Appendiceal ultrasonography performed by nonradiologists: does it help in the diagnostic process?

We performed a retrospective study to compare the sensitivity, specificity, predictive value, and diagnostic accuracy of appendiceal ultrasonography performed by unsupervised technicians during the nighttime hours with studies performed during the day by supervised technicians. Fifty-nine percent of the 163 sonographic examinations were done during the day, and 41% were performed at night. The sensitivity during the day (61%) was significantly higher than at night (26%), as was the positive predictive value (93% day, 71% night). We conclude that ultrasonography is an operator-dependent study. Its sensitivity is so diminished when not performed by an experienced radiologist or technician that a negative examination is not reliable.