MR imaging of multiple sclerosis: comparison with clinical and CT examinations in 74 patients.

Magnetic resonance (MR) imaging, the latest test for evaluation of patients with multiple sclerosis (MS), was assessed against clinical evidence in 74 patients with definite or probable MS. MR imaging was positive in 55 (85%) of 65 patients with definite MS but in only one (11%) of nine patients with probable MS. The examination is most likely to be positive when the patient is classified clinically as having definite MS; when the disease is active and not in remission; and if the constellation of symptoms indicates a multiplicity of regions with neurologic dysfunction. The examination was most sensitive for detecting lesions in the cerebral hemispheres, the posterior fossa, and the cervical spinal cord, in that order; it did not detect any lesions in the optic nerves. The paraclinical tests and MR imaging were of equal sensitivity in detecting MS lesions, but the latter method was more specific in localization. Cerebrospinal fluid evaluation was slightly less sensitive than the other two tests. There was no correlation between MR imaging and these examinations. The authors conclude that MR imaging is more sensitive than computed tomography (CT), which was positive in 25% of 59 patients with definite MS; it is always positive when CT is positive; and it probably can replace CT in the diagnosis and follow-up of patients with MS.