Imaging trends for appendicitis probed

August 1, 2012

A retrospective review of children evaluated for appendicitis in emergency departments between 2005 and 2009 found that the use of ultrasound has risen whereas the use of computed tomography has decreased.

A retrospective review of children evaluated for appendicitis in emergency departments (EDs) between 2005 and 2009 found that the use of ultrasound has risen whereas the use of computed tomography (CT) has decreased, although major pediatric institutions vary greatly in their use of these imaging techniques. In addition, the review determined that increased use of ultrasound or combined ultrasound and CT is associated with a lower rate of negative appendectomy (normal appendix at surgery) than with use of CT alone.

Data were drawn from nearly 9 million ED visits at 40 pediatric institutions at which 55,238 cases of appendicitis were identified. A median 34% of patients with appendicitis underwent CT compared with 6% who had ultrasound. Overall, 48% of those with appendicitis underwent either of these imaging modalities; 2% had both. Of patients with appendicitis, those who were girls and aged younger than 5 years were most likely to be imaged, whether by ultrasound or CT. Computed tomography use decreased 6% from 2007 (when it peaked) to 2009 for appendicitis cases, and ultrasound use increased 7.7% from 2005 to 2009.

Investigators found no association between the rate of hospital-level imaging and 2 important clinical outcomes: the rate of return visits requiring admission and the perforation rate (Bachur RG, et al. J Pediatr. 2012;160[6]:1034-1038).

Ultrasound and abdominal CT have fairly good sensitivity and specificity for appendicitis. Ultrasound has the disadvantage of being more operator dependent; CT scan the disadvantage of radiation exposure. The importance of that radiation exposure was highlighted by a recent, well-publicized, retrospective cohort study. Researchers estimated that 1 excess case of leukemia and 1 excess brain tumor occur every 10 years for every 10,000 head CTs obtained in children aged younger than 10 years (Pearce MS, et al. Lancet. 2012. Epub ahead of print). Physician and parent awareness of that study may accelerate the decreased use of CT for evaluation of abdominal pain.
-Michael Burke, MD