High resolution computed tomography of the chest
High resolution computed tomography of the chest (HRCT) supplies detailed information about underlying lung parenchyma disease, such as pulmonary emphysema or interstitial lung disease. A number of various pathologic features may be detected on chest HRCT including pericardial effusions and pulmonary artery enlargement, defined by the ratio of the diameter of main pulmonary artery to that of the thoracic aorta >1. In the setting of CTEPH, contrast HRCT of the pulmonary arteries may show changes like complete vessel obstruction, vessel cut-offs, intimal irregularities, incorporated thrombus formations as well as bands and webs [189]. Furthermore, collaterals from bronchial arteries can be identified with this technique. Proximal pulmonary obstruction is displaying about significant and accessible organized fibrous tissue in segmental or subsegmental arteries. If no proximal obstruction or obliteration is noted; lesions are considered to be distal, non-accessible to surgery intervention. In some cases, pulmonary angiography is necessary to differentiate between proximal or distal obstructions. Chest HRCT may also suggest PVOD in the presence of adenopathy mediastinal, ground glass opacities and septal lines [53].