CLINICOPATHOLOGICAL CORRELATIONS IN SYRINGOMYELIA USING AXIAL MAGNETIC-RESONANCE-IMAGING

AXIAL MAGNETIC RESONANCE (MR) images of non-neoplastic spinal cord cav ities were reviewed in 115 patients with otherwise complete neurologic al and neuroradiological findings. The variations in axial morphology revealed three distinct cavitary patterns. These patterns were as foll ows: 1) symmetrically enlarged central cavities (28 patients); 2) cent ral cavities that expanded paracentrally in one or more focal areas (3 6 patients); and 3) eccentric cavities that were off-center, frequentl y irregular, and sometimes associated with myelomalacia (51 patients). The radiological patterns of spinal cord cavitation correlated well w ith recently reported histopathological findings that distinguish simp le dilations of the central canal, dilations of the central canal that dissect paracentrally, and primary cavitations of the spinal cord par enchyma (extracanalicular syringes). Like histologically confirmed cen tral canal syringes, MR-defined central cavities were associated with pathogenic factors that affect the dynamics of the cerebrospinal fluid , including hindbrain malformations, hydrocephalus, and extramedullary obstructive lesions. Eccentric cavities resembled extracanalicular sy ringes and occurred typically with disorders that damage spinal cord t issue (e.g., trauma, infarction, meningitis/arachnoiditis, spondylosis /disc herniation, radiation necrosis, and transverse myelitis). Analys is of clinical findings at the time of MR imaging established the foll owing correlations, 1) Symmetrically enlarged central cavities were as ymptomatic or produced nonspecific neurological signs. 2) Central cavi ties that expanded paracentrally were associated with segmental signs referable to the paracentral component. 3) Eccentric cavities produced various combinations of long tract and segmental signs that could usu ally be related to the level, side, and specific quadrant of spinal co rd cavitation. We conclude that axial plane MR imaging provides consid erable information about the cross-sectional morphology of syrinx cavi ties, and this information correlates well with the clinical and patho logical features of these lesions.