Development of Novel Physiological CMR Methods in Health and Disease

Physiological cardiovascular stress test plays a crucial role in the assessment of patients with suspected heart disease. There are several methods of cardiac physiological stress tests and each of them offer varied insight into cardiac physiological adaptation: passive leg raise, intra-venous fluid challenge, pharmacological stressors and physical exercise stress test. Echocardiography, which is the mainstay for the non-invasive rest/stress assessment of the left ventricular (LV) haemodynamics has several limitations. Novel methods of CMR imaging allow to map intra-cardiac flow in three-dimension using novel flow acquisitions. These novel flow acquisitions are called four-dimensional flow CMR, where the fourth dimension is time. Additionally, traditional cine CMR imaging for functional assessment can now be done without breath-holds using advanced acceleration methods, allowing them to be used during exercise. A comprehensive understanding of functional-flow coupling at rest, during increased pre-load (fluid challenge) to the heart or during exercise, is lacking in the literature. There is an important need to validate these novel CMR methods for developing mechanistic insight into physiological cardiac adaptation to increased pre-load or to exercise in health and how it alters in heart disease.