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

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


  • 1 Thesleff S, Ward MR. Studies on the mechanism of fibrillation potentials in denervated muscle. J Physiol 1975; 244(2): 313–323. Crossref, MedlineGoogle Scholar
  • 2 Bryan WW, Reisch JS, McDonald G, Herbelin LL, Barohn RJ, Fleckenstein JL. Magnetic resonance imaging of muscle in amyotrophic lateral sclerosis. Neurology 1998; 51(1): 110–113. Crossref, MedlineGoogle Scholar
  • 3 Kikuchi Y, Nakamura T, Takayama S, Horiuchi Y, Toyama Y. MR imaging in the diagnosis of denervated and reinnervated skeletal muscles: experimental study in rats. Radiology 2003; 229(3): 861–867. LinkGoogle Scholar
  • 4 Bendszus M, Koltzenburg M. Visualization of denervated muscle by gadolinium-enhanced MRI. Neurology 2001; 57(9): 1709–1711. Crossref, MedlineGoogle Scholar
  • 5 May DA, Disler DG, Jones EA, Balkissoon AA, Manaster BJ. Abnormal signal intensity in skeletal muscle at MR imaging: patterns, pearls, and pitfalls. RadioGraphics 2000; 20(Spec Issue): S295–S315. LinkGoogle Scholar
  • 6 Grant GA, Britz GW, Goodkin R, Jarvik JG, Maravilla K, Kliot M. The utility of magnetic resonance imaging in evaluating peripheral nerve disorders. Muscle Nerve 2002; 25(3): 314–331. Crossref, MedlineGoogle Scholar
  • 7 Polak JF, Jolesz FA, Adams DF. Magnetic resonance imaging of skeletal muscle: prolongation of T1 and T2 subsequent to denervation. Invest Radiol 1988; 23(5): 365–369. Crossref, MedlineGoogle Scholar
  • 8 Sano S, Nagano T, Imai T, Gotoh M, Kojima T, Nishijima H. An experimental study on entrapment neuropathy by sciatic nerve compression in the rat. J Jpn Soc Surg Hand 1985; 2: 565–568. Google Scholar
  • 9 Bridge PM, Ball DJ, Mackinnon SE, et al. Nerve crush injuries: a model for axonotmesis. Exp Neurol 1994; 127(2): 284–290. Crossref, MedlineGoogle Scholar
  • 10 Mulkern RV, Wong ST, Jakab P, Bleier AR, Sandor T, Jolesz FA. CPMG imaging sequences for high field in vivo transverse relaxation studies. Magn Reson Med 1990; 16(1): 67–79. Crossref, MedlineGoogle Scholar
  • 11 George LT, Myckatyn TM, Jensen JN, Hunter DA, Mackinnon SE. Functional recovery and histomorphometric assessment following tibial nerve injury in the mouse. J Reconstr Microsurg 2003; 19(1): 41–48. Crossref, MedlineGoogle Scholar
  • 12 Shabas D, Gerard G, Rossi D. Magnetic resonance imaging examination of denervated muscle. Comput Radiol 1987; 11(1): 9–13. Crossref, MedlineGoogle Scholar
  • 13 Fleckenstein JL, Watumull D, Conner KE, et al. Denervated human skeletal muscle: MR imaging evaluation. Radiology 1993; 187(1): 213–218. LinkGoogle Scholar
  • 14 Uetani M, Hayashi K, Matsunaga N, Imamura K, Ito N. Denervated skeletal muscle: MR imaging—work in progress. Radiology 1993; 189(2): 511–515. LinkGoogle Scholar
  • 15 West GA, Haynor DR, Goodkin R, et al. Magnetic resonance imaging signal changes in denervated muscles after peripheral nerve injury. Neurosurgery 1994; 35(6): 1077–1086. Crossref, MedlineGoogle Scholar
  • 16 Henkelman RM, Stanisz GJ, Kim JK, Bronskill MJ. Anisotropy of NMR properties of tissues. Magn Reson Med 1994; 32(5): 592–601. Crossref, MedlineGoogle Scholar
  • 17 Pierpaoli C, Basser PJ. Toward a quantitative assessment of diffusion anisotropy. Magn Reson Med 1996; 36(6): 893–906. Crossref, MedlineGoogle Scholar
  • 18 Basser PJ, Mattiello J, LeBihan D. MR diffusion tensor spectroscopy and imaging. Biophys J 1994; 66(1): 259–267. Crossref, MedlineGoogle Scholar
  • 19 Hajnal JV, Doran M, Hall AS, et al. MR imaging of anisotropically restricted diffusion of water in the nervous system: technical, anatomic and pathologic considerations. J Comput Assist Tomogr 1991; 15(1): 1–18. Crossref, MedlineGoogle Scholar
  • 20 Pierpaoli C, Jezzard P, Basser PJ, Barnett A, Di Chigro G. Diffusion tensor imaging of the human brain. Radiology 1996; 201(3): 637–648. LinkGoogle Scholar

Article History

Published in print: 2008