Purpose:
Chronic thromboembolic pulmonary hypertension (CTEPH) is a life-threatening but curable form of pulmonary hypertension. Early diagnosis is crucial for effective management and improved outcomes. Computed tomography pulmonary angiography (CTPA), characterised by high sensitivity and specificity, is integral to diagnosing CTEPH by identifying thrombi and associated pulmonary and mediastinal abnormalities. However, radiological features often overlap with other diseases, and their detection depends on radiologist expertise. This study aims to assess the frequency of characteristic radiological features in CTEPH, compare their prevalence with chronic thromboembolic disease (CTED), pulmonary arterial hypertension (PAH), and acute pulmonary embolism (APE), and evaluate their diagnostic predictive value.

Material and methods:
This retrospective study analysed 115 patients divided into CTEPH (n = 35), CTED (n = 20), PAH (n = 24), and APE (n = 36) groups, matched by age and sex. CTPA scans were reviewed for signs of chronic embolism, pulmonary hypertension, and right heart overload. Sensitivity, specificity, accuracy, and predictive values were assessed using ROC analysis, expressed as the area under the curve (AUC).

Results:
CTEPH patients exhibited vessel narrowing, intimal irregularities, bands, and webs in all cases (100%), with the highest diagnostic value at the segmental level (AUC = 0.906). Mosaic perfusion and variability in vessel size demonstrated moderate predictive value (AUC = 0.740 and AUC = 0.788, respectively).

Conclusions:
CTPA is essential for differentiating CTEPH from other pulmonary vascular conditions. While no single feature achieves 100% predictive value, a comprehensive approach integrating vascular, parenchymal, and cardiac findings is critical for accurate diagnosis.