Cardiovascular magnetic resonance for the assessment of pulmonary arterial hypertension: toward a comprehensive CMR exam.

Pulmonary arterial hypertension (PAH) is a progressive disorder characterized by abnormally increased blood pressure of the pulmonary circulation. The clinical course of the untreated PAH involves rapid progression to right ventricular (RV) failure and death. Right heart catheterization is the gold-standard method for confirming PAH. However, the technique's invasiveness and associated risks preclude its use on a regular basis. Different imaging techniques have been implemented for evaluating PAH, including echocardiography, computed tomography and nuclear medicine. However, these techniques have their own limitations. During the past decade, cardiovascular magnetic resonance (CMR) has been increasingly used for the evaluation of different cardiovascular diseases, including PAH, due to its high resolution, high tissue contrast, and the plethora of anatomical and physiological parameters that can be measured with this modality. This article presents an up-to-date review of the implementation of CMR for evaluating PAH. This is achieved by describing a comprehensive CMR protocol that includes several imaging sequences for assessing different cardiovascular parameters pertaining to PAH. In contrast to the previously published articles, the presented CMR protocol evaluates both RV function and pulmonary artery hemodynamics, which are both affected in PAH. Each imaging sequence is explained along with the image analysis steps required for deriving the cardiovascular parameters of interest. Then, based on an extensive literature review, the article illustrates the significance of the derived cardiovascular parameters and their association with PAH. The article concludes with a discussion of the advantages of the proposed CMR exam for better understanding of the disease pathophysiology and treatment planning.