Quantitative ultrasound detects bone changes following bone marrow transplantation in pediatric subjects with hematological diseases: a longitudinal study

Bone marrow transplantation (BMT) is associated with bone morbidity. We investigated bone status with quantitative ultrasound (QUS) in pediatric patients with hematological diseases prior to and up to 3 yr following BMT. Phalangeal QUS measures for amplitude- dependent speed of sound (Ad-SoS) and bone transmission time (BTT) were obtained in 40 hematological patients (25 with malignant, 15 with non-malignant disease; 9.7+/-4.9 yr) before BMT and 6, 12, 24, and 36 months after BMT. Bone parameters were expressed as Z-scores based on age-sex-matched normal controls. Mean Ad-SoS and BTT Z-scores were normal before BMT and reduced at 36 months (analysis of variance: p=0.0542 and p=0.0233). Ad-SoS and BTT Z-scores remained relatively stable in the first 6 months after BMT and then progressively decreased reaching a plateau at 12-36 months. In non-malignant patients, BTT Z-score decreased at 6-12 months (p=0.029) and subsequently increased, while in malignant patients BTT Z-score showed a decrease at 12-24 months. Pre-pubertal subjects displayed a drop of BTT Z-Score values at both 12 (p=0.023) and 36 months after BMT (p=0.049), while BTT Z-score remained relatively unchanged in pubertal subjects. Early impairment of BTT Z-score was found in patients who suffered acute graft versus host disease (GVHD) compared to patients without this clinical condition; BTT Z-score was lower at 36 months (p=0.045). Longitudinal assessment by QUS of pediatric BMT survivors evidenced that bone status is mildly affected up to 36 months after BMT, mainly in malignant patients, in pre-pubertal subjects at BMT and in patients who suffered acute GVHD.