CT-derived vascular parameters and bone mineral density in adults with cystic fibrosis

Cystic fibrosis (CF) is a multisystem disorder in which reduced bone mineral density (BMD) is a common and clinically significant complication. While dual-energy X-ray absorptiometry (DEXA) is the standard diagnostic method, imaging-derived parameters from routinely performed thoracic computed tomography (CT) may provide additional insight into systemic disease burden. This study aimed to investigate the association between CT-derived vascular metrics and BMD in adults with CF.

This retrospective observational study included adult CF patients who underwent dual-energy X-ray absorptiometry (DEXA) and thoracic CT between 2017 and 2023 at a tertiary referral center. Clinical variables, pulmonary function, hospitalization history, inflammatory markers, and CT-derived vascular measurements including pulmonary artery (PA) diameter, ascending aortic (Ao) diameter, and PA/Ao ratio were analyzed. Patients were categorized according to World Health Organization osteopenia criteria and a low BMD subgroup (T-score < -1.5). Receiver operating characteristic (ROC) analyses and multivariate logistic regression were performed to identify factors associated with low BMD.

Seventy-four adult CF patients were included. Using the standard osteopenia threshold (T-score < -1.0), patients with low BMD had significantly lower FEV₁, lower body mass index, and higher CF-ABLE scores. In the low BMD subgroup (T-score < -1.5), patients were younger (p = 0.008), had smaller ascending aortic diameters (p = 0.005), higher PA/Ao ratios (p = 0.029), and more hospitalizations (p = 0.046). ROC analysis demonstrated moderate discriminatory performance for CT aortic diameter (AUC = 0.746) and age (AUC = 0.723). In multivariate analysis, younger age remained the only independent predictor of low BMD (OR 0.81, 95% CI 0.67-0.97, p = 0.025).

CT-derived vascular parameters were associated with low BMD in adults with CF, particularly in patients with more advanced bone loss. These findings suggest that vascular metrics may reflect more advanced systemic disease involvement rather than early osteopenia. However, given the cross-sectional design, causality cannot be inferred. Prospective longitudinal studies are needed to validate the predictive value of these imaging markers and clarify the relationship between vascular alterations and bone health.