Reported December 2006

BACKGROUND: A new study from the University of North Carolina Hospitals in Chapel Hill shows MRI is both safe and accurate for diagnosing pregnant women with acute pain in the abdomen and pelvis, surpassing the limits of both CT scans and ultrasound for this purpose. The researchers analyzed the MRIs of 29 pregnant patients who had been experiencing acute abdominal pain, and correctly diagnosed the cause of that pain in 28 of those cases. Some of the problems doctors can diagnose include appendicitis, fibroids, ovarian cysts, kidney stones, gall bladder problems, and problems with the fetus itself.

A NEW ALTERNATIVE: It can be difficult to diagnose acute abdominal pain in pregnant women because the enlarged uterus pushes organs out of their normal locations, so the pain is not in the usual place. There are also more possible causes for pain,. Today, CT scanning is normally used for diagnosing abdominal pain, but there is a risk of exposing the fetus to harmful ionizing radiation, increasing cancer risks in both fetus and mother. Ultrasound (sonography) doesn't use radiation, but its imaging potential is limiting. MRI is becoming a desirable option as the medical community and the public becomes more aware of the risks associated with radiation, particularly for pregnant women. The latest generation of MRI scanners has reduced the time needed to image a patient, so it is becoming possible to see what is actually happening inside the abdomen or pelvis.

ABOUT CAT SCANS: CAT (Computerized Axial Tomography) scans are similar to conventional X-ray imaging, but instead of imaging the outline of bones and organs, a CAT scan machine forms a full 3-D computer model of the inside of a patient's body. Doctors can even examine the body one narrow slice at a time. The X-ray beam moves all around the patient, scanning from hundreds of different angles, and the computer takes all that information to compile a 3-D image of the body.

HOW MRI WORKS: Magnetic resonance imaging uses radiofrequency waves and a strong magnetic field instead of X-rays to provide clear and detailed pictures of internal organs and tissues. These radio waves are directed at protons in hydrogen atoms -- one of the most abundant atoms in the human body, because of the body's high water content. The waves "excite" the protons, and when they "relax," they emit strong radio signals. A computer can turn those signals into a high-contrast image showing differences in the water content and distribution in various bodily tissues. It is becoming increasingly popular as an alternative to traditional X-ray mammography for the early diagnosis of breast cancer because women aren't exposed to the same radiation they experience with X-rays.

The American Association of Physicists in Medicine contributed to the information contained in the TV portion of this report.

If you would like more information, please contact:

University of Pittsburgh Medical Center
Pittsburgh, PA
(412) 647-UPMC (8762)
(800) 533-UPMC (8762)
upmcweb@upmc.edu

Ben Stein
American Institute of Physics
for the American Association of Physicists in Medicine
(301) 209-3088
bstein@aip.org

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Magee-Womens Hospital, University of Pittsburgh Medical Center