Multimodality Imaging of Pulmonary Hypertension

Purpose of review: Pulmonary hypertension (PH) is a complex, progressive abnormal physiologic and hemodynamic state seen in many conditions. The purpose of this review is to discuss the updated clinical and hemodynamic classification systems and diagnostic criteria of PH, discuss the role of noninvasive imaging for diagnosing PH, and outline a diagnostic pathway to facilitate targeted therapies. Recent findings: PH is defined as a mean pulmonary arterial pressure (mPAP) > 20 mmHg since the sixth World Symposium on Pulmonary Hypertension (WSPH) in 2018, a lower threshold than the longstanding definition of mPAP > 25 mmHg. Additionally, in 2018, Truong et al. established a four-tier classification for the diagnosis of PH based upon the degree of main pulmonary artery enlargement on computed tomography, whereby the likelihood of PH increases with increasing tier severity. Other noninvasive modalities, particularly echocardiography and cardiac magnetic resonance imaging (CMR), aid in prognostication of PH and drive clinical decision-making and treatment strategies. Summary: Multimodality imaging is paramount in the screening, diagnosis, and management of PH by providing anatomical, physiologic, functional, and prognostic information. Cumulative findings on echocardiography, ventilation/perfusion scintigraphy, computed tomography, and CMR imaging can often identify the etiology of PH and provide insight into pathophysiology and disease stage.