Improved Isotropic 3D FSE Methods for Imaging the Knee

 

Conventional MR imaging of the knee utilizes two-dimensional fast spin-echo (FSE) acquisitions that
require imaging at anisotropic resolutions and gaps between excitation slices. These highly anisotropic
methods introduce the risk of partial volume artifacts and prevent reformatting of image data in
different planes. Three-dimensional volumetric acquisitions at isotropic resolutions overcome these
problems, and may increase detection accuracy of pathology in joints imperceptible using 2D
methods. A newly developed 3D FSE sequence with extended echo train (3D-FSE-Cube) is currently
under investigation for use in diagnostic joint evaluation at 3 T. However, optimal pulse sequence
parameters for producing the highest quality images have yet to be determined. To ascertain these
values for a particular joint, 10 healthy subjects will receive knee MRIs at 3 T. The imaging parameters
repetition time (TR), receiver bandwidth, echo train length and parallel imaging factor will be
systematically altered for each subject while maintaining a constant scan time of 5 minutes and
isotropic spatial resolution of 0.6 mm. Qualitative measures for blurring and detail and quantitative
measures for signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) for different tissues will be
calculated. Parameter combinations maximizing SNR, CNR, and detail while minimizing blurring will
be considered optimal. The optimized 3D acquisition can then be further evaluated with respect to
traditional 2D FSE sequences, pre-optimized 3D-FSE-Cube sequences or arthroscopy for detection
sensitivity of joint pathology.

Charles Li, BS
Radiology Lucas Center for MR Spectroscopy and Imaging Stanford University

Charles is enrolled at the University of California, San Diego
School of Medicine

 

 

RSNA
Research Medical Student Grant

http://www.rsna.org/Foundation/upload/2009-Grants-and-Awards-Booklet_Final-2.pdf