Blood pool imaging

Blood-pool or equilibrium phase imaging is ultra high spatial resolution imaging that requires a contrast agent (i.e., a blood-pool agent) that remains present in the vasculature for an extended period of time, leading to a prolonged reduction in T1 of blood.

Blood-pool agents have a much higher relaxivity compared to extracellular agents, resulting in a higher vessel-to-background signal. The longer intravascular half-life prolongs the imaging window from about 1 minute to approximately 1 hour. The advantage of this is that multiple arterial territories can be imaged after a single contrast injection, or, alternatively, a specific region of interest can be evaluated at a higher spatial resolution. It is possible to measure tissue blood volume and perfusion with blood-pool agents. Blood-pool agents also allow for evaluation of capillary membrane integrity, which is useful for the detection of slow bleeding. Blood-pool agent-enhanced MRA during the equilibrium phase also facilitates simultaneous evaluation of veins. Because the spatial resolution of steady-state images is typically much higher compared to first pass images, arteries and veins can easily be separated on the source images or multiplanar reformations. Furthermore, the simultaneous depiction of veins can actually assist preoperative planning by providing the vascular surgeon with information about the suitability of autologous veins for use as bypass grafts.

Created 08/09/2011 Last updated 19/03/2012