| Technique finds tiny cancers sooner, more accurately
Scan detects bladder, kidney and urinary tract problems often missed by other tests
A single 15-minute CT scan may be all it takes to find tiny cancers, stones and other problems in the kidneys, bladders and urinary tracts of high-risk patients – potentially saving them from many additional tests, and from delayed detection and treatment.
And the detailed imaging scan can be done using CT machines now found in many large hospitals.
U-M radiologists Elaine Caoili, M.D., and Richard H. Cohan, M.D., have found that a technique known as MDCTU can spot numerous problems in the tiny vessels of the body’s urine collection system, as well as detecting bladder cancer, kidney and bladder stones, and kidney cysts and cancers.
And, they have found that MDCTU may be a better and far more accurate option for high-risk patients than the traditional 30-minute X-ray exam that is often done on patients with symptoms such as blood in their urine or problems with urination.
That traditional exam finds the cause of symptoms less than 50 percent of the time. And the test has high false-positive and false-negative rates. This often means that high-risk patients either endure a series of tests and scans before getting a firm diagnosis, or get a false sense of security from a mistakenly "clean" report and only get diagnosed much later.
"Our experience to date with MDCTU in patients with prior bladder and urinary tract cancer has convinced us that it is as good as the traditional test – and probably far better – for detecting all abnormalities of the urinary system," says Cohan, a professor of radiology at the U-M Medical School.
"We’re able to see subtle tumors as small as 2 to 3 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 Caoili, a clinical assistant professor of radiology. "We hope our colleagues will adopt this technique for use in patients in whom they strongly suspect urinary abnormalities, such as those with prior cancer."
MDCTU scans can be done on 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 to the patient intravenously. The dye works its way through the bloodstream into the kidneys, where it is excreted as part of the urine into tiny vessels within the kidneys and then into the thin, 12-inch-long tubes called ureters that lead to the bladder.
The contrast dye allows the CT scanner to make detailed images of the patient’s entire urinary system, in "slices" less than a millimeter thick. Computers combine them to make cross-sections and three-dimensional images that can be looked at in different ways to spot problems such as cancer.
For now, the MDCTU test is available to patients being seen at the Michigan Urology Center who have a history of urinary problems. But the team hopes to improve it further to be used on patients having symptoms for the first time.
More than 91,000 Americans are diagnosed with urinary system cancers each year, according to the American Cancer Society, and 25,000 die of those cancers. Most of those diagnosed have bladder or kidney cancer, while a smaller number have cancer in one or both ureters.
Men are three times more likely than women to develop urinary system cancers. Smokers, people over age 60, and people exposed to certain industrial chemicals, are also far more likely to develop these cancers.
Contact: Cancer AnswerLine, 1-800-865-1125 |
