American Journal of Neuroradiology 21:1793-1798 (11 2000)
© 2000 American Society of Neuroradiology
ARTICLE
MR Imaging of the Cauda Equina in Hereditary Motor Sensory Neuropathies: Correlations with Sural Nerve Biopsy
a From the Neuroradiology Unit (M.C.), Azienda Ospedaliera Careggi, Florence; and the Radiodiagnostic Section, Department of Clinical Physiopathology (S.S., V.D.) and Division of Neurology, Department of Neurological and Mental Sciences (G.M.), University of Florence, Florence, Italy.
b Address reprint request to M. Cellerini M.D., U.O. Neuroradiologia, Centro Traumatologico (CTO), Azienda Ospedaliera Careggi, Largo Palagi 1, 50134 Firenze, Italy.
BACKGROUND AND PURPOSE: Although spinal root abnormalities are known to occur, spinal MR examination is seldom performed in hereditary motor and sensory neuropathies (HMSN). The following work was undertaken to assess the MR imaging spectrum of lumbosacral spinal nerve root abnormalities and determine whether intradural nerve root involvement could be related to any biopsy feature.
METHODS: Ten consecutive patients (eight male, two female; age range, 28–65 yrs) with Charcot-Marie-Tooth (CMT) (type I = 5, type II = 2) and Déjèrine-Sottas disease (DSD) (n = 3) underwent a contrast-enhanced lumbosacral MR examination. Sural nerve biopsy was perfomed in all patients. Atypical clinical features were present in two patients. The MR scans of each patient were reviewed for possible causes of myeloradiculopathy, spinal nerve root and ganglia dimensions, signal change, and abnormal enhancement.
RESULTS: In the seven patients with CMT, abnormal MR findings were intradural nerve root hypertrophy (n = 2), signal abnormalities (n = 2), and enhancement (n = 3). Two of three patients with DSD had the abnormal MR finding of intradural nerve root enhancement. In both patients with atypical clinical features, MR imaging showed nerve root hypertrophy and enhancement. Both findings were related to an increased number of onion bulbs at sural nerve biopsy. Inflammatory infiltrates were not observed in any patients.
CONCLUSION: In patients with HMSN enhancement of intradural spinal nerve roots, whether or not associated with marked thickening, may be found on lumbosacral MR examinations. Spinal nerve root thickening may be responsible for atypical symptoms, and its visibility on MR images represents a useful adjunct to diagnosis. Lumbosacral spinal nerve root abnormalities were related to an extremely high number of onion bulbs (indicating active demyelination) at sural nerve biopsy. Nerve root enhancement does not seem to be related to inflammatory infiltrates.