CTpulmonale

CTpulmonale, commonly referred to in clinical practice as CT pulmonary angiography (CTPA), denotes computed tomography imaging of the pulmonary vasculature. It is the preferred imaging modality for diagnosing acute pulmonary embolism (PE) and for evaluating thoracic symptoms when PE is a consideration. The technique involves intravenous administration of iodinated contrast and rapid, helical CT image acquisition timed to the arterial phase, often with reformations in multiple planes. Some centers use dual-energy CT to assess pulmonary perfusion.

Findings on CTpulmonale include intraluminal filling defects within pulmonary arteries, ranging from main to subsegmental branches, consistent with emboli. The sensitivity is highest for central emboli but can be limited for very small subsegmental clots. Associated signs of right ventricular strain, such as an enlarged right ventricle, flattening or bowing of the interventricular septum, and enlargement of the main pulmonary artery, may indicate worse prognosis. Additional CT findings can include atelectasis, pleural effusions, or wedge-shaped infarcts. CT pulmonary imaging may also reveal alternative diagnoses such as pneumonia, pneumothorax, or aortic pathology.

Indications and limitations: CTpulmonale is indicated in patients with acute chest pain or dyspnea and suspected PE when clinical probability or D-dimer testing warrants imaging. Limitations include radiation exposure and risk of contrast-induced nephropathy or allergic reactions to iodinated contrast. In pregnancy or in unstable patients, alternative imaging modalities may be considered. Subsegmental PE can be challenging to interpret; management decisions should consider the overall clinical context.

Clinical utility: A negative CTpulmonale reduces suspicion for PE, while a positive scan confirms PE and guides anticoagulation decisions and risk stratification.