ASYMPTOMATIC SPINAL-CORD LESIONS IN CLINICALLY ISOLATED OPTIC-NERVE, BRAIN-STEM, AND SPINAL-CORD SYNDROMES SUGGESTIVE OF DEMYELINATION

Objectives-Conventional T2 weighted MRI studies have highlighted the f act that the presence of clinically silent brain lesions increases the risk of developing clinically definite multiple sclerosis after an is olated syndrome of the optic nerve, brain stem, or spinal cord. The ob jectives of the present study are: (1) to show whether or not these pa tients also have asymptomatic abnormalities of the spinal cord, and (2 ) to recruit a new cohort of such patients using high resolution MRI o f both brain and spinal cord. Methods-The brain was imaged in the axia l plane with 3 mm thick contiguous slices using a proton density and T 2 weighted fast spin echo (FSE) sequence; a T1 weighted sequence after the injection of gadolinium-DTPA; and a fast fluid attenuated inversi on recovery (fFLAIR) sequence. The spinal cord was imaged in the sagit tal plane with 3 mm thick slices using a T2 weighted FSE and a T1 weig hted gadolinium enhanced sequence. Results-Thirty three patients, mean age 31 (16-46) were recruited. There were 14 men and 19 women. Brain MRI was abnormal in 22 (67%); no patient was seen with abnormalities o n only one or other sequence. Six patients (18%) displayed one or more gadolinium enhancing lesions on brain MRI. In the spinal cord, nine ( 27%) patients displayed one or more clinically silent lesions on FSE. Two patients showed one and two gadolinium enhancing lesions in the sp inal cord respectively. Conclusion-This high incidence of spinal cord lesions emphasises that asymptomatic demyelinating lesions may also in volve clinically eloquent pathways. Follow up studies are required to determine their prognostic importance.