Why Give a Dead Man a Body Scan?

Postmortem Exam Technician Gabriel von Allmen slides a body into a computed tomography (CT) scanner at the University Medical Center in Bern, Switzerland. John B. Carnett

View Photo Gallery

A light shines under the closed door of a radiology suite, down a darkened hallway deep inside the University Medical Center in Bern, Switzerland. Outside the building, under the glow of a fluorescent street lamp, an empty hearse waits in the loading dock. Tonight the local undertaker is earning some extra money making a special delivery. Entering the radiology room through a back door, he gently deposits a body—double-wrapped inside a blue bag—on the sliding bed of a full-body scanner. The bag, through which x-rays can easily pass, will remain closed while the body is scanned, both to respect the privacy of the dead and so as not to disturb any nonforensic personnel in the room.


Without the bag, the university’s Institute of Diagnostic Radiology would not have approved the use of its aseptically clean research facilities for postmortem studies, says forensic pathologist Michael Thali. The Swiss emphasis on orderliness and precision extends to the task of death investigation.


This cultural passion—some would say obsession—for precision becomes clear to any visitor arriving by train here in Switzerland’s 800-year-old, meticulously preserved capital. Rows of clocks line the train station corridor, all perfectly synchronized down to the sweep of their prominent second hands. In this spirit, Thali and his colleagues at Bern’s Institute of Forensic Medicine are perfecting the ultimate no-mess autopsy: precise, objective and nondestructive, with death’s every data point captured permanently on compact discs that the scientists store in the vault of a nearby Swiss bank (where else?).


Thali calls the technique “virtopsy,” or virtual autopsy. Specifically, his research team has adapted the twin medical- imaging technologies of computed tomography (CT) and magnetic resonance imaging (MRI) to create three-dimensional, high-resolution computer images of a crime victim’s internal organs. Thali pours these digitized blood and guts into a hollow-man replica of the victim. The result is a head-to-toe cybercorpse that a pathologist can view—wounds and all—from any depth and angle, including inside out.


Besides being a bloodless approach to an otherwise messy job, the digitally preserved bodies of the Virtopsy Project have the added benefit of permanency. “Murder victims have the unfortunate habit of decomposing,” Thali notes. Of course, police and pathologists have long documented such disappearing evidence with photographs and detailed medical reports. Photos, however, are limited by their two-dimensionality and the inherent distortion of camera angles. And medical reports, according to Thali, remain unacceptably subjective.


It’s a criticism supported by the cacophony of the courtroom, where prosecutors and defense lawyers often present dueling pathologists, each reinterpreting autopsy reports to favor one side or the other. Complicating a jury’s difficulty in following such arguments are the typically gore-drenched autopsy photos that prompt many to turn away in horror. “We [in Switzerland] are not so used to shows like CSI,” Thali points out. “It can be a real problem.”

In the future that Thali envisions, any pathologist taking the witness stand can bloodlessly redissect the victim in full view of the jury by calling forth the original data stored on the discs. “Graphic, yes. Gory, no,” he says.


Over the past three years, Thali has performed more than 100 virtual autopsies, each followed by a traditional autopsy to confirm his findings. Although his experimental technique has proved highly accurate, he expects to complete at least 100 more cases before the first virtopsy debuts in a court of law.


“Virtopsy is still like a little baby,” Thali says. “It is not yet ready to stand alone.” First he must show that it is at least as accurate as traditional autopsy. So far, he says, virtopsy has been particularly good for detecting the internal bleeding, bullet paths and hidden fractures that can be maddeningly difficult to
isolate amid the mass of blood and gore that results when a pathologist is forced to essentially eviscerate the body.


Best of all, perhaps, is the way CT and MRI scans highlight emboli—air bubbles that obstruct blood vessels and that have most likely entered the body through a wound of some sort. Such effervescent evidence can vanish as soon as a pathologist slices open a vein or organ to look for it, Thali explains. “So difficult is this problem that some have proposed performing underwater autopsies in swimming pools to detect escaping air bubbles,” he says.
The scans also make it much easier to detect aspirated, or inhaled, water and blood in the lungs. These forensic “vital signs” tell a pathologist that a victim was alive when he entered the water or sustained an injury, which can be crucial for determining whether an apparent drowning or car crash was staged to cover up a murder. Pockets of air, blood or water show up clearly on CT and MRI scans as spots—black, bright white or gray—against the background of body tissues.


On the negative side, virtopsy remains woefully inadequate for diagnosing poisoning, as well as common natural causes of death such as infection or heart failure. “Obviously,” Thali admits, “it’s very important to be able to rule out such natural causes in a case of suspected murder.”