A cut above autopsy
Sectra's spectacular visualisation system cuts, slices, spins and enlarges images of the body without dissection, all at the touch and spin of the doctor's fingers.health and fitness Updated: Feb 19, 2012 00:34 IST
As any CSI fan would know, doing an autopsy is a messy way to spend your day. Pathologists spend hours crouched over corpses looking for clues to indicate the cause and manner of death. In looking for signs of injury and diseases both inside and out, the body is, to quote its harshest critics, "mutilated" before being sewn back. If clues are missed before the final dissection, they remain lost and the case remains unsolved.
Sectra's Visualisation Table is changing all of that. This virtual autopsy system cuts, slices, spins and enlarges images of the body at the touch and spin of your fingers, giving doctors glimpses of every tissue, organ, fluid and foreign object without a single cut. "Using a virtual knife, you can slice the body, remove layers of skin and muscle to look inside," says Dr Anders Persson, director of the Center for Medical Image Science and Visualisation at Linköping University, who created this table that looks like a large touch-sensitive LCD screen mounted on four legs. "And all this can be done with a wave of your fingers," he says.
And Dr Persson does it with the enviable deftness of a gamer. "The table uses real-time and stored images created using computed tomography (CT) scans - 25,000 slices across the body - done in less than 20 seconds," he explains. Since different tissues, bone, fluids and foreign objects have different densities, the scanner's ray absorption varies. The software assigns them a density value and an NVIDiA graphics card - the kind used for high-speed gaming - transforms the data into 3-D images.
"Air pockets are blue, soft tissues are beige, blood vessels as red and bone as white. Different types of injuries and trauma, such as drowning, strangulation and gunshot wounds are easier to identify through imaging than conventional scalpel autopsy," says Dr Persson.
For example, cases of strangulation without external marks or bruising show up in autopsy imaging. He shows an image with blue marking in the throat tissue. "The blue colour that you see is gas, which shows it's a strangulation. We gave it as evidence and it was accepted by the court." Says Persson.
Up next on display is the image of a man with a large knife stuck in his ribs. "Murder!" I say, eyes wide. "No, it's actually suicide. You'd be surprised at the number of people who choose to stab themselves to death," says Dr Persson.
The Swedish police are already using the virtual-autopsy system to detect hidden evidence, such as air pockets in the wrong place in the body or bone fractures in a burns victim. "The biggest plus is that the system creates a permanent 3-D record that can be studied, reviewed, archived and transferred easily. Investigators can revisit the case anytime and look at the images again and again," says Dr Persson.
Another obvious advantage is that virtual autopsy allows investigation without destroying the body, a procedure considered distasteful, invasive or offensive by some cultures and faiths. "Since autopsies are not always acceptable to people from the Muslim and Jewish faiths, the table drew a lot of interest at Arab Health medical congress in Dubai last month," says Lars Wettergren, global partner manager, Sectra Imtec AB.
The technology is also being used in medical colleges to teach human anatomy without the need for cadavers. In hospitals, it is used for pre-operative planning and clinical diagnosis. "It helps surgeons choose the best treatment method before making the first cut, especially in the fields of orthopaedics and sports medicine," says Dr Persson.
That apart, the table has made backbreaking medical education and forensics a lot more fun.