Virtual autopsies

Traditional autopsies are considered as invasive procedures by many faiths and even violate religious laws, such as is the case for Muslims and Jews. This is why the concept of virtual autopsy, which relies on computer tomography (CT) and magnetic resonance imaging (MRI) technologies, has been developed in the last two years.
Written by Roland Piquepaille, Inactive

Traditional autopsies are considered as invasive procedures by many faiths and even violate religious laws, such as is the case for Muslims and Jews. This is why the concept of virtual autopsy, which relies on computer tomography (CT) and magnetic resonance imaging (MRI) technologies, has been developed in the last two years. Engineers from Silicon Graphics (SGI) are working with the authorities of countries such as Switzerland or Sweden to provide better views of fatal injuries while treating the deceased people with respect. But this kind of virtual autopsy has other applications, such as for armed and police forces. It also can be used to determine the cause of the death of a victim of a natural disaster like a hurricane, when dead bodies are already badly decomposed. And virtual autopsies also can reduce postmortem costs. While a traditional autopsy can cost up to $5,000, a virtual one costs only about $1,000. So far, only a thousand of virtual autopsies have been performed worldwide, but this number is increasing quickly.

In this press release, SGI describes the technologies at work behind a virtual autopsy.

Virtual autopsy -- also called Virtopsy in Switzerland -- uses Computer Tomography (CT) and Magnetic Resonance Imaging (MRI) technologies to capture detailed X-rays and MRI images of the deceased’s body. Radiologists then create full 3D visualizations of the deceased, which allow pathologists, coroners and medical examiners to examine the condition of bones, tissues, organs and blood vessels for clues to the cause and manner of death.

In "Dead Men Do Tell Tales," Technology Review provides additional details.

A virtual autopsy begins with either a computer tomography (CT) or a magnetic resonance imaging (MRI) scan -- the same systems used in hospitals. Then a graphics workstation compiles the "slices" of data collected in the scans into a single three-dimensional visualization -- a rendition that's beyond the capabilities of standard software used for visualizing CT and MRI results. Full-body scans take approximately 20 seconds, while the graphics workstations can compile the data into a navigable 3-D image within one minute.

Before going further, below are three images provided by SGI and which appear courtesy of NASA/Stanford Biocomputational Center, Volume Graphics GMBH, and SGI. First is a screenshot showing how experts are working with these stacks of scanned images.

Working with a skull: screenshot

Then here is a full cross-section of the same skull.

Cross-section of a skull

Finally, here is the full structure of a skull, from which the experts will be able to draw their conclusions.

Full structure of a skull

SGI was one of the sponsors of "New Advances in Post-Mortem Radiology," a two-day conference hosted by the Royal Australian College of Radiologists (RACR) held last month. [Here is a link to the conference's program (PDF format, 5 pages, 156 KB).] The chairman of the conference tells us why virtual autopsies are useful.

"All cultures have funeral customs, and many find invasive post mortems offensive to those customs and values," said Graham Segal, OAM, a barrister-at-law and chairman of the radiology conference. "Yet most recognize that there are times when this process is necessary. This conference will explore technologies that help reconcile these considerations by providing a non-invasive procedure that may be of value in many cases."

SGI also lists a number of applications where virtual autopsies could help.

The technology also offers promise to many medical centers equipped with CT and MRI machines but lacking forensic pathologists. Scans can then be sent to pathologists who can conduct autopsies remotely. In addition, the technology promises to ease the burden of determining identity and cause of death in victims of large-scale hurricanes, earthquakes or other natural disasters, particularly in cases where bodies are badly decomposed. For Homeland Security and global anti-terrorist organizations, the technology also can significantly ease forensic and law enforcement efforts to quickly and accurately pinpoint the chain of events after a bombing or other terrorist attack.

Technology Review gives us some practical details on how this technology is used at the Center for Medical Image Science and Visualization (CMIV) in Linköping, Sweden.

At CMIV, researchers use a system created by SGI (Silicon Graphics) to process the images, and then view them remotely across Sweden through what SGI calls a visual area network. The visualizations can be displayed on any type of computer because the graphics processing is done entirely on the SGI server. The system allows medical professionals throughout the country to learn from the most interesting cases, according to Afshad Mistri, senior manager of advanced visualization for SGI.

In "Cutting edge, without a scalpel," the San Francisco Chronicle tells us how much it costs to perform a virtual autopsy.

Virtual autopsies also help lower postmortem costs. Mistri of SGI said a regular autopsy costs about $4,500 to $5,000, compared with about $900 to $1,000 for a virtual autopsy. Autopsies are generally paid for by the legal jurisdiction, such as a county, that is requiring the procedure.

So will this new technology be accepted? The Chronicle answers.

The growing acceptance of virtual autopsies is due in part to the emergence of a new generation of doctors and medical examiners who, unlike their predecessors who spent most of their careers looking at two-dimensional X-ray images, grew up in the world of 3-D visualization. Mistri calls them the Nintendo Generation.

And Dr. Michael Thali of the Institute of Forensic Medicine at the University of Bern in Switzerland is very enthusiast about the 3-D visualization technology used for virtual autopsies.

"The classical approach is still to look at slices in 2-D," he said. "But I think the 3-D visualization is becoming more and more important to visualize the findings in 3-D. In our area dealing with forensic radiology, where you have to present your findings not to medical doctors but to the people in courts with no medical backgrounds, it's very useful that you can visualize or demonstrate your findings in 3-D."

For more information about the concept of Virtopsy, a name registered by Thali's group, please visit their web site, which motto is "modern imaging technology for the benefit of forensic science."

[Disclaimer: I worked in the past for SGI, but right now, I don't have any ties with this company.]

Sources: SGI press release, November 7, 2005; John Gartner, Technology Review, November 23, 2005; Benjamin Pimentel, San Francisco Chronicle, November 28, 2005; and various web sites

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