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Medicine Science Technology

The Virtues of the Virtual Autopsy 48

Hugh Pickens writes "Maryn McKenna writes in Scientific American that the standard autopsy is becoming increasingly rare for cost reasons, religious objections, and because autopsies reveal medical mistakes, making doctors and hospitals uncomfortable. Researchers in several countries have been exploring the possibility that medical imaging might substitute a 'virtual autopsy' for the more traditional variety. 'So few autopsies are being done now that many medical students get out of school never having seen one,' says Gregory Davis. 'And yet in medicine, autopsy is the most powerful quality-control technique that we have and the reason we know as much as we do about many diseases and injuries.' The process, dubbed 'virtopsy,' combines MRI and CT scanning with computer-aided 3-D reconstruction to prove causes of death for difficult cases, which included drownings, flaming car crashes, and severe injuries to the skull and face. Since 2004 the U.S. military has performed x-rays and CT scans on the bodies of every service member killed where the armed forces have exclusive jurisdiction — that is, not just on battlefields abroad but on U.S. bases as well. 'It allows us to identify any foreign bodies present, such as projectiles,' says Edward Mazuchowski. 'X-rays give you the edge detail of radio-opaque or metallic objects, so you can sort out what the object might be, and CT, because it is three-dimensional, shows you where the object is in the body.' A study conducted among intensive care unit patients in Germany compared diagnoses made before death with the results of both traditional and virtual autopsy in 47 patients and with only virtual autopsy in another 115 whose families refused standard autopsy. Virtual autopsies confirmed 88 percent of diagnoses made before death, not far behind the 93 percent rate for traditional postmortem exams. 'The findings so far are mixed,' says Elizabeth Burton of Johns Hopkins University. Virtual autopsy, she says, 'is better for examining trauma, for wartime injuries, for structural defects. But when you start getting into tumors, infections and chronic conditions, it's not as good, and I doubt it will ever be better.'"
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The Virtues of the Virtual Autopsy

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  • Re:safe dose (Score:2, Informative)

    by Anonymous Coward on Tuesday October 23, 2012 @06:58PM (#41746275)

    Potentially by a significant margin. In practice, most of the equipment is tuned to specific requirements of resolution, etc. Some flexibility is possible, for example, the use of mammography film/sensors for x-raying limbs for forensic purposes (usually child abuse cases). Mammography films/sensors have very low sensitivity but exceptional resolution and very high contrast; however, the full benefit cannot be obtained as a micro focus mammography x-ray source has insufficient energy to penetrate bone, so a conventional x-ray source with poorer focus must be used.

    CT has greater scope for improving the images quality, because CT image noise limited by photon shot noise in order to keep doses down. With modern scanners, they typically scan at maximum resolution always, but can then resample the images to lower resolution if desired for viewing (usually to reduce noise, or in my hospital's case because their SAN contract means archiving the full resolution data is cost-prohibitive). The technologist instead of controlling scanner parameters directly, merely specifies the desired quantity of noise at a standard resolution.

    From a medical perspective, this doesn't actually give much benefit in terms of diagnostic performance. From a practical perspective there are other issues as technologists are often barely trained. I once asked a CT technologist to scan a dry skull for use as an anatomical teaching tool, and asked them to crank up everything on the scanner to maximum; they couldn't do it even when I told them exactly what settings to change. As another example, I was looking at the functionality available on the scanner, which used a "tab page" control for the scan parameters and when I finished, I left the 2nd page visited rather than the first; I got my ass chewed out for that because the technologist couldn't work out what had happened to the scan settings, necessitating delaying an emergency scan and prompting an emergency support call to the scanner manufacturer.

  • Re:Wait (Score:5, Informative)

    by ShmuelP ( 5675 ) on Tuesday October 23, 2012 @09:16PM (#41747179)

    What also makes me uncomfortable is seeing something as retarded as "religious objections" as a growing reason for not doing an autopsy. In the Middle Ages, scientists had to buy bodies illegally to make their studies, risking to be burned at the stake for that "horrible crime". Haven't people learned anything yet? What the fuck does their god of choice care if someone cuts open a dead body? He refuses to welcome the deceased guy in Heaven, or Valhalla or whatever?

    Western civilization has a notion called "religious freedom". We've discovered that things are much more peaceful if we ensure that everyone can practice as they see fit, regardless of how wrong we their religious beliefs (or lack thereof) may be. (Exceptions to the above when said practices involve harm to others.) So if my religion doesn't allow for routine autopsies, for whatever reason that you clearly don't understand, how about leaving it alone? You may feel free to instruct your heirs to handle your remains as you see fit, and the rest of us might appreciate the same courtesy in return.

In less than a century, computers will be making substantial progress on ... the overriding problem of war and peace. -- James Slagle