SUPERFICIAL SIDEROSIS OF THE CENTRAL-NERVOUS-SYSTEM - MRI FINDINGS AND CLINICAL-SIGNIFICANCE

We reviewed a 7-year series of brain MRI examinations to determine the frequency and clinical significance of superficial siderosis of the c entral nervous system (SS). SS was defined by widespread bilateral sig nal loss at the surfaces of the cerebral or cerebellar hemispheres, th e brain stem and the spinal cord on T2-weighted images. Clinical data comprised a neurological examination of identified patients and a revi ew of their case notes. Among 8843 consecutive studies we identified 1 3 (0.15%) patients with MRI evidence of SS. Only 2 had symp toms or si gns characteristic of SS, such as cerebellar ataxia, hearing loss, mye lopathy and dementia. Haemosiderin deposition was most widespread in b oth symptomatic individuals. A definite cause for SS was detected in 9 patients (69%). None of them had a full clinical picture of SS. These data indicate SS per se to be much more frequent than may be assumed from the literature. It appears to become symptomatic only with extens ive amounts of widespread iron deposition which develop preferentially with cryptic or unidentified causes of bleeding.