Vertebral trabecular attenuation serial changes on chest CT after autologous hematopoietic stem cell transplantation

OBJECTIVE: Transplant-associated bone disease and fragility fractures are recognized complications after hematopoietic stem cell transplantation (HSCT). We aimed to evaluate early and longitudinal changes in vertebral trabecular attenuation on routine chest CT in patients undergoing autologous HSCT. MATERIALS AND METHODS: In this retrospective single-centre study, 98 adult patients who underwent autologous HSCT and had both pre-transplant and early post-transplant (≤ 30 days) non-contrast chest CT were included. Vertebral trabecular attenuation was measured in Hounsfield units (HU) at T10-T12 and vertebral body height was measured in millimeters. Longitudinal changes were additionally evaluated in patients with available late follow-up CT (> 30 days) (n = 61). RESULTS: Vertebral trabecular attenuation decreased significantly from pre-transplant to early post-transplant CT (163.0 ± 57.0 HU vs. 132.7 ± 53.9 HU; p < 0.001). In patients with late follow-up imaging, attenuation remained lower than baseline (157.3 ± 58.7 HU vs. 125.3 ± 56.1 HU; p < 0.001). The proportion of attenuation values within the osteoporosis range (≤ 110 HU) increased from 20.4% at baseline to 39.8% early after transplantation. Among patients with late follow-up imaging, this proportion increased from 27.4% to 45.2% early after transplantation and remained elevated at 48.4% at late follow-up. Vertebral body height remained unchanged during the early post-transplant period but decreased significantly at late follow-up. CONCLUSION: Vertebral trabecular attenuation on routine chest CT declines within the first month after autologous HSCT and remains reduced on follow-up imaging. Opportunistic CT-based assessment may enable early identification of skeletal vulnerability.