Chronic subdural hematoma: reliability of radioisotope imaging versus computed tomography

25 surgically verified cases of chronic subdural hematoma (CSH) were examined retrospectively. All the patients had been investigated both with computed tomography (CT) and with radioisotope imaging (RI). RI supplied a correct diagnosis in all cases whilst CT yielded a doubtful diagnosis (generic signs of space-occupying lesion) in 5 cases and normal findings (false negative) in one. The clinical use of the two investigations is discussed. The study shows the reliability of RI in the diagnosis of CSH especially when CT determines the site but not the nature of the lesion (hematoma in the isodense phase).