Figure 1.

Approach to CTEPH diagnosis. Patients with suspected CTEPH should first undergo a VQ scan, which can effectively rule out the disease due to its high sensitivity. Due to the low specificity of VQ scan, the next step is a CTPA, which confirms the diagnosis of CTEPH in patients with proximal disease. For patients with distal disease, pulmonary angiography aids in the planning of PTE or BPA at expert centers. *Some patients may have findings on CTPA consistent with alternative diagnoses, such as sarcoidosis or mediastinal fibrosis, in the absence of other typical CTEPH findings, such as mosaicism and bronchial collaterals.