Vascular Obstruction Scoring on Dual-energy CT, Cone-beam CT and Digital Subtraction Angiography: Correlation with Invasive Hemodynamics in Chronic Thromboembolic Pulmonary Hypertension

RATIONALE AND OBJECTIVES: To evaluate correlations between a standardized vascular obstruction score and invasive hemodynamic parameters in chronic thromboembolic pulmonary hypertension (CTEPH), using dual-energy CT (DECT), cone-beam CT (CBCT), and digital subtraction angiography (DSA). MATERIALS AND METHODS: In this retrospective single-center study, 109 patients with CTEPH underwent DECT, CBCT, and DSA within a 3-month interval. A standardized vascular obstruction score was applied independently to each modality. Linear regression models were constructed to assess associations with mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance (PVR), cardiac output (CO), and cardiac index (CI), quantified by adjusted R². Score distributions were compared using Friedman and Wilcoxon tests, and interobserver agreement was assessed with Cohen's κ. RESULTS: DSA demonstrated the highest degree of association with mPAP and PVR among the evaluated modalities (adjusted R² = 0.089 and 0.126), followed by DECT (0.075 and 0.098) and CBCT (0.050 and 0.062). DSA also correlated with CO and CI. Mean obstruction scores differed significantly across modalities (p < 0.001), with DECT yielding higher values than CBCT (p < 0.001) and DSA (p < 0.001). Interobserver agreement was highest for CBCT (κ = 0.76) and DECT (κ = 0.74), and lowest for DSA (κ = 0.57). None of the modalities correlated significantly with NYHA class or 6MWD. CONCLUSION: A unified morphologic vascular obstruction score applied across DECT, CBCT, and DSA demonstrates reproducible associations with invasive hemodynamic parameters in CTEPH. While not a replacement for right heart catheterization, it provides a standardized framework for multimodality assessment and may support methodological integration across imaging modalities. CRITICAL RELEVANCE STATEMENT: This study presents a systematic application of a unified vascular obstruction scoring system across dual-energy CT, cone-beam CT, and digital subtraction angiography in patients with chronic thromboembolic pulmonary hypertension. The results demonstrate significant correlations with invasive hemodynamic parameters, with dual-energy CT and cone-beam CT providing higher reproducibility than angiography. These findings support the use of a standardized scoring framework to enable consistent multimodality assessment, improve reproducibility in structured multimodality imaging assessment, and facilitate cross-institutional comparisons in chronic thromboembolic pulmonary hypertension.