Expanded role envisioned for imaging in autopsies

2006 05 12 15 01 23 706

In recent years, innovations in radiology and imaging technologies have transformed the process of diagnosing and treating the sick and injured. But despite those advances, one thing still holds true: radiology professionals, on the whole, work with the living.

That, however, may be changing as well. Several years ago, researchers in Bern, Switzerland, launched an ambitious project to leverage radiology and imaging techniques to conduct postmortem examinations without disturbing the body or its contents.

Dr. Richard Dirnhofer, director of the University of Bern's Institute of Forensic Science, envisioned a noninvasive, digital alternative to the traditional autopsy. Such a process, Dirnhofer concluded, would be invaluable to pathologists, medical examiners, and coroners to correlate the findings of traditional autopsies with high-resolution CT scans and MR data.

Over the years, the researchers in Bern have amassed a digital record of more than 120 individuals. Led by Dirnhofer and program chief Dr. Michael Thali, the Swiss team uses high-resolution CT scans, MR images, MR spectroscopy readings, and a 3D optical surface scanner to record each aspect of the body's solid, soft and surface tissues. With hardware and software that converts CT slices and other data into detailed 3D volumes that can be viewed interactively, the team has been able to view an entire body from inside out, localizing the specific areas of interest that can lead to a vital conclusion about cause of death.

An autopsy alternative

Now more than ever, the traditional autopsy cries out for an alternative. The process is invasive -- many would say grisly -- and is distressing to already grieving family members. Today's postmortem procedures are particularly objectionable to the billions of people whose religious beliefs strictly prohibit desecration of a deceased's remains except in the most extreme circumstances.

Orthodox Judaism, for instance, prohibits disturbing dead bodies except when such action may save others. Except in rare cases, autopsy practices such as organ removal should be avoided. Islam, too, is opposed to desecrating or even exposing the body of a deceased believer.

Other problems abound:

  • Autopsy photographs entered into evidence in criminal cases are often gory and can be difficult for jurors to view and understand.

  • Autopsy records, such as tissue sections, are difficult to store indefinitely.

  • Once an invasive autopsy takes place, the body cannot be reassembled to its original state, thus precluding another pathologist from conducting a new analysis on the same body. And in the case of violent crime, some body parts cannot be dissected, as they are considered evidence.

  • As potential global pandemics such as avian influenza (H5N1) increasingly pose a threat to more populations, the practice of eviscerating the victims of a deadly biological outbreak can pose serious health risks to coroners, pathologists, and medical examiners.

  • Following autopsies, organs and other remains are sometimes used for medical experiments, without the consent of next of kin.

Postmortem radiology examinations may well help overcome some of these challenges. The new procedure could provide medical and legal professionals with digital records that can be viewed in any location and at any time. Unlike physical samples, the records remain intact over several years, and can be transported electronically.

The technology also may offer relief to smaller medical centers equipped with CT and MRI machines, but lacking forensic pathologists. Scans captured with existing equipment -- no additional investment is required -- can be sent to pathologists who can conduct autopsies remotely.

It may also ease the burden of determining identity and cause of death in victims of large-scale hurricanes, earthquakes, tsunamis, or other natural disasters, particularly in cases where bodies are badly decomposed. For global antiterrorist organizations, the technology also can help forensic and law enforcement efforts to quickly and accurately pinpoint the chain of events after a bombing or other terrorist attack. And victims of contagious diseases and epidemics can be examined without putting medical personnel at risk.

Postmortem radiology solutions also could help judicial proceedings. Interactive visualizations of the deceased can be transported to courtrooms, are often easier for juries to understand, and can spare observers from having to view the graphic photographs that result from traditional autopsies. Digital postmortems also can provide attorneys and other court officers with a clearer understanding of the autopsy process, which can be vital when the manner of death must be established in a court case.

A global effort

Since researchers at the University of Bern began their seminal work, others have followed suit. In November 2005, the Royal Australian College of Radiologists hosted a two-day conference to review recent advances in using radiology to conduct postmortems.

The conference drew participants -- radiologists, pathologists, medical examiners, forensic scientists, legal experts, religious scholars, and technology leaders -- from all over the world to share methodologies and lessons learned from postmortem radiology projects in the U.K. and throughout Europe, Australia, U.S., and elsewhere. Conference organizers even invited leaders of various religious faiths to spotlight the sensitivities to invasive autopsy shared by people around the world.

The conference underscored that while digital autopsies are still in their very early stages, the science is moving forward. Leading-edge innovators, many of whom scan bodies at night when imaging equipment is not in use, are forging a future for postmortem radiology.

