Abnormal computed tomography brain scans in children with acute lymphoblastic leukemia: serial long-term follow-up.

In a previous study we reported the occurrence of computed tomographic (CT) brain-scan abnormalities in a group of asymptomatic children with acute lymphoblastic leukemia (ALL) who had received prophylactic cranial irradiation and maintenance intrathecal chemotherapy. One or more of four types of CT-scan abnormalities were observed: ventricular dilatation (VD), subarachnoid space dilatation (SAD), areas of parenchymal decreased attenuation coefficient (DAC), and intracerebral calcifications (CALs). To study the natural history of these findings, serial CT scans were obtained on 24 of the original 32 patients who were available for long-term follow-up. CT scanning was performed for a minimum of seven years from the initiation of CNS preventive therapy. Review of the CT scans showed that VD (n = 5) and SAD (n = 7) were stable over the time of follow-up. DAC, originally observed in two patients, was no longer present on follow-up scans. In contrast, five patients developed CALS from five to seven years after initiation of CNS preventive therapy. All occurred in children who were less than 8 years of age at the time of diagnosis (P less than .01). These data indicate that CALs may develop many years after the cessation of CNS preventive therapy and suggest that long-term CT-scan follow-up should be considered in children who have received CNS preventive therapy.