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CT Scans: Again on the Cutting Edge

ER doctors can use it to pinpoint damage from gunshot, knife wounds, says study

TUESDAY, May 1 (HealthScout) -- CT scans may have another lifesaving use now that a Baltimore radiologist has discovered they can help emergency room doctors pinpoint the damage caused by guns and knives.

The technology could determine whether trauma patients really need abdominal surgery, and researchers say it could affect almost half of the patients who enter emergency rooms with violent wounds to their torsos.

Dr. Kathirkamanathan Shanmuganathan, an associate professor of radiology at the Maryland Shock Trauma Center in Baltimore, studied 95 men and nine women who were treated at the center for gunshot or knife wounds to the torso.

During the study, an exam and conventional X-rays sometimes showed no need for surgery, but a spiral CT scan found differently.

In 35 cases, the abdomen's membrane had been penetrated, and 22 of those patients went on to have surgery for the damage. The patients who had negative results were released from the hospital within 12 hours instead of having to stay for the standard three to five days of observation. None of the released patients returned to the center because any injuries had been missed, Shanmuganathan says.

Spiral CT scans -- the fastest kind available -- can not only identify which patients need surgery; they also provide better details on the exact nature of an injury, he says. Only 30 percent to 40 percent of those with gunshot wounds go directly to surgery because their situation is so dire, he explains. But almost 60 percent of these patients might only have local pain or internal injuries that can't be spotted right away. CT scans can help spot such serious conditions as peritonitis -- an inflammation of the stomach lining that can lead to infection.

"It's important only to operate when necessary," he says. "We're trying to select patients more carefully."

Shanmuganathan is presenting his findings today at the annual meeting of the American Roentgen Ray Society in Seattle.

One radiology expert thinks the study could change the treatment victims of gunshot or knife wounds.

"The premise sounds good," says Dr. Raleigh Johnson Jr., an associate professor and director of the radiological section and 3D imaging lab at the University of Texas Medical Branch. "It has the potential to change standard practice."

"There's no definite gold standard on how to evaluate them [victims of gunshot or knife wounds]," adds Shanmuganathan. "We decided to try the CT, which is very new."

Johnson did note one potential problem with the procedure: A bullet fragment lodged in the abdomen could create what is called a starburst effect, where the computer only sees the metal piece as a flash of white light. "It may obscure the picture," he explains.

Shanmuganathan agrees the starburst effect can be a problem, but he adds they toyed with the computer to get a clearer picture in those cases. And there are often other medical clues about where the bullet is located.

"At least, it [the starburst] tells you where the bullet is," he says, and there's no problem if the bullet is located in fatty tissue and away from vital organs.

Another consideration is cost: A typical CT scan costs between $1,000 and $1,500, Johnson says. But that expense could be outweighed by the lowered cost of shorter hospital stays for those who have negative results, he adds.

Shanmuganathan estimated CT scans cost between $600 and $800, and he also noted the daily cost of a hospital bed is higher than a CT scan. As for insurance coverage of the procedure, he says they'll have to wait and see, but CT scans for wounds to the flank and back have been covered in the past.

"If the results are good, they might cover it," he says.

Invented in 1972, CT scans have become an important diagnostic tool in many medical fields, experts say. The computerized X-rays are used to detect brain trauma, heart disease and most recently, the beginnings of lung cancer. The machine, which is shaped like half of a donut, takes X-rays from many angles and then assembles a three-dimensional picture with the help of computer technology.

What To Do

For details on the technology, visit the CT Network.

For more information on how CT scans can help detect lung cancer, go to Cornell University.

Read these HealthScout stories for more on CT scans.

SOURCES: Interviews with Kathirkamanathan Shanmuganathan, M.D., associate professor, radiology, Maryland Shock Trauma Center, Baltimore; Raleigh Johnson Jr., M.D., associate professor and director, radiological section and 3D imaging lab, University of Texas Medical Branch, Galveston, Texas; April 30, 2001 American Roentgen Ray Society annual meeting presentation
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