Page 111 - Assessing right ventricular function and the pulmonary circulation in pulmonary hypertension Onno Anthonius Spruijt

Introduction
Accurate assessment of right ventricular (RV) and arterial structure and function in pulmonary hypertension (PH) is essential for several reasons.
First, since direct visualization of the effects of the disease on the vessel wall is not possible, the assessment of disease severity and monitoring of therapeutic effects is only possible by studying the RV and pulmonary arterial function. Since the effects of treatment on RV and pulmonary arterial function are small, a prerequisite for such measurements is that they are accurate, reproducible, observer independent, and do not require geometric assumptions.
Second, the primary cause of death in most types of PH is RV failure. The diagnosis of early RV failure is thus of great clinical importance. In addition, the mechanisms of RV failure are currently poorly understood and can only be unraveled if the complex interaction between altered RV structure and function and the pivotal role of myocardial perfusion and metabolism on these parameters can be elucidated.
Thirdly, since it is known that most drugs used in the field of pulmonary arterial hypertension (PAH), not only act on the pulmonary vasculature, but also have an effect on the myocardium, discrimination of the effects of PH drugs on both the RV and the pulmonary vasculature are important.
Magnetic resonance imaging (MRI) and nuclear imaging techniques are both emerging techniques in the field of PH and offer novel possibilities to study the role of the RV in PH and the effects of treatment thereon. In addition, these techniques allow to determine the role of the different factors involved in RV failure, and subsequently to develop new therapeutic strategies. This chapter provides an overview of the application of MRI and nuclear imaging techniques in the field of PH and discusses future possibilities.
Magnetic Resonance Imaging
Quantification of Right Ventricular geometry and mass
In the early years of MRI, it was already recognized that this technique allows accurate measurement of the RV volumes [1-3]. Initially, the accuracy of global RV volume and function measurements was verified by using water-filled latex balloons and ventricular casts of excised bovine hearts [2].
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