To our knowledge, the use of MDCTA for the diagnosis of a condition of pulmonary arterial origin has received little attention in the literature, with only a few case reports.15–16 In our series, the signs of pulmonary arterial hemoptysis determined by MDCTA were PAA or PAPA (n = 8) and pulmonary artery within the inner aspect of a cavity wall (n = 5). In fact, the MDCTA results depended on the underlying disease. The potential causes of pulmonary arterial hemoptysis are numerous and include all pathologic processes, such as pulmonary necrosis (eg, active tuberculosis, pulmonary abscess, aspergillosis, and necrotic cavitary from lung carcinoma), vasculitis (eg, Behçet disease or Hughes-Stovin syndrome), trauma from a by Swan-Ganz catheter, and pulmonary arteriovenous malformation. The pulmonary embolism is not a cause of pulmonary arterial hemoptysis; in fact, the pulmonary embolism provokes a lung ischemia leading to systemic hypervascularization by bronchial arteries. In this case, the direct hemoptysis source is the bronchial artery hypervascularization and not the pulmonary artery injury. The hemoptysis source in the patient with pulmonary emboli is the bronchial arteries as a consequence of the lung ischemia, the bleeding source. In our patients, MDCTA suggested diagnoses of vasculitis (n = 2), tuberculosis (n = 3), Aspergillus infections (n = 2), lung cancer (n = 1), and Hodgkin lymphoma (n = 1). In the remaining four patients, the etiologic diagnosis was known before the onset of hemoptysis.