Role of ultrasound in the diagnosis of acute appendicitis: A prospective study

Abstract

Background and Aim: Although the clinical presentation of acute appendicitis is typical in 70% of the cases, about 30%of the patients have an uncertain pre-operative diagnosis. Consequently the rate of unnecessary laparotomy is as high as 20-25%. The aim of the study was, to evaluate the role of ultrasound in the diagnosis of acute appendicitis in clinically equivocal cases. Materials and Methods: 100 patients clinically suspected to be acute appendicitis were referred for ultrasound examination. Presence of appendicoliths, loculated collections, complex masses in the right iliac fossa were also considered in the diagnosis of acute appendicitis. The sonological findings were correlated with surgical findings. In patients, who had negative graded compression US examination, abdomen and pelvis were assessed with curvilinear transducer of 3.5-7.0MHz Results: Of the 100 patients who formed the study population, 76 patients had acute appendicitis. Ultrasound was sensitive in detecting acute appendicitis in 66 patients. 10 patients were falsely diagnosed as acute appendicitis on ultrasound. One patient was false positively diagnosed as having acute appendicitis. US could detect normal appendix in 8 cases. Ultrasound provided alternate diagnosis in 6 patients, thus influencing the management. The overall accuracy of ultrasound in the diagnosis of acute appendicitis was 86.36%. The sensitivity, specificity, predictive value of a positive test and predictive value of a negative test were 86.64%, 83.33%, 97.05% and 50% respectively. Conclusion: Ultrasound being non-invasive, non-traumatic, readily available modality is a result-oriented examination in clinically equivocal cases of acute appendicitis.