Scans Find Urological Problems Other Tests Often Miss

A new procedure requiring one 15-minute scan with a modern computed tomography (CT) machine may be all it takes to find tiny cancers, stones and other problems in the kidneys, bladders and urinary tracts of high-risk patients — saving them from additional tests and the risks of delayed detection and treatment.

Called multi-detector CT urography, or MDCTU, the procedure uses modern CT machines found in many large hospitals. MDCTU can spot problems in the tiny vessels of the body's urine collection system, as well as detect bladder cancer, kidney and bladder stones, and kidney cysts and cancers.

Radiologists in the U-M Health System say that MDCTU is a better option for high-risk patients than the traditional intravenous pyelogram (IVP) or urography (IVU). Often performed on patients with symptoms such as blood in their urine or problems with urination, X-ray exams using IVP or IVU are far less accurate and have high rates of false-positive or false-negative results.

Richard Cohan and Elaine Caoili Photo: Martin Vloet

"Our experiences with MDCTU in patients with prior bladder and urinary tract cancers have convinced us that it is as good as IVP — and probably far better — for detecting all abnormalities of the urinary system," says Richard H. Cohan, M.D., a professor of radiology in the U-M Medical School.

"We're able to see tumors as small as two- to three-millimeters, in areas where other exams can't go, and we've been able to save patients the delay and aggravation of coming back for repeated diagnostic scans and procedures," adds Elaine Caoili (M.D. 1993), a clinical assistant professor of radiology.

Working closely with physicians in the Michigan Urology Center, U-M radiologists have spent four years perfecting MDCTU technology. With more than 1,000 patients scanned, they are one of the most experienced MDCTU teams in the nation. Through presentations at medical meetings, U-M radiologists are sharing their methods and encouraging colleagues to adopt the new technique, which they say is extremely sensitive, very accurate and relatively easy to learn.

MDCTU scans use super-fast helical CT scanners, which pass X-rays through the patient's body from many angles and collect them on the other side using multiple detectors surrounding the patient. During the scan, the path of the X-rays is slightly altered by a contrast dye given intravenously to the patient. The dye works its way through the bloodstream into the kidneys and urinary tract, allowing the CT scanner to make detailed images of the patient's entire urinary system in "slices" less than one millimeter thick. Computers combine them to make cross sections and three-dimensional images, which can be viewed in different ways to spot problems.

Says Caoili, "We hope that MDCTU will become the first and only imaging test used for evaluating high-risk patients with urinary system symptoms, and that it will soon allow patients everywhere to get accurate early diagnoses that might improve their clinical outcomes."

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Read an expanded version of the story:
www.med.umich.edu/opm/newspage/2003/ctscans.htm

More information on cancers of the kidney, bladder and urinary tract:
www.cancer.med.umich.edu/learn/leadis.htm