Scott Brian Reeder, Presenter: Nothing to Disclose

Christopher Frederick Beaulieu MD, Abstract Co-Author: Nothing to Disclose

Jane W Johnson, Abstract Co-Author: Nothing to Disclose

Huanzhou Yu MS, Abstract Co-Author: Nothing to Disclose

Jean H Brittain PhD, Abstract Co-Author: Nothing to Disclose

Garry Evan Gold MD, Abstract Co-Author: Nothing to Disclose

Norbert Joseph Pelc ScD, Abstract Co-Author: Nothing to Disclose

Ann Shimakawa MS, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

To compare performance of fat suppression, image quality and SNR achieved with a Dixon water-fat separation method, STIR, and fat-saturation in combination with T1W and T2W fast spin-echo imaging of the brachial plexus

Both T1W post-contrast and T2W MRI of the brachial plexus are limited by the lack of reliable fat suppression due to complex air-tissue interfaces. STIR imaging provides uniform fat suppression, but at the cost of reduced SNR. We developed a novel multi-coil Dixon method to separate water and fat using fast spin-echo (FSE) imaging. Sagittal FSE T2-weighted images were acquired in 5 volunteers on a GE 1.5T scanner using a neurovascular coil. For T2W fat saturated (FS) imaging TR/TE=3850/45, NSA=3, scan time=3:59min. For Dixon T2W imaging, TR/TE=4325/45ms, NSA=1, scan time=4:33min. For T2W fast-STIR imaging, TR/TE=6675/45ms, NSA=2, scan time=4:34min.T1W Dixon FSE imaging used TR/TE=650/15, NSA=1, scan time=6:20min. T1W FS imaging used NSA=3, but identical parameters otherwise.Two radiologists scored images on a 4-point grading scale (0-3, 3=best) for both fat-suppression and overall image quality. SNR was measured in muscle, spinal cord, and CSF.

Image quality of T1W and T2W Dixon images was excellent as was fat suppression even in challenging areas near the lung apices.Fat-suppression score of T2W Dixon images (3.0) was statistically superior (p=0.04) to T2W FS imaging (0.6), but similar to STIR (3.0). Image quality for Dixon (3.0) was superior (p=0.03) to STIR (2.0) and FS (1.8). SNR for T2W Dixon imaging was 15-30% higher than FS (p=0.02), and 25-58% higher than STIR (p=0.02). Fat-suppression score of T1W Dixon images (3.0) was superior (p=0.04) to T1W FS imaging (0.6), as was image quality (3.0 vs 1.6,p=0.04). SNR for T1W Dixon imaging was similar to T1W FS in muscle. SNR in the proximal cord was 30% higher for T1W Dixon imaging, although this was not significant (p=0.25).

Both T1W and T2W Dixon imaging of the brachial plexus provide uniform water-fat separation and excellent image quality. T1W Dixon provides a potential new method for robust post-contrast imaging of the brachial plexus and similarly challenging body areas.

Reeder, S, Beaulieu, C, Johnson, J, Yu, H, Brittain, J, Gold, G, Pelc, N, Shimakawa, A, et al, , T1 and T2 Weighted Brachial Plexus Imaging with Fast Spin-Echo and “Dixon” Fat-Water Separation: Comparison with STIR and Fat Saturation.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4410352.html