Diffusion weighted preparatory sequence for magnetic resonance imaging pulse sequence

• US 7,804,299 B2
• Filed: 05/04/2007
• Issued: 09/28/2010
• Est. Priority Date: 05/04/2007
• Status: Active Grant

• Current Assignee: General Electric Company, Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Original Assignee: Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Inventors: Brittain, Jean H., Busse, Reed, Reeder, Scott B.
• Primary Examiner(s): Shrivastav; Brij B
• Application Number:
  US11/800,374
• Publication Number:
  US 20080275329A1
• Time in Patent Office: 1,243 Days
• Field of Search: 324300-322, 600407-435
• US Class Current: 324/309
• CPC Class Codes: G01R 33/56341 Diffusion imaging

Abstract

A preparatory pulse sequence is applied prior to an imaging pulse sequence during a diffusion-weighted MRI scan. The preparatory pulse sequence diffusion weights the longitudinal magnetization using a gradient waveform that is first moment nulled to reduce image artifacts caused by patient motion.

Claims

1. A method for producing a diffusion-weighted image with a magnetic resonance imaging (MRI) system, the steps comprising:

a) performing a preparation pulse sequence with the MRI system that diffusion weights longitudinal magnetization in a subject, the preparation pulse sequence including;

a)i) applying a radio frequency (RF) excitation pulse to produce transverse spin magnetization;

a)ii) applying a first moment nulled diffusion weighting gradient waveform to diffusion weight the transverse spin magnetization;

a)iii) applying an RF excitation pulse to produce diffusion-weighted longitudinal spin magnetization from the diffusion weighted transverse magnetization; and

a)iv) applying an RF refocusing pulse such that the diffusion weighted transverse magnetization is refocused when the RF excitation pulse is produced in step a)iii);

b) performing an imaging pulse sequence following step a);

c) repeating steps a) and b) as necessary to acquire a set of data from which an image can be reconstructed; and

d) reconstructing a diffusion-weighted image from the acquired set of data.

2. The method as recited in claim 1 in which the diffusion-weighted gradient waveform is also second moment nulled.

3. The method as recited in claim 1 in which a pair of RF refocusing pulses are applied during step a)iv).