Doptaus--a simple criterion for improving sonographic diagnosis of acute appendicitis

To determine the efficacy of 'Detection Of Pin-point Tenderness on the Appendix on abdominal UltraSound' (DOPTAUS) for improving sonographic diagnosis by junior and senior ultrasound operators.

An analytical study was done at the Radiology Department, Dow University of Health Sciences and Civil Hospital Karachi from March 2005 to December 2006. Adult patients of either gender with clinically suspected acute appendicitis referred to the department during regular working hours and later operated in the same hospital were included. Each patient was scanned by a junior and a senior ultrasound operator using the conventional criteria first and later focused ultrasound of the point of maximal tenderness (DOPTAUS). Diagnosis was compared against surgical findings for accuracy determination. Percentage agreement between the operator groups was evaluated by kappa (k) statistics.

Out of the referred 100 patients (58 males, 42 females, mean age 32.6 +/- 7.8 years), appendicitis was diagnosed using conventional criteria by juniors in 48 and by seniors in 74 patients (k = 0.4, sensitivity = 56.74%, specificity 53.3%). Using DOPTAUS acute appendicitis was diagnosed in 69 by juniors and 85 by seniors (k = 0.69, sensitivity = 90.4%, specificity = 83.33%). On surgery, 94 cases were found to have acute appendicitis.

In this series, focused ultrasound after detecting maximal pin-point tenderness resulted in improved diagnosis of acute appendicitis in clinically suspected cases. Moreover, the percentage agreement between the operator groups increased from intermediate to good with improved accuracy. This shows that less experienced operators can improve their diagnostic accuracy of acute appendicitis using focal pin-point tenderness as the guide.