Selective MR imaging of segmented anatomy

• US 20080103383A1
• Filed: 10/23/2007
• Published: 05/01/2008
• Est. Priority Date: 10/23/2006
• Status: Active Grant

• Current Assignee: The General Hospital Corporation (Mass General Brigham, Inc.)
• Original Assignee: The General Hospital Corporation (Mass General Brigham, Inc.)
• Inventors: Wald, Lawrence, van der Kouwe, Andre, Fischl, Bruce
• Granted Patent: US 8,831,703 B2
• Time in Patent Office: Days
• US Class Current: 600/410
• CPC Class Codes: A61B 5/0037 Performing a preliminary scan, e.g. a prescan for identifying a region of interest
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/70 Means for positioning the patient in relation to the detecting, measuring or recording means
• CPC Class Codes: G01R 33/3415 comprising arrays of sub-coils , i.e. phased-array coils with flexible receiver channels
• CPC Class Codes: G01R 33/543 Control of the operation of the MR system, e.g. setting of acquisition parameters prior to or during MR data acquisition, dynamic shimming, use of one or more scout images for scan plane prescription G01R33/546 takes precedence
• CPC Class Codes: G01R 33/56 Image enhancement or correction, e.g. subtraction or averaging techniques , e.g. improvement of signal-to-noise ratio and resolution
• CPC Class Codes: G01R 33/5608 Data processing and visualization specially adapted for MR, e.g. for feature analysis and pattern recognition on the basis of measured MR data, segmentation of measured MR data, edge contour detection on the basis of measured MR data, for enhancing measured MR data in terms of signal-to-noise ratio by means of noise filtering or apodization, for enhancing measured MR data in terms of resolution by means for deblurring, windowing, zero filling, or generation of gray-scaled images, colour-coded images or images displaying vectors instead of pixels image data processing or generation, in general G06T

Abstract

A system and method for performing an MRI or MRS scan that is optimized for a particular target structure. A prescan is conducted during a first session in which an image that is optimized for segmentation is acquired along with an alignment scout image or a 2D or 3D navigator signal. The segmentation process is employed to locate and define the target structure. During a second session the alignment scout image or navigator signal is reacquired and the information is used to determine the position transformation needed to align images from the two sessions. The position transformation information and the segmentation information are then employed to tailor a prescribed pulse sequence to examine the target structure.

Claims

1. A method for imaging a desired structure in a subject with a magnetic resonance imaging (MRI) system, the steps comprising:

a) acquiring an image with the MRI system during a first session that depicts the desired structure;

b) segmenting the acquired image to identify a position and boundary of the desired structure;

c) prescribing a pulse sequence using data produced in step b); and

d) acquiring an image of the desired structure using the MRI system and the pulse sequence prescribed in step c).

2. The method of claim 1 wherein step c) includes:

c)i) displaying segmentation data produced in step b);

c)ii) selecting, from the displayed segmentation data, the desired structure to be imaged; and

c)iii) setting scan parameters in a selected pulse sequence based on the selected desired structure.

3. The method of claim 2 wherein the scan parameters set in step c)iii) includes a waveform of an RF pulse produced by each of a plurality of RF coils such that the resulting RF magnetic field is positioned and shaped according to the position and shape of the selected desired structure.

4. The method of claim 1 further comprising the step of:

e) between steps a) and b), acquiring alignment data with the MRI system during the first session that indicates a position of the subject during step a); and

f) after step b), acquiring alignment data with the MRI system during a second session; and

g) after step f) and before step d), aligning the subject in the first and second sessions using the alignment data acquired therein.

5. The method of claim 4 further comprising removing the subject from the MRI system between steps e) and f).

6. The method of claim 4 wherein step g) includes:

g)i) relating the left-posterior-superior (LPS) of the MRI system through a matrix (M<sub>CRS→

LPS</sub>^seg) determined from a prescription of the MRI system given by an automated segmentation program, such that;

v_LPS^seg=M<sub>CRS→

LPS</sub>^segv_CRS^seg.

7. The method of claim 6 wherein step g) further includes:

g)ii) relating the LPS coordinates of the MRI system to anatomical LPS coordinates using an AutoAlign matrix given by;

v_AA/LPS=(M_AA^seg)<sup>−

1</sup>v_LPS^seg.

8. The method of claim 7 wherein step g) further includes:

g)iii) using an AutoAlign matrix M_AA determined using an AutoAlign procedure to relate the LPS coordinate of the MRI system for a given session to anatomical LPS coordinates, where;

v_LPS=M_AAv_AA/LPS.

9. The method of claim 1 wherein step b) further includes selecting an automated segmentation method including at least one of a centroid segmentation method, a bounding box segmentation method, a bounded box segmentation method, and a minimum projection segmentation method.

10. The method of claim 1 further comprising step e) repeating steps c) and d) to acquire multiple images with different prescribed pulse sequences selected for different desired structures in the subject.

11. A method for imaging a desired structure in a subject with a magnetic resonance imaging (MRI) system, the steps comprising:

a) performing a first data acquisition session with the MRI system comprising;

a)i) acquiring a first set imaging data from a portion of the subject including the desired structure;

a)ii) acquiring alignment data that indicates a position of the subject during the first data acquisition session;

b) reconstructing a first image from the first set of imaging data acquired during step a);

c) segmenting the first image to identify a position and boundary of the desired structure;

d) performing a second data acquisition session with the MRI system comprising;

d)i) acquiring alignment data that indicates a position of the subject during the second data acquisition session;

d)ii) positioning the subject in the position of the subject during the first data acquisition session using the alignment data acquired during the first imaging session and the alignment data acquired during the second imaging session;

d)iii) prescribing a pulse sequence based on the position and boundary of the desired structure identified in step c) to target the desired structure;

d)iv) acquiring a second set of imaging data from a portion of the patient including the desired structure using the MRI system and the pulse sequence prescribed in step d)iii); and

e) reconstructing an image of the desired structure from at least the second set of imaging data.

12. The method of claim 11 further comprising removing the subject from the MRI system between steps a) and d).

13. The method of claim 11 wherein step c) further includes selecting an automated segmentation method including at least one of a centroid segmentation method, a bounding box segmentation method, a bounded box segmentation method, and a minimum projection segmentation method.

14. The method of claim 11 further comprising step f) repeating steps d)iii) and d)iv) to acquire multiple imaging data sets with different prescribed pulse sequences selected for different desired structures in the subject.

15. The method of claim 11 wherein step d)iii) includes displaying the position and boundary of the desired structure identified in step c), selecting, from the display, the desired structure to be imaged, and setting scan parameters in a selected pulse sequence based on the selected desired structure.

16. The method of claim 11 wherein step a)ii) includes acquiring at least one of alignment scout image and a navigator signal.

17. The method of claim 11 wherein step d)i) includes acquiring at least one of alignment scout image and a navigator signal.