MR Imaging of Carpal Tunnel Syndrome : The Usefulness of MRI in Treatment Decisions

Lee, Kyu-Yong; Lee, Young Joo; Kim, Seung Hyun; Song, Hyoung Gon; Kim, Juhan

Ann Clin Neurophysiol > 2002 ;4(2) > Article

Ann Clin Neurophysiol. 2002; 4(2): 114-118.

Kyu-Yong Lee, Young Joo Lee, Seung Hyun Kim, Hyoung Gon Song, and Juhan Kim

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

ABSTRACT

Backgrounds : Carpal tunnel syndrome(CTS) is a common condition that is usually diagnosed by electrophysiologic studies. However, CTS provide limited information to determine the causes of CTS and to choose the treatment method. We evaluated diagnostic sensitivity of MR imaging and treatment decisions by MR imaging in electrodiagnosed CTS. Methods : 14 patients (26 wrists) with electrodiagnosed CTS were studied using MR imaging. In 26 wrists for which axial T1 & T2 weighted images were obtained at 1.5T with a decided wrist coil. Previously described MR imaging of CTS such as increased median nerve signal, flattening of median nerve, reticular bowing, tenosynovitis and space occupying lesions were retrospectively evaluated. Degree of improvement was evaluated by global symptom score(GSS). The GSS rated symptoms from 0 (no symptoms) to 10 (severe0 in each of five categories; pain, numbness, paresthesia, weakness/clumsiness, and nocturnal awaking. Subjects' GSS was recorded at baseline, 2 weeks, 1 month,6 months after treatment. We decided to medical treatment that showed mainly inflammatory sign such as increased median nerve signal, tenosinvitis and to surgical treatment such as space occupying lesion, high canal pressure sign. Results : MR imaging showed that increased median nerve signal were in 29 wrists(77%), flattening of median nerve were in 6 wrists (23%), reticular bowing were in 3 wrists (12%), tenosyovitis were in 8 wrists (32%), decreased canal size in 2 wrists (7.6%), space occupying lesion were in 1 wrists (4%). A good outcome was revealed in 21 wrists by medical treatment that showed mainly increased median nerve signal, tenosynovitis. The mean GSS were 27.7 at baseline 11.2 at 2 weeks, 11.0 at 6 month in medical treatment group. Another 5 wrists had surgical treatment shown by ganglion and high canal pressure sign such as median nerve flattening, reticular bowing, decreased canal size : 3 wrists had good prognosis, but 2 wrists (one patient) had no significant improvement due to small carpal tunnel size. Conclusions : Our results are in agreement with most previously described MR imaging signs of CTS. MR imaging plays an important role in several cases and especially in the assessment of failure of surgical treatment. Knowledge of MR findings may permit more rational choice of treatment.

Key words: Carpal Tunnel syndrome, MR imaging, Treatment methods