Study finds ways to improve detection of blood clots i...( gative chest CT result did not confiden...),Health

"This study suggests that chest CT angiogram for detecting dangerous blood clots in the lung is good, but sometimes it is not enough," noted Paul D. Stein, MD, director of research education at St. Joseph Mercy Oakland Hospital in Pontiac, Michigan, professor of medicine at Wayne State University, and lead author of the paper. "We can more accurately detect or rule out pulmonary embolism by taking pictures of the leg veins in addition to pictures of the lung arteries."

The results of the chest CT combined with the patient's clinical probability assessment were comparable to the results from the combined chest CT and leg CT scans.

"Our study spells out the strengths and weaknesses of chest CTs for diagnosing pulmonary embolism, and will help guide physicians on when more tests are needed," added Stein, who also chaired the PIOPED II steering committee.

During a chest CT angiogram, contrast material (dye) to make the blood vessels in the lungs more visible is injected into a vein in the patient's arm. The patient lies on a table as a machine with dozens of detectors rotates around to quickly take X-ray pictures of the blood vessels -- in the lungs for the chest CT or in the pelvis or thighs for the leg CT. No additional dye is needed for the leg CT, which can be performed immediately after the chest CT. A computer combines the images to make detailed pictures.

CT scans are noninvasive and well tolerated by most patients. Adverse effects are rare and are primarily related to the iodine-based dye that is injected; possible complications include kidney damage in patients with kidney disease and allergic reaction. The tests involve some exposure to radiation, but the benefits outweigh the risks.

Risk factors for pulmonary embolism include blood clots in the leg or a history of such problems, and certain inherited conditions th
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31-May-2006