Abstract Introduction Chronic thromboembolic pulmonary hypertension (CTEPH) derives from recurrent pulmonary embolism, leading to intraluminal obstructions of pulmonary vessels. The detection or exclusion of CTEPH is essential for differential diagnosis of pulmonary hypertension (PH) and therapeutic decision making. The gold standard for the detection of CTEPH is ventilation/perfusion scintigraphy (V/Q scan). However, novel tools such as Dual-Layer Dual-Energy Computed Tomography Pulmonary Angiography (dlDECT), which enable perfusion analysis using Iodine Density Overlay (IDO) Mapping, are readily available. We aimed at comparing the diagnostic accuracy of dlDECT versus V/Q scan for CTEPH. Methods All patients receiving structured PH diagnostics and perfusion imaging (including both dlDECT and V/Q scan) at the PH centre of our university hospital between 05/2016 and 02/2024 were included. Gold standard for CTEPH diagnosis was the final expert consensus of the multi-disciplinary CTEPH team, taking into account clinical presentation, medical history, hemodynamics (right heart catheterization), cardiac (echocardiography) and lung perfusion imaging (dlDECT, V/Q scan, pulmonary angiography). The imaging modalities were retrospectively considered according to the initial expert reading. The diagnostic value was determined as sensitivity/specificity, positive (PPV)/negative predictive value (NPV), and overall diagnostic accuracy. Results A total of 471 patients (mean age 67 ± 13 years, 57% female) with structured PH diagnostics were enrolled, of whom 113 (24%) had a final diagnosis of CTEPH (mean age 64 ±15 years, 47% female). Among those, the mean pulmonary artery pressure at diagnosis was 43.5 ± 12.6 mmHg, pulmonary arterial wedge pressure was 11.9 ± 6.3 mmHg, cardiac index 2.3 ± 0.5 l/min/m2, and pulmonary vascular resistance 9.1 ± 5.7 Wood units. The results of V/Q Scan and dlDECT in the CTEPH and No CTEPH groups are shown in Table 1, and imaging findings related to PH are summarized in Table 2. The sensitivity and specificity for the detection of CTEPH were 94% and 93% for dlDECT, and 100% and 89% for V/Q scan, respectively. The PPV for dlDECT and V/Q scan was 80% and 73%, and the NPV was 98% and 100%, respectively. The overall diagnostic accuracy was 91% for V/Q scan and 93% for dlDECT. Conclusions Both dlDECT and V/Q scan are suitable methods for diagnosing CTEPH. The sensitivity of dlDECT is considerably higher than published data on conventional CT pulmonary angiography, indicating the additional value of perfusion imaging with dlDECT.
Kural et al. (2025) studied this question.