Image Reconstruction with Time-Resolved Contrast Enhanced Magnetic Resonance Angiography

Contrast enhanced magnetic resonance angiography enables one to visualize the vascular system of the human body. Typically, using conventional measurement techniques, one three-dimensional volume of the vascular system can be measured during the passage of the contrast agent. More recently, medical doctors desire time-information of the blood-flow, or want to scan time-dependent phenomena. To enable this, scan-time has to be shortened. 3D-TRICKS [1] enables such scan-time reduction, however at the cost of a more complex image reconstruction. Last year [2], we introduced a new image reconstruction method incorporating prior knowledge on the time-course, i.e. a gamma-variate function, of the contrast agent through the blood-vessels. This enables improved image reconstruction compared to the method described in [1]. However, this method requires that the entire 3D volume follows the same time-behaviour as the blood in the blood-vessels, or that the non-blood-vessel contribution to the signal-strength is negligible. In in-vivo measurements this assumption appeared to be invalid. In this paper we introduce an improved version of our image reconstruction algorithm. The prior-knowledge is now assumed to be only valid inside the blood-vessels. The fitting procedure described in [2], is now only applied to the blood-vessels using segmentation. In vivo results using this new reconstruction method will be presented. Keywords— Magnetic Resonance Angiography, Contrast Agent, Time-Resolved, Image Reconstruction, Scan-Time Reduction