Flow Sensitive 4D Magnetic Resonance Imaging: Analysis of 4D Blood Flow Characteristics in the Human Vascular System
Aurélien Stalder, University Hospital Freiburg, Germany

Seminar • 17 November 2008 • BM 5.202

Abstract
Magnetic Resonance Imaging (MRI) techniques provide a non-invasive method for the highly accurate anatomic depiction of the heart and vessels. In addition, the intrinsic sensitivity of MRI to flow, motion and diffusion offers the unique possibility to acquire spatially registered functional information simultaneously with the morphological data within a single experiment. Characterizations of the dynamic components of blood flow and cardiovascular function provide insight into normal and pathological physiology and have made considerable progress in recent years. The principles and limitations behind flow-sensitive MRI with ECG synchronization and respiratory control are briefly explained. Flow sensitive time-resolved 3D MR-Imaging using 3-directional velocity encoding for the detection and visualization of global and local blood flow characteristics in targeted vascular regions (aorta, cranial arteries, peripheral arteries) is presented. Blood flow characteristics in normal vascular geometries as well as for common pathologies were investigated using advanced computer aided data analysis which empowered the reader to take full advantage of the 4D nature (3 spatial and one temporal dimension) of the data. The comparison of vascular hemodynamics in volunteers and patients illustrates that even small pathological geometric changes such as mild aneurysms or prosthesis repair bear a major impact on local vascular hemodynamics and severely alter blood flow characteristics. Further quantification and analysis of derived vessel wall parameters may allow for a regional analysis of the impact of vascular pathologies on the vessel wall.