Ultra-Early Postmortem 3-T MRI of the Human Brain: A Two-Case Feasibility Study of Structural, Diffusion, and Vascular Imaging in Unfixed Cadavers

Background Cadaveric magnetic resonance imaging (MRI) permits high-resolution, motion-free characterization of neuroanatomy, but postmortem interval, tissue temperature, autolysis, and chemical fixation can alter relaxation and diffusion properties. Imaging rapidly after death and before fixation may reduce exposure to these time-dependent changes, but the feasibility of combining sub-millimeter structural imaging, advanced diffusion imaging, and vascular imaging on a clinical 3T platform remains incompletely characterized. We therefore assessed the technical feasibility of these acquisitions in a two-cadaver exploratory series. Methods This exploratory two-case feasibility series included two adult cadavers studied at a short postmortem interval on a clinical 3T MRI system. Acquisitions included T1-weighted MPRAGE, T2-weighted SPACE, susceptibility-weighted imaging, diffusion spectrum imaging, multi-shell diffusion-weighted imaging, and time-of-flight angiography. In one specimen, postmortem vascular perfusion with manganese chloride was followed by additional angiographic imaging. Structural, diffusion, and vascular datasets underwent modality-specific preprocessing, reconstruction, and visual quality review. Feasibility was evaluated descriptively; no inferential statistical tests or population-level effect estimates were performed. Results Sub-millimeter structural MRI and advanced diffusion imaging were acquired and reconstructed in both specimens. Whole-brain deterministic tractography was generated in both cases. In specimen 1, a focal structural abnormality compatible with a chronic lacunar infarct was accompanied by a visually reduced streamline representation in the corresponding region. In the perfused specimen, post-perfusion angiographic imaging enabled visualization and 3D reconstruction of major proximal intracranial vessels and showed reduced distal vascular opacification in the right middle cerebral artery territory. These focal structural, diffusion, and vascular observations were exploratory rather than prespecified diagnostic endpoints. Conclusions In this two-specimen series, ultra-early unfixed cadaveric MRI on a standard clinical 3T platform yielded interpretable high-resolution structural and diffusion datasets, with a technically usable vascular reconstruction in the perfused case. These findings support workflow feasibility but do not establish diagnostic accuracy, preservation of in vivo tissue properties, reproducibility, or generalizability.