Echocardiography is used to screen patients; however, over-reliance on a single estimation of pulmonary artery systolic pressure is unwise, instead multiple parameters should be assessed. 
echocardiography
Once a diagnosis of PH is made, radionuclide imaging should be performed to exclude chronic thromboembolic disease, and computed tomography is vital for eliminating parenchymal lung disease as a potential etiology. 
radionuclide imaging
Once a diagnosis of PH is made, radionuclide imaging should be performed to exclude chronic thromboembolic disease, and computed tomography is vital for eliminating parenchymal lung disease as a potential etiology. 
computed tomography
Currently, the primary contribution of cardiac MRI is the accurate assessment of right ventricular size and function.  In this respect, cardiac MRI may be supportive during diagnosis of PH, but the main importance of this is in defining prognosis although new outcome variables are anticipated.
cardiac MRI