Utilizing Blood Clots as Intrinsic Contrast Agents in Postmortem Vascular MRI at 7T

Motivation: While in vivo vascular imaging is well-characterized, the imaging features of vascular morphology and properties in postmortem brain samples remain poorly understood. Goal(s): To characterize postmortem brain vascular MRI features compared to in vivo imaging. Approach: We hypothesized to use blood clot as intrinsic contrast and use high-resolution T2*-weighted gradient echo imaging on both clinical and preclinical 7T scanners, with histopathological staining to validate blood clot formation. Results: Postmortem blood vessels showed contrast patterns similar to in vivo Ferumoxytol-enhanced SWI, particularly in smaller vessels, suggesting distinct changes in blood properties after death. Impact: The imaging characteristics of postmortem blood clots on T2*-W MRI enable detailed mapping of brain small vessel architecture, with contrast similar to in vivo Ferumoxytol-enhanced imaging, offering a novel method to study postmortem vasculature and imaging correlates to vascular pathology.