Worldwide, nearly 1,000 bodies have been scanned for postmortem examinations. Virtual autopsy procedures have helped military medical examiners solve the problem of determining exact cause of death for soldiers killed in the line of duty and others who have died in the war on terror. The U.S. Armed Forces Institute of Pathology, for instance, has scanned some 800 bodies to provide pathologists with MDCT data on soldiers killed in combat. The studies allow them to estimate kinetic energy sustained by the body and to run detailed analyses of metal fragments.

Another forensics institute, this one in Australia, recently purchased a 16-slice CT scanner, an image management system, and a data storage system to begin an initiative to create digitally scanned records of every deceased person referred to the institute. Even early in its implementation, the new system proved invaluable: Authorities seeking evidence of a suspicious death were able to exhume and scan the remains of a woman without ever having to open her casket. In the next year, that same institute plans to scan up to 4,500 bodies.

Using CT scans for postmortem studies has proved successful in Sweden, as well. There, pathologists couldn't determine why a 6-month-old boy died in surgery. But a digital postmortem conducted by a Swedish medical imaging institute revealed that a surgical instrument had tragically punctured the boy's heart.

Scanning the dead can also yield some unexpected surprises, even for well-equipped facilities. Victims of fire or drowning can bloat substantially, and badly burned bodies are often locked in contorted postures. This can prevent efficient scanning in many of today's CT and MR units. One forensic institute learned this when a badly burned body arrived at the facility. The deceased's arms were twisted enough to prevent the scanner from passing over the torso. Institute planners realized that, had they selected a scanner with a wider diameter, the postmortem scan wouldn't have posed a problem.

A new era ahead?

For a new era of digital autopsies to truly emerge, several forces must work in unison.

Medical professionals and legal authorities must determine standard protocols for scanning and storing data. Legal systems around the world must accept the admissibility of imaging evidence in determining the cause and manner of death. And as a new field, postmortem radiology will require special training.

Radiologists, for instance, are trained to interpret images of living patients. But the dead often look different; severe trauma or the effects of decomposition can displace organs. Understanding these differences will require knowledge and expertise that doesn't exist on a widespread basis today.

And while much can be accomplished using existing devices, technology providers are working on new tools to overcome the long-term challenges that are certain to arise.

New high-resolution scanners -- such as 64-slice CT systems -- create more data that must be processed and stored for months or years. But due to patient privacy regulations such as U.K.'s National Health System (NHS) Confidentiality Code of Practice, today's imaging facilities generally aren't set up to store CT or MR images for longer than a few days. This is fine for living patients, but it won't address long-term storage of terabytes or even petabytes of data.

An online and offline digital storage solution would address data storage needs not only for today's imaging equipment, but also for the even higher-resolution devices of tomorrow. Larger scan data, however, also makes it tougher for computers to convert 2D images into interactive 3D visualizations. New affordable visualization technologies may also hold the key to working with the large datasets that digital autopsies will produce.

That same data must also be securely transported to courtrooms or other pathology facilities. For this, forensic agencies could adopt a technology that Silicon Graphics (SGI) of Mountain View, CA, developed for the oil and gas industry called the visual area network (VAN). Using a VAN, a pathologist, coroner, or medical examiner can view a postmortem visualization in any location using any type of computer -- all without physically transferring the large files from one place to the next.

2006 05 12 15 01 11 706
A high-resolution 3D model could allow pathologists to examine an entire body from the inside out, while isolating specific areas of interest. This model of a human skull was rendered on an SGI Prism visualization system using Volume Graphics software. Images courtesy of NASA/Stanford Biocomputational Center, Volume Graphics GMBH, and SGI.

Full-body scans could also pose a problem for typical computer displays. Viewing a high-resolution postmortem on a computer screen can be like reading a map through a keyhole.

This is because typical screens can only display a tiny portion of the entire body at any one time. To get the "big picture" of a full-body view without sacrificing vital levels of detail, radiologists and pathologists will need a wide-screen, high-resolution display.

In fact, the work of postmortem pioneers and technology leaders may transform the autopsy suite of the future, all but replacing necropsy tables with imaging devices and a large, immersive screen that brings the work of radiology and imaging technologists into sharp relief.

Without question, invasive autopsies will remain the norm for at least the next few years. But postmortem radiology pioneers are convinced that the new procedure can help reduce the current reliance on time-consuming and potentially risky invasive techniques. The result could be more accurate conclusions, and a universal respect for the deeply held preferences of entire cultures and communities.

By Afshad Mistri
AuntMinnie.com contributing writer
May 15, 2006

Afshad Mistri is senior manager of advanced visualization at SGI. He has spent nearly two decades working on special projects aimed at revolutionizing computer graphics visualization.

Related Reading

Panoramic x-rays prove suitable for dental age calculation, October 12, 2005

CT helps unwrap mummy mystery, May 29, 2005

Radiologic 'autopsy' is already finding evidence without destroying it, December 4, 2003

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