Method and apparatus for separating chemical species in magnetic resonance imaging

Patent metadata

Field	Value
Publication number	US-2016187447-A1
Application number	US-201414584501-A
Country	US
Kind code	A1
Filing date	Dec 29, 2014
Priority date	Dec 29, 2014
Publication date	Jun 30, 2016
Grant date	—

Abstract

A method that includes obtaining an MRI gradient echo train of at least three echo data sets at differing phase angles; producing a plurality of phase error maps among the at least three echo data sets; and imaging at least three distinct chemical species based on the plurality of phase error maps.

First claim

What is claimed is:

1 . A method comprising:
obtaining an MRI gradient echo train of at least three echo data sets of signals at differing phase angles; producing a plurality of phase error maps among the at least three echo data sets; and imaging at least three distinct chemical species based on the plurality of phase error maps.

2 . The method of claim 1 wherein the MRI gradient echo train is obtained by a fast spin echo triple echo Dixon sequence.

3 . The method of claim 1 wherein the MRI gradient echo train is obtained in a single scan using a bipolar readout.

4 . The method of claim 1 wherein the MRI gradient echo train is obtained by dynamic contrast enhanced sequence.

5 . The method of claim 1 wherein the MRI gradient echo train is obtained by parallel imaging.

6 . The method of claim 1 wherein separate images of water, fat, and silicone are obtained without use of inversion or suppression pulses.

7 . The method of claim 6 wherein imaging water, fat, and silicone includes developing a first fat image from a first phase error map and developing a second fat image from a second phase error map, and modifying at least some of the at least three echo data sets according to the first and second fat images.

8 . A method comprising:
obtaining an MRI gradient echo train of at least three echo data sets, wherein the third echo data set is consecutive between the first and second echo data sets; producing an outer phase error map by performing a 2-point Dixon separation on the non-consecutive first and second echo data sets of the MRI gradient echo train; modifying the at least three echo data sets of the MRI gradient echo train according to the outer phase error map; producing a first phase error map by performing a 2-point Dixon separation on the modified first echo data set and the modified third echo data set; producing a second phase error map by performing a 2-point Dixon separation on the modified second echo data set and the modified third echo data set; and imaging fat and water, excluding in vivo silicone, based on the first and second phase error maps.

9 . The method of claim 8 wherein the MRI gradient echo train is obtained by a fast spin echo triple echo Dixon sequence.

10 . The method of claim 8 wherein the MRI gradient echo train is obtained in a single scan using a bipolar readout.

11 . The method of claim 8 wherein the MRI gradient echo train is obtained in multiple scans.

12 . The method of claim 8 wherein separate images of water, fat, and silicone are obtained without use of inversion or suppression pulses.

13 . The method of claim 8 wherein modifying the at least three echo data sets includes developing a silicone image from the outer phase error map and subtracting the silicone image from the echo data sets.

14 . An apparatus comprising:
an MRI system control that is configured to obtain an MRI gradient echo train of at least three echo data sets, wherein the third echo data set is consecutive between the first and second echo data sets; and an image processor module that is configured to produce a plurality of phase error maps among the at least three echo data sets, and to image at least two distinct chemical species based on the plurality of phase error maps.

15 . The apparatus of claim 14 wherein the image processor module is configured to produce an outer phase error map that is obtained by performing a 2-point Dixon separation on non-consecutive out-of-phase first and second echo data sets of the MRI gradient echo train; to modify echo data sets of the MRI gradient echo train according to the outer phase error map; to produce a first phase error map by performing a 2-point Dixon separation on the modified first echo data set and the modified third echo data set;
to produce a second phase error map by performing a 2-point Dixon separation on the modified second echo data set and the modified third echo data set; and to image water and fat, excluding in vivo silicone, based on the first and second phase error maps.

16 . The apparatus of claim 14 wherein the MRI gradient echo train is obtained by a fast spin echo triple echo Dixon sequence.

17 . The apparatus of claim 14 wherein the MRI gradient echo train is obtained in a single scan using a bipolar readout.

18 . The apparatus of claim 14 wherein the MRI gradient echo train is obtained in multiple scans.

19 . The apparatus of claim 14 wherein separate images of water, fat, and silicone are obtained without use of inversion or suppression pulses.

20 . An apparatus comprising:
an MRI system control that is configured to obtain an MRI gradient echo train of at least three echo data sets; and an image processor module that is configured to produce a first phase error map by performing a first 2-point Dixon separation on consecutive first and second echo data sets of the MRI gradient echo train; produce a second phase error map by performing a second 2-point Dixon separation on consecutive second and third echo data sets of the MRI gradient echo train; modify the non-consecutive first and third echo data sets according to the first and second phase error maps; produce a third phase error map by performing a third 2-point Dixon separation on the modified first and third echo data sets; and image three chemical species based on the three phase error maps.

21 . The method of claim 19 wherein the MRI gradient echo train is obtained in a single scan using a bipolar readout and a fast spin echo triple echo Dixon sequence.

22 . The method of claim 19 wherein the MRI gradient echo train is obtained in multiple scans.

23 . A method comprising:
obtaining an MRI gradient echo train of at least three echo data sets; producing a first phase error map by performing a first 2-point Dixon separation on consecutive first and second echo data sets of the MRI gradient echo train, wherein the first echo data set is out-of-phase and the second echo data set is in-phase; producing a second phase error map by performing a second 2-point Dixon separation on consecutive second and third echo data sets of the MRI gradient echo train, wherein the third echo data set is out-of-phase; modifying the non-consecutive out-of-phase first and third echo data sets according to the first and second phase error maps; producing a third phase error map by performing a third 2-point Dixon separation on the modified out-of-phase first and third echo data sets; and imaging three chemical species based on the three phase error maps.

Assignees

• Gen Electric
• Univ Texas

Inventors

• Hwang Ken-Pin
• Slavens Zachary William
• Bayram Ersin
• Wang Kang
• Litwiller Daniel
• Ma Jingfei

Classifications

• G01R33/4828 Primary

  Resolving the MR signals of different chemical species, e.g. water-fat imaging · CPC title

• G01R33/5615 Primary

  Echo train techniques involving acquiring plural, differently encoded, echo signals after one RF excitation, e.g. using gradient refocusing in echo planar imaging [EPI], RF refocusing in rapid acquisition with relaxation enhancement [RARE] or using both RF and gradient refocusing in gradient and spin echo imaging [GRASE] · CPC title

• G01R33/5616

  using gradient refocusing, e.g. EPI · CPC title

• G01R33/485

  based on chemical shift information {[CSI] or spectroscopic imaging, e.g. to acquire the spatial distributions of metabolites} · CPC title