Effects of chemotherapy and lipopolysaccharide (LPS) on osteocytes: Possible mechanisms for osteonecrosis (ON) during treatment for childhood acute lymphoblastic leukaemia (ALL)

Background: Avascular necrosis of the bone (AVN) is a devastating complication in pediatric patients with acute lymphoblastic leukemia (ALL), and articular surface involvement is associated with progressive joint damage. Total body MRI (TBMRI) is a new, non-invasive imaging modality which can identify multiple sites with AVN, with increased STIR signal with corresponding hypointense borders on the T-1 weighted imaging corresponding to AVN lesions. Objectives: To report TBMRI data on 10 patients with pediatric ALL with recent onset of bone pain. Methods: 10 patients (7F, 3M) diagnosed with ALL at median (range) age of 6.2 (3–18) years, and recently developing bone pain were examined with X-ray imaging of the symptomatic region and with TBMRI. TBMRI with coronal T1 and STIR of entire body, with axial T2 fat saturated imaging was performed on each patient at a median (range) of 9 (2–49) months after ALL diagnosis. Results: None of the initial X-ray images revealed abnormal findings. TBMRI showed in 9 of 10 children bone marrow lesions compatible with AVN. In addition to a symptomatic site, all patients had multiple additional lesions. In total, there were a median (range) of 14.5 (5–17)AVN lesions per patient,with amedian (range) of 4.5 (0– 6) lesions per patient at articular surfaces: knee joints (n=8patients); humerus (n=6 patients); femoral heads (n=1 patient); and ankles (n=4 patients). 8/9 patients with articular surface involvement had bilateral lesions. The size varied from small focal lesions to lesions measuring over 95% of the whole transverse diameter of the bone. None of the patients to date have required surgical intervention, but each patient is followed by repeat TBMRI every 6 months. Conclusion: 1. Total body MRI allows early diagnosis of symptomatic as well as clinically non-apparent avascular necrosis (AVN) in pediatric patients with leukemia. 2. TBMRI can be used in planning for medical or surgical therapies.