HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) All Versions of this Article: 2472070403v1 247/2/409    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Yamabe, E. Articles by Toyama, Y. PubMed PubMed Citation Articles by Yamabe, E. Articles by Toyama, Y. Related Collections Related Article

Peripheral Nerve Injury: Diagnosis with MR Imaging of Denervated Skeletal Muscle—Experimental Study in Rats¹

¹ From the Departments of Orthopaedic Surgery (E.Y., T.N., Y.K., H.I., Y.T.) and Diagnostic Radiology (K.O.), School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. Received February 28, 2007; revision requested May 9; revision received July 17; accepted August 17; final version accepted October 8. Supported by the General Insurance Association of Japan. Address correspondence to T.N. (e-mail: tosiyasu{at}sc.itc.keio.ac.jp).

Purpose: To prospectively evaluate signal intensity change on T2-weighted magnetic resonance (MR) images and the time course of T2 values and T2 ratios after reinnervation in various nerve injury models in rats.

Materials and Methods: Institutional animal use and care committee approval was obtained. Thirty male rats made up four groups of rats with an injured left posterior tibial nerve (irreversible neurotmesis, reversible neurotmesis, severe axonotmesis, or moderate axonotmesis) and one control group. There were six rats in each group. Signal intensity changes were seen in the gastrocnemius muscle on the T2-weighted MR images. T2 values were also measured in vivo with the Carr-Purcell-Meiboom-Gill method. Gait function was assessed by calculating the print length factor (PLF). T2 ratios and PLFs on the injured side were compared with those on the unaffected side. Ratios of specific acquisition points within groups were compared by using repeated-measures analysis of variance. Comparisons across the five groups at each acquisition point were performed by using one-way analysis of variance with Scheffe post hoc testing. P < .05 indicated a significant difference.

Results: The more severe the nerve damage, the higher the signal intensity on T2-weighted MR images. There were significant differences in T2 ratios between the nerve injury groups and the control group (P < .05). Changes in T2 values and ratios depended on the degree of nerve injury. In the reversible neurotmesis group, T2 values and ratios began to decrease 28 days after surgery. In the severe and moderate axonotmesis groups, T2 values and ratios began to decrease 14 days after surgery. The starting point of functional recovery also depended on the degree of nerve injury.

Conclusion: The degree and prognosis of nerve injury can be evaluated by observing changes in signal intensity on T2-weighted images and the time course of T2 values and ratios.

© RSNA, 2008

Related Article

Can MR Imaging Be Used to Predict the Degree and Prognosis of Peripheral Nerve Injuries?

Christian W. A. Pfirrmann
Radiology 2008 247: 301-302. [Full Text] [PDF]