MRI Effective Alternative for Diagnosing Pediatric Appendicitis

Magnetic resonance imaging without contrast is a viable alternative test for suspected pediatric appendicitis, according to a study in the journal Radiology.

Researchers from the Texas Children’s Hospital in Houston performed a study of 81 patients (34 male, 47 female) to prospectively compare MR imaging without contrast and ultrasound for diagnosis of pediatric appendicitis. The mean age was 12.3 years. Traditionally, if ultrasound is inconclusive, ultrasound followed by CT scan is used for diagnosis. However, ultrasounds are not always available and CT scans increase the patients’ overall exposure to radiation.

All patients underwent an ultrasound of the right lower quadrant, as well as a nonenhanced nonsedated abdominopelvic MR imaging exam. Two pediatric radiologists who were blinded to the ultrasound findings reviewed the MR images.

When equivocal interpretations were designated positive, sensitivity was 93.3 percent for MR imaging and 90.0 percent for ultrasound.  The specificity was 98 percent for MR imaging and 86.3 percent for ultrasound. Positive predictive value was 96.5 percent for MR imaging and 79.4 percent for ultrasound; and negative predictive value was 96.2 percent for MR imaging and 93.6 percent for ultrasound.

When equivocal interpretations were designated negative, MR imaging sensitivity, specificity, positive predictive value and negative predictive value were unchanged. For ultrasound, sensitivity was 86.7 percent; specificity was 100 percent; positive predictive value was 100 percent; and negative predictive value was 92.7 percent.

The authors concluded that nonenhanced MR imaging demonstrated high diagnostic performance that was similar to that of ultrasound in the pediatric population.