Bone marrow magnetic resonance studies in childhood leukemia. Evaluation of osteonecrosis

In 25 patients under treatment or during follow‐up for acute lymphoblastic leukemia magnetic resonance imaging (MRI) of both knees was compared to history and physical examination to detect osteonecrosis. Results of MRI were classified as: O, normal bone marrow (BM); 1, diffuse decrease in signal intensity; 2, circumscript lesions. Patients clinically suspected of osteonecrosis had a statistically significant increased incidence of Type 2 lesions. Three patients with a BM relapse also showed Type 2 lesions. Circumscript lesions of the epiphyses were seen exclusively in the four patients with clinical suspicion of osteonecrosis during BM remission and this may be a MR finding strongly indicative of osteonecrosis. Patients with Type 2 lesions during BM remission had received systemic chemotherapy for a statistically significant longer period than the other patients. Using MRI findings we suspect that at least four patients suffered osteonecrosis due to chemotherapy. MRI is a promising means of detecting this disorder.