Imaging techniques in chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) can affect up to 4-5% of patients with acute pulmonary embolism. It is likely an underdiagnosed entity. Misdiagnosis is common because patients often present with nonspecific symptoms of pulmonary hypertension. Early diagnosis may help improve the outcome, as CTEPH is potentially curable with pulmonary thromboendarterectomy (PEA). Imaging is central to an accurate diagnosis, and for assessing correctly the technical feasibility of PEA. This review examines the findings of various imaging techniques in CTEPH and their contribution in the diagnostic and therapeutic evaluation of the disease.

Ventilation-perfusion scintigraphy remains a sensitive method for excluding CTEPH. Multidetector computed tomography angiography (MDCTA) depicts directly changes of CTEPH, provides a surgical 'road map', and should be used for the diagnostic assessment of all suitable patients with pulmonary arterial hypertension. In many centers, the role of conventional pulmonary angiography is gradually being replaced by cross-sectional methods. MRI has a role in preoperative and postoperative assessment of right ventricular function and can depict vascular abnormalities up to segmental level.

MDCTA in combination with MRI represent the main techniques for the diagnosis and management of CTEPH. Newer techniques such as dual spectrum computed tomography may further improve preoperative and postoperative assessment of CTEPH patients.