In Vivo Contrast-Enhanced (Gd-DTPA) and Ex Vivo Magnetization Transfer and Diffusion Weighted MRI Detect Changes in Thrombus Composition During Propagation from Sites of Disrupted Atherosclerotic Plaques.

Alkystis Phinikaridou¹, Kevin J. Hallock², Ye Qiao¹, James A. Hamilton¹

We combined gadolinium-enhanced in vivo and ex vivo magnetization transfer (MT) and diffusion weighted (DW) MRI to study thrombus formation associated with vulnerable plaques in rabbits. We found that: (i) thrombi propagate parallel and anti-parallel to blood flow from the site of plaque disruption, (ii) in vivo use of Gd-DTPA distinguished the thrombus from the underlying plaque, (iii) ex vivo MT and DW imaging detected changes in thrombus composition during propagation. As thrombi propagate they become enriched in fibrin and circulating blood cells resulting in increased % MT ratio and decreased apparent diffusion coefficient.