MRI Technique of Choice to Evaluate Pregnant Patients with Possible Appendicitis

Magnetic resonance imaging (MRI) provides physicians with a safe and accurate tool for the diagnosis of appendicitis in pregnant patients without the increased risks of radiation to the patient and fetus, according to new findings.

"Appendicitis is the most common cause of right lower quadrant pain in the pregnant patient that requires emergent surgical intervention. It occurs in approximately one in 1,500 pregnancies,” said Chris Ho, M.D., from the University of Virginia (Charlottesville, VA, USA), and lead author of the study.

Researchers performed an analysis of 16 patients and evaluated studies performed specifically for pregnant patients with right lower quadrant pain over a two-year period at their institution. "Approximately 33% of the examinations were positive or highly suggestive of appendicitis. Of those positive studies, 80% were confirmed at surgery and pathology to have acute appendicitis. Over this period we were approximately 94% accurate in correctly diagnosing the presence or absence of appendicitis using MRI,” said Dr. Ho.

"A pregnant uterus can hamper a physician's physical examination as the appendix can move into uncommon locations as pregnancy progresses, making the diagnosis of ‘classic' appendicitis difficult. Consequently, imaging plays an important role in the diagnosis,” said Dr. Ho. "CT [computed tomography] has been shown to be very accurate in the diagnosis of appendicitis, but many consider the radiation risk to the fetus to outweigh the benefit of the scan. Ultrasound carries no radiation risk, but imaging the appendix is often unsuccessful in the nonpregnant patient and even more difficult in the pregnant patient,” he said.

This study's findings were presented at the 2009 American Roentgen Ray Society (ARRS) annual meeting in Boston, MA, USA, April 26-30, 2009.

"The biggest advantage of using MR is the lack of radiation exposure to both the mother and fetus. We feel that, given its advantages, MRI will become the diagnostic imaging study of choice in the pregnant patient with suspected appendicitis,” concluded Dr. Ho.

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