The initial diagnosis of multiple sclerosis: clinical impact of magnetic resonance imaging.

Thirty patients in whom the initial diagnosis of multiple sclerosis was clinically entertained underwent cranial magnetic resonance imaging (MRI) in close temporal relationship to cranial x-ray computed tomography (CT), electrodiagnostic studies (visual evoked responses, brainstem auditory evoked responses, and somatosensory evoked responses), and cerebrospinal fluid analyses (oligoclonal bands, myelin basic protein, and IgG/albumin ratio). In 26 of the 30 patients, MRI demonstrated lesions consistent with multiple sclerosis that corresponded, at least in part, with the clinically expected neuroanatomical lesion distribution. Two of the 4 patients with normal MRI had normal electrodiagnostic studies and cerebrospinal fluid analyses, and the other 2 had a single abnormal or equivocal electrodiagnostic study. All 26 patients with abnormal MRI had at least one other abnormal laboratory test. CT revealed only the largest lesions, and in the patients with abnormal CT, MRI demonstrated even more lesions. MRI, in this limited series, proved to be a strong tool in the initial diagnosis of multiple sclerosis; it may prove to be the single best test, with a sensitivity exceeding that of electrodiagnostic studies and cerebrospinal fluid analysis.