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

Objective: 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. Methods: 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. Results: 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. Conclusion: 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 (JPMA 59:79; 2009). is that the point of maximum tenderness is identified by the patient and a focused ultrasound of that particular spot is done instead of concentrating on the right iliac fossa or doing a whole abdomen scan. Using this simple innovation, this study was planned to determine the improvement in the ultrasound diagnosis of acute appendicitis among senior as well as junior radiologists and residents at the radiology department of a public sector hospital. Patients and Methods The study was conducted at the department of radiology, Dow University of Health Sciences and Civil Hospital, Karachi from March 2005 to December 2006. The inclusion criteria for the patients were adults of either gender referred to the department through emergency with suspected acute appendicitis for diagnostic ultrasound of abdomen or right iliac fossa. All of the cases were referred during regular working hours. Patients with palpable lump, chronic or repeated episodes of pain and those scanned in emergency after regular working hours and operated without or re-scan by seniors were excluded. Those patients whose follow up was not available, were also excluded. All the included subjects were scanned on Toshiba Nemio with 3.55 MHz probe first by a junior and then by senior operators. The former were defined for the purpose of study as third or fourth year radiology residents or medical officers with postgraduate qualification and experience of two years or less. The non-qualified medical officers not enrolled in a training program and the residents in first two years of training were not considered. Senior operators were defined as faculty members or medical officers with post-graduate qualification in radiology and post-qualification experience of more than two years. Ultrasound was performed fist using conventional ultrasound criteria14 and then focused scan after the patient pinpointed the site of maximum tenderness as reported by Soda et al.11,16 The findings were recorded by an independent observer. Final report was issued based on the seniors' findings. Patients were followed till their operation and surgical findings were taken as the gold standard for accuracy determination i.e. sensitivity, specificity and predictive values. Kappa (K) statistics were applied for comparison between the operator groups to determine agreement. K value of 0.8 was taken as excellent, 0.4-0.79 as intermediate to good, and less than 0.4-0 as poor to no agreement.