Bodies of evidence: the quest to improve post-mortem imaging
Nature is unkind to decomposing bodies. Muscle, skin and internal organs slacken and lose their form as time, temperature and other factors drive the slow, inexorable process of decay.
Tissue breakdown brings with it substantial changes in chemical composition and physical properties, explains Natalie Adolphi, PhD, who is exploring ways to enhance magnetic resonance imaging (MRI) of human corpses.
The same MRI methods that allow doctors to get detailed images of soft tissue in living patients don’t work as well once tissue cools and decomposition sets in, explains Adolphi, a research associate professor in the Department of Biochemistry and Molecular Biology.
“My goal is to understand the effect of post mortem changes in both temperature and time since death,” Adolphi says, “and then be able to account for those by adjusting imaging protocols to give high-quality images that could then be used diagnostically to aid in determining things like the cause and manner of death.”
Adolphi has teamed with pathologist Kurt Nolte, MD, director of UNM’s Center for Forensic Imaging in the Office of the Medical Investigator, and radiologist Gary Hatch, MD, the center’s assistant director, to conduct tissue experiments using OMI’s 1.5-Tesla MRI scanner.
In work funded by the National Institute of Justice, the trio has conducted experiments on animal tissue (a byproduct of food production) – mainly pig tissue, because it most closely resembles human tissue. Adolphi experimentally adjusts the scanner’s sampling rate to compensate for temperature and time post mortem to obtain the highest quality image, creating a reference standard for pathologists to use.
New Mexico’s OMI, which handles all autopsies in the state, is unique in the U.S. for having both a clinical MR scanner and clinical CT scanner in the autopsy suite, Adolphi says. “It really makes possible a level of access for forensic investigation that just normally wouldn’t be available at other medical examiner’s offices.”
The forensic imaging center is a partnership between the Departments of Radiology and Pathology, the School of Medicine and OMI, says Nolte, who has performed or supervised more than 4,000 conventional autopsies. “The purpose of the center is to really foster interdisciplinary and multispecialty research, as well as provide support for clinical imaging,” he says.
Pathologists performing autopsies sometimes encounter serious obstacles due to severely decomposed tissue, Nolte says. “To be able to adjust MR scanners so that they can image tissues that are decomposed, too hot, too cold – all of the different variables –so that forensic pathologists can then get a window into anatomy that may be difficult to dissect, is very important.”
Hatch, who studied “virtual autopsy” techniques in Switzerland before coming to UNM three years ago, helps Adolphi identify changes in anatomical structures in her research. The Swiss, he says, want to see how much of the traditional autopsy method could be replaced by digital tools that include medical imaging, laser scans and high-resolution color photos.
Adolphi believes the research holds tremendous potential. “The next level would be a new grant further down the road that takes the methods we have developed in this basic study and applies them in a rigorous and systematic way to human subjects,” she says.