# US 5,347,216 A · Fast NMR image acquisition with spectrally selective inversion pulse

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- Number: US 5,347,216 A
- Document ID: US5347216A
- Status: Granted
- Kind: A
- Application number: 07/902,634
- Filed: 1992-06-23
- Granted: 1994-09-13
- Earliest claimed: 1992-06-23
- Assignees: General Electric Company
- Inventors: Thomas K. Foo
- Web page: https://patentgrep.com/patent/US5347216A

## CPC

- G01R 33/4828: {Resolving the MR signals of different chemical species, e.g. water-fat imaging}
- G01R 33/561: by reduction of the scanning time, i.e. fast acquiring systems, e.g. using echo-planar pulse sequences
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)

## Abstract

An NMR system performs a 3DFT scan using a set of steady-state free precession (SSFP) pulse sequences. A contrast preparation pulse sequence precedes each series of SSFP pulse sequences employed to acquire one plane through the three-dimensional space, and it includes a spectrally selective RF inversion pulse tuned to fat or water. The sequence is repeated without any magnetization recovery delays until all the planes have been acquired.

## Claims

### Claim 1

In an NMR system, a method for conducting a scan comprised of a set of steady-state free precession pulse sequences in which a magnetic field gradient is stepped through a corresponding set of values to acquire NMR data from which an image is reconstructed, the steps comprising:
a) performing a contrast preparation pulse sequence which includes producing a spectrally selective RF inversion pulse which is tuned to the Larmor frequency of a selected spin species to be suppressed in the reconstructed image;
b) performing a SSFP pulse sequence series in which a subset of said set of steady-state free precession pulse sequences are performed to acquire a portion of the NMR data; and
c) repeating steps a) and b) until all steady-state free precession pulse sequences in said set have been performed without any significant recovery period therebetween.

### Claim 2 (depends on 1)

The method as recited in claim 1 in which the selected spin species is fat.

### Claim 3 (depends on 1)

The method as recited in claim 1 in which the selected spin species is water.

### Claim 4 (depends on 1)

The method as recited in claim 1 in which the NMR data is a 3DFT data set, in which each steady-state free precession pulse sequence includes a second magnetic field gradient, and in which step c) includes incrementing the value of the second magnetic field gradient before repeating steps a) and b).