Multiple sclerosis: magnetic resonance imaging, evoked responses, and spinal fluid electrophoresis.

Magnetic resonance images (MRI), evoked responses (ER), and CSF findings were compared in 39 patients with possible, probable, or definite MS. MRI disclosed multiple lesions (72%) more often than ERs (55%) in the total group of patients. In possible MS, MRI showed multiple lesions in 71%, and ER abnormalities were found in 41%. MRI is the preferred test for patients with suspected MS, but ERs are useful when MRI is normal and in the evaluation of optic nerve or spinal cord lesions.