Opportunistic Quantitative Analysis of Bone Mineral Density and Vertebral Height in Cardiac Transplant Recipients Using Routine Chest CT Scans.

Background: Osteoporosis is a common complication in cardiac transplant recipients. While dual-energy X-ray absorptiometry (DEXA) is the standard method for assessing bone mineral density (BMD), it has limitations. This study aimed to evaluate the potential of using routine non-contrast chest CTs in cardiac transplant patients to assess BMD and vertebral body height.

Methods: 98 cardiac transplant patients who had undergone CTs before and after transplantation, along with DEXA scans, were included in this observational study. The CTs were used to measure vertebral bone density and height at thoracic vertebral levels. CT-based bone density before and after transplantation was compared and correlated with DEXA scan bone density.

Results: The findings revealed a significant decrease in vertebral bone density in the middle thoracic region (T5-T8) from 175 to 163 Hounsfield Units (HU) and in the lower thoracic region (T9-T12) from 163 to 146 HU after transplantation (P<.05). A strong correlation was observed between the bone density values derived from CTs and those from DEXA scans (P<.05). Furthermore, vertebral body height significantly changed at specific levels (T3, T6, T11, and T12) (P<.05). The anterior and middle portions of vertebral body showed a significant reduction in median height of 0.02 cm and 0.03 cm, respectively (P<.05), while changes in the posterior portion were not significant (P>.05).

Conclusion: Routine non-contrast chest CTs commonly performed for cardiac transplant patients, can effectively assess bone density, presenting a potential alternative to DEXA scans in this patient population.