Multimodality Imaging of Pulmonary Hypertension

PULMONARY HYPERTENSION Elevated pulmonary arterial pressures are the result of a spectrum of diseases that have been classified into 5 categories by the World Symposium on Pulmonary Hypertension. The finding of pulmonary hypertension (PH) is usually the first step in a multidisciplinary workup to diagnose the underlying cause, as different etiologies have different treatment algorithms and outcomes. Diagnostic imaging plays a key role in not only the initial evaluation of a patient with PH, but also to assess disease progression or treatment response. In trying to discover the underlying cause of PH, the diagnostic radiologist often must act as a detective. While some findings, such as varying degrees of enlargement of the pulmonary trunk and remodeling of the right heart, are ubiquitous in patients with PH, it is often the more subtle findings that can help elucidate the cause. These findings may be isolated to the lung parenchyma or may involve the pulmonary or systemic vasculature, heart, or mediastinum. The purpose of this article is to review the various findings of PH on computed tomography (CT) and ventilation/perfusion (V/Q) scans that can help one to differentiate between the various etiologies.