Mitsuharu Tamakawa MD, Presenter: Nothing to Disclose

Hidenari Akiba MD, PhD, Abstract Co-Author: Nothing to Disclose

Hideki Hyodoh MD, Abstract Co-Author: Nothing to Disclose

Kazusa Hyodoh MD, Abstract Co-Author: Nothing to Disclose

Naoya Yama MD, Abstract Co-Author: Nothing to Disclose

Yuriko Kawaai, Abstract Co-Author: Nothing to Disclose

Taishi Satoh MD, Abstract Co-Author: Nothing to Disclose

Masato Hareyama MD, Abstract Co-Author: Nothing to Disclose

00030490-DMT et al, Abstract Co-Author: Nothing to Disclose

To verify whether a diffusion weighted (DW) image can diagnose carpal tunnel syndrome earlier than a T2 weighted image.

DW-MR imaging was performed in 8 normal volunteers and 18 patients with classical carpal tunnel syndrome, 16 months of an average disease span, prospectively. The following sequences were applied: a diffusion-weighted SE-EPI image sequence (repetition time msec/ echo time msec, 5000/60; b value, 500, 600, and 700; 3.5mm section thickness, 0.3mm gap, 10 signals acquired, 128x102 matrix, 10-cm field of view, and acquisition time of 3.5 minutes) and T2-weighted two-dimensional turbo SE sequence (3500/120, 3.5mm section thickness, 0.3mm gap, 2 signal acquired, 256x256 matrix, 10-cm field of view, and acquisition time of 2.5 minutes). T2-weighted and DW- MR sequence were performed in transverse plane. Normal volunteer were performed in DW-MR sequence for change b value form 500 sec/mm2 to 700 sec/mm2 in order to determine optimal b value. A normal signal of median nerve on DW-MR imaging was emitted in x- and y-direction of MPG pulse additions and disappeared in z-direction of MPG pulse addition. DW-MR images of disturbed axonal flows of median nerver show high intensity in all direction of MPG pulse additions.

A median nerve signal in z-direction of MPG pulse addition disappeared over 500sec/mm2 of b-value in all volunteers. Signal to noise ratio of DW-MR image in 500sec/m2 was higher than that of other b-values. It was showed high intensity of median nerve on DW-MR images in 16 of 18 patients and abnormal high intensity or flattening or proximal nerve swelling on T2-weighted MR images in 11 of 18 patients. DW-MR imagings of remaining two patients showed no signal of all direction of MPG pulse additions and median nerve severe flattening on T2-weighted sequence.

DW-MR imaging may be able to detect abnormal findings to the early stage of carpal tunnel syndrome in which normal median nerve appearance was showed on a T2-weighted MR imaging.

A DW-MR iamges of a median nerve will offer the objective evidence which supports the symptoms of a patient with early carpal tunnel syndrome.

Tamakawa, M, Akiba, H, Hyodoh, H, Hyodoh, K, Yama, N, Kawaai, Y, Satoh, T, Hareyama, M, et al, 0, Early Stage Diagnosis of Carpal Tunnel Syndrome Using Diffusion-weighted MR Imaging.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8015997.html