A peculiar brain scan pattern in necrotizing leukoencephalopathy after treatment for CNS-leukaemia

Two patients with CNS-leukaemia who developed a leukoencephalopathy after cranial irradiation and methotrexate administration are described. Conventional brain scanning with 99m TC-pertechnetate showed a peculiar pattern which suggested the presence of radio-activity within enlarged ventricles, but were later interpreted as accumulation in the periventricular white matter. The brainscan pattern correlated well with the neuropathological findings in the case where autopsy was performed. This brain scan pattern is for unknown reasons only rarely mentioned in literature. It seems a useful tool in diagnostic procedures in similar patients.