Postmortem imaging exposed: an aid in MR imaging of musculoskeletal structures.

OBJECTIVE

To identify factors that influence the quality of postmortem magnetic resonance (MR) images of musculoskeletal (MSK) structures as described in the literature, and to evaluate the extent to which these MR images are affected.

MATERIALS AND METHODS

Four useful studies were retrieved from a PubMed and EMBASE search, covering the literature up to 1 March 2012. Three additional studies were included after a manual search from reference lists.

RESULTS

Four human studies and three animal studies are considered in this review. Postmortem MRI quality can be affected by storage temperature, repeated freezing and thawing and fixation. Provided there was an adequate, but above-freezing storage temperature, postmortem changes in fresh cadavers did not appear to affect the MR image quality of MSK structures up to 14 days after death. Image contrast, signal intensities, and relaxation times are temperature-dependent, regardless of whether the specimen was fresh or postmortem for up to 7 days. Bad image quality can occur owing to accelerated autolysis. Freezing and thawing did not affect image quality, unless repeated too often, or whenever a heating pad was used to speed up the thawing process. Conventional formalin-based fixation leads to swelling of soft tissue and fluid accumulation in joints, and therefore to deteriorated images, with image quality just sufficient to visualize gross anatomy.

CONCLUSION

Various factors were identified that affect postmortem MR image quality of MSK structures. Postmortem MR image quality was good, except for images of the fixated specimen. Freezing is the preferred method of conservation for specimens that are to be subjected to postmortem MRI.