Identification of pulmonary hypertension with pulmonary vascular surface volume ratio by non-contrast CT

The diagnosis of pulmonary hypertension (PH) relies primarily on invasive right heart catheterization (RHC). Although imaging modalities, including echocardiography, computed tomography angiography (CTA) and computed tomography (CT), offer clinical utility, their effectiveness in early detection remains limited.

To clarify the relationship between group 1/2 PH and radiomic-morphological features of the pulmonary vasculature derived from non-contrast CT.

We retrospectively enrolled control patients and patients with group 1 PH (PAH) and group 2 PH (PH-LHD) from two centers. All participants underwent RHC and chest CT. We extracted the radiomic features from pulmonary arteries and veins, identifying key radiomics markers and further exploring their association with early pathological changes through animal experiments. Subsequently, we analyzed morphological characteristics from 95,197 vascular centerlines. Multivariable models were employed to evaluate their efficacy in identifying PH and discriminating PH-LHD in validation cohort.

The training cohort included 49 patients (20 controls, 13 with PAH, 16 with PH-LHD), and validation cohort included 30 patients. Among 212 radiomics features analysis, the pulmonary arterial surface volume ratio (SVR) correlated strongly with mean pulmonary artery pressure (mPAP) (r = -0.602, P < 0.001), while the venous SVR showed a strong correlation with pulmonary artery wedge pressure (PAWP) (r = -0.651, P < 0.001). In animal models, venous SVR demonstrated the ability to reflect early pulmonary venous remodeling in PH-LHD prior to hemodynamic changes. Morphologically, PH-LHD patients showed increased distal vessel tortuosity with reduced torsion and curvature (all P < 0.001). SVR and models combining morphological features demonstrated promising performance for identifying PH (AUC 0.895 (95%CI (0.731-1.000)) vs. 0.890 (95%CI (0.736-1.000)) and distinguishing PH-LHD (AUC 0.868 (95%CI (0.672-1.000) vs. 0.846 (95%CI 0.639-0.990)) in validation cohort.

CT-based radiomic-morphological analysis provides a basis for identifying PH and distinguishing its subtypes. Specifically, arterial SVR aids in PH detection, while venous SVR helps differentiate PH-LHD from PAH, together forming a clinically useful screening pathway. Preclinical evidence additionally links venous SVR to venous remodeling that may precede hemodynamic changes. These findings require validation in larger PH populations.