Diagnostic algorithm for chronic thromboembolic pulmonary hypertension. Diagnostic algorithm for chronic thromboembolic pulmonary hypertension. CT: computed thomography; CTEPH: chronic thromboembolic pulmonary hypertension; PAH: pulmonary arterial hypertension; PH: pulmonary hypertension; V/Q: ventilation/perfusion. aCT pulmonary angiography alone may miss diagnosis of chronic thromboembolic pulmonary hypertension. Nazzareno Galiè et al. Eur Respir J 2015;46:903-975 ©2015 by European Respiratory Society