Etiological Classification and Computed Tomography Features of Pulmonary Artery Dissection

Objective: To characterize the etiological classification and computed tomography (CT) features of pulmonary artery dissection (PAD), and to evaluate the association between distinct imaging findings and mortality. Methods: The clinical data and CT imaging features of 37 patients with confirmed PAD diagnosed between July 2006 and December 2024 were retrospectively analyzed. Results: Among the 37 patients, six had pulmonary hypertension (PH)-associated PAD (mean age: 37.0±11.2 years), all of whom had main pulmonary artery dilation (mean diameter: 50.7±15.2 mm) and right ventricular wall thickening. The remaining 31 patients had aortic dissection (AD)-associated PAD (mean age: 58.1±11.3 years), comprising 30 Stanford Type A and one Type B; nine patients (29.0%) in this subgroup died. Within the AD-associated PAD group, the intimal tear was localized to the posterior wall of the ascending aorta in 12 patients, and the entry site was indeterminate in 14 patients. Pulmonary artery intramural hematoma was classified as Category 1 (n=18), Category 2 (n=10), or Category 3 (n=3). Additional imaging findings across the cohort included pulmonary artery stenosis in nine patients and hemopericardium in 24. There were no significant differences in mortality across different imaging findings. Conclusion: PH and AD are the two predominant etiologies of PAD. Notably, AD-associated PAD is frequently underdiagnosed and clinically underestimated. A comprehensive understanding of its pathophysiological mechanisms and characteristic CT patterns is essential for prompt diagnosis and optimal therapeutic decision-making.