Table 3 Imaging investigations recommended in the assessment of pulmonary hypertension (PH)
Chest x rayMay show increase in cardiac chambers, increased pulmonary artery size, hypoperfused areas of lung and evidence of parenchymal lung disease
High resolution computed tomography (CT) scan of lungsMay show parenchymal lung disease, mosaic perfusion (a sign of pulmonary vascular embolism or thrombosis but for which there are other causes such as air trapping), and features of pulmonary venous hypertension
CT pulmonary angiographyUsed to look for enlargement of pulmonary arteries, filling defects and webs in the arteries. Detects enlarged bronchial circulation
Ventilation perfusion scanningMore sensitive for chronic pulmonary thromboembolism than CTPA but not helpful when there is underlying parenchymal lung disease
Selective pulmonary angiography by direct injection of the pulmonary arteriesGold standard for delineating chronic pulmonary thromboembolism to define the location and extent of disease. It may be superseded by magnetic resonance angiography or multislice CT.
EchocardiographyScreening tool of choice for PH. Detects cardiac disease (congenital, myocardial, valvular, intracavity clot or tumour, pericardial). Use of contrast may be helpful to identify shunts
Cardiac magnetic resonanceGood examination for imaging the right ventricle. Helpful in delineating congenital heart defects, and the pulmonary circulation by angiography
Abdominal ultrasoundUsed for investigation of liver disease and suspected portal hypertension.