The emerging role of magnetic resonance imaging in the diagnosis and management of pulmonary hypertension.

Pulmonary hypertension is a life-threatening chronic disorder of the pulmonary circulation. Elevated pressure and resistance in the pulmonary vessels lead to progressive right heart failure which results in functional limitations and ultimately the death of most patients. Thus, the monitoring of right ventricular (RV) function is of great importance. Cardiac magnetic resonance imaging (cardiac MRI) has several advantages over other imaging methods. The use of cine acquisition techniques allows precise description of characteristic volumetric and functional variables, such as right ventricular volumes, muscle mass, stroke volume, ejection fraction, or cardiac output. Impaired right ventricular contractility and function have also been assessed using measures like ventricular septal bowing and pressure-volume loops. MRI investigations have been performed to monitor medical treatment, and the improvement in well-established prognostic factors, such as the 6-min walk, were correlated with measures of right ventricular function. Flow-derived parameters of the pulmonary arteries (such as peak velocity, acceleration time and volume, or pulmonary flow profile) are available using velocity-encoded imaging, and may detect early signs of remodelling. Additionally, magnetic resonance angiography is a promising new tool to visualise pulmonary perfusion and to diagnose chronic thromboembolic pulmonary hypertension. The purpose of this review is to summarise recent advances of cardiovascular magnetic resonance imaging, which will play an increasing role in the comprehensive diagnostic work-up of patients with pulmonary hypertension as a tool to monitor the course of the disease and to evaluate new therapeutic approaches. (c) 2008 S. Karger AG, Basel.