Noninvasive imaging for the diagnosis and prognosis of pulmonary hypertension

Pulmonary hypertension (PH) is a major cause of morbidity and mortality, but it often presents with nonspecific symptoms, thereby delaying diagnosis and treatment. While invasive cardiac catheterization is essential to confirm the diagnosis, patients with breathlessness are commonly encountered in clinical practice creating a demand for noninvasive screening methods. Preliminary investigations such as the electrocardiogram and chest radiograph lack sensitivity even in advanced cases. 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. 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. 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.