Correlation between cranial computed tomographic scans at diagnosis in children with acute lymphoblastic leukaemia and central nervous system relapse.

145 children with acute lymphoblastic leukaemia (ALL) were evaluated over a period of 3 years in a multicentre study in which serial cranial computed tomographic (CT) scans of the brain were done. All patients were symptom-free. CT scans were graded as normal, borderline (slight or moderate cerebral atrophy), or pathological (severe cerebral atrophy). 62% (90/145) of children had CT scan abnormalities at diagnosis. After a median follow-up of 24 months (range 6-36) 12 of 108 evaluable patients had central nervous system (CNS) relapses (6 isolated relapses and 6 combined with relapse at another site). All patients with CNS relapse had an abnormal CT scan at diagnosis (8 pathological and 4 borderline). No relapses were observed among the 42 patients with a normal cranial CT scan at diagnosis. A significantly higher proportion of severe cerebral atrophy, both following CNS prophylaxis and after the discontinuation of treatment, was found among patients with a borderline CT scan at diagnosis than among patients with a normal CT scan at diagnosis. Thus an abnormal cranial CT scan at diagnosis in children with ALL seems to have prognostic significance.