MRI follow-up study of aseptic osteonecrosis (AON) in children treated with chemotherapy for malignant diseases

The aim of the study was to evaluate by MRI the course of aseptic osteonecrosis (AON) after chemotherapy in children with different malignancies. Retrospective analysis of 72 MRI studies in 20 children (age: 3.2-18.4 years) presenting with AON after chemotherapy. 8 children were treated exclusively with relief of weightbearing structures, whereas 12 children were additionally treated with hyperbaric oxygen therapy (HBO). Within a range of 3-76 months each patient received 1-6 follow-up exams. The acquired series included multi planar spin-echo as well as fatt-suppressed inversion recovery sequences. The MRI examinations were evaluated by a point-score system (1-6) by two radiologists. AON was most commonly seen in the pedal bones (26.4%), in the hip (23.6%), and in the knee joints (19.4%). Initial findings revealed an average score of 3.1 points. Based upon these initial findings, subsequent analyses show a statistically significant (p < 0.05) score increase of 0.6 score-points. For the observed intervals a: < 6 months, b: 6-12 months, and c: > 12 months the mean scores were: a: 3.3, b: 3.7, and c: 4.5 points. During the observed time period 5 patients were surgically treated in the affected bone areas. The majority of chemotherapy associated AON which initially present with advanced findings showed in MRI a progression with frequent destruction of the joint surface over their further course. More discrete forms of AON, especially osteoedema, can be positively influenced by conservative therapy.