Changes in calcaneal trabecular bone structure after heart transplantation: An MR imaging study

PURPOSE: To use high-spatial-resolution magnetic resonance (MR) imaging to analyze the trabecular bone structure of the calcaneus in patients before a nd after heart transplantation and to compare this technique with bone mine ral density (BMD) measurement in predicting therapy-induced bone loss and v ertebral fracture status. MATERIALS AND METHODS: High-spatial-resolution 1.5-T MR imaging of the calc aneus was performed in 40 men 11-120 months after heart transplantation, in 11 men before heart transplantation, and in 10 age-matched male volunteers . Sagittal and transverse T1-weighted spin-echo images with a voxel size of 0.195 x 0.195 x 1.000 mm were obtained, and structure measurements analogo us to bone histomorphometric values were calculated. In addition, the BMD o f the lumbar spine was determined in the transplant recipients pre- and pos toperatively by using quantitative computed tomography, and vertebral fract ure status was assessed. RESULTS: Significant differences in structure and BMD measurements were fou nd between patients before and after heart transplantation (P <. 05). In 17 (42%) of 40 transplant recipients, vertebral fractures were found. Althoug h structure measurements were significantly different between patients with and those without fractures (P < .05), BMDs were not. Correlations between time after transplantation and some structure measurements were moderately significant (P <. 05), but such correlations with BMD measurements were no t. CONCLUSION: MR imaging-derived structure measurements in the calcaneus are useful for monitoring bone changes after heart transplantation and assessin g vertebral fracture status.