, flow compensation techniques along the slice direction 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 gradient pulses in the slice selection direction, it is possible to null or minimize the effects of motion-induced phase shifts along the slice direction. Using flow compensation along slice direction is of critical importance to reduce flow artifacts in 2D MRI scans involving multiple slices to cover the anatomical region of interest. Unfortunately, existing spin echo sequences used for multi-slice imaging can be very SAR intensive. Thus, techniques for reducing the SAR of multi-slice 2D MRI scans integrating flow compensation along slice are desired. SUMMARY The following presents a summary to provide a basic understanding of one or more embodiments of the invention. This summary is not intended to identify key or critical elements or delineate any scope of the different embodiments or any scope of the claims. Its sole purpose is to present concepts in a simplified form as a prelude to the more detailed description that is presented later. In one or more embodiments, systems, computer-implemented methods, apparatus and/or computer program products are described that provide MRI techniques integrating variable rate selective excitation (VERSE) and flow compensation along slice. According to an embodiment, an MRI system is provided that comprises at least one memory that stores computer-executable components, and at least one processor that executes the computer-executable components stored in the at least one memory. The computer-executable components comprise a configuration component that determines a 2D spin echo sequence applicable for acquiring, via the MRI system, signal data associated with a slice of an anatomical region of a subject, wherein the configuration component determines the 2D spin echo in accordance with a combination of a VERSE protocol and a flow compensation along slice protocol. The computer-executable components further comprise a control component that controls 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. To this end, based determining the 2D spin echo sequence in accordance with the combination, the image comprises a defined image quality and a SAR of the acquisition is reduced relative to another SAR of a similar acquisition using a similar 2D spin echo sequence defined in accordance with the flow compensation along slice protocol and without the VERSE protocol. In this regard, the defined image quality comprise