Cardiovascular Magnetic Resonance Imaging

Cardiac magnetic resonance imaging (CMR) has become one of the leading diagnostic procedures in cardiovascular medicine. It provides high spatial and temporal resolution of the beating heart. Among others, the strengths of CMR in clinical routine are detecting coronary artery disease with highest diagnostic accuracy, characterizing heart valve disease and unraveling cardiomyopathies in detail. Due to continuous improvement of applied physical methods and algorithms even microstructural morphology can be revealed nowadays. The CMR research team at the University Hospital Zurich, lead by PD Dr. Robert Manka, together with the Institute for Biomedical Engineering at the University and ETH Zurich, lead by Prof. Dr. Sebastian Kozerke, has worked on improving CMR techniques and translating research knowledge into clinical practice.

Fig 1. Flow visualization in a dilated Aorta.tif
Fig 1. Flow visualization in a dilated Aorta

Projects encompass detection of cardiac perfusion (coronary artery disease) using high resolution 3D techniques and its quantification. Another project deals with flow and flow patterns in patients with aortic stenosis before and after aortic valve replacement (Fig. 1). The conversion of different energy forms and states is of major interest, both, when the flow passes the aortic valve as well as it travels through the aorta. The research project adds to the knowledge why some patients with a specific flow pattern develop a dilated aorta while others do not. Different aortic valve replacements can be judged with respect to their hemodynamic efficiency calculating the energy loss of flow caused by the replaced valves. Even a better characterization of symptomatic and asymptomatic patients presenting the same degree of aortic stenosis seems to be possible.

Myocardial-fiber-characterization.jpg
Fig. 2. Myocardial fiber characterization

A third project investigates hypertrophic and non-hypertrophic cardiomyopathies. Besides describing macroscopic morphology and fibrosis patterns, the architecture of myofiber aggregates can be characterized at different time point in the cardiac cycle (Fig.2). The project offers answers why hearts suffering from a cardiomyopathy show a less effective way of cardiac contraction than healthy hearts do.

In recent years many research results of the Zurich CMR imaging group have been transferred into clinics, helping to make everyday CMR procedures more effective and successful. Among the methods has been the implementation of 3D-perfusion and 3D-late enhancement (fibrosis detection) protocols. Various projects have been conducted in close cooperation with co-investigating sides: e.g. London, Leeds, Berlin, Boston, and Aachen.