Sonographic evaluation of acute appendicitis and its complications

Abstract

Objectives: The objectives of the study were to evaluate various sonographic findings in patients with clinically suspected acute appendicitis and its complications; to follow up and confirm sonographic findings by histopathological examination following surgery; and to determine the role of color Doppler sonography in acute appendicitis.

Materials and Methods: One hundred patients clinically suspected to have acute appendicitis underwent ultrasound examination using high-resolution transducers; linear array transducers of 7.5–10 MHz and curvilinear transducer of 3.5–5 MHz. The presence of aperistaltic, noncompressible, blind-ended tubular structure with a diameter ≥6 mm in the right iliac fossa was the primary criterion for the diagnosis of acute appendicitis. Other findings such as the presence of appendicoliths, gas within the lumen of appendix, loculated collections, and appendicular phlegmon were also considered.

Results: Out of 100 cases recruited for the study, 95 cases underwent surgical intervention in the form of immediate appendicectomy (89 patients), interval appendicectomy (four patients), or drainage of abscess(two patients). On histopathological/surgical correlation, true positive was 85, false positive – 1, true negative – 6, and false negative – 3. The observed sensitivity, specificity, positive predictive value, and negative predictive value of ultrasonography (US) in the diagnosis of acute appendicitis were 96.5%, 85.7%, 98.8%, and 66.7%, respectively, with an overall accuracy of 95.7%. In our study, 75% patients of appendicitis showed hyperemic color Doppler flow. Furthermore, the use of color and power Doppler sonography was more helpful in those patients where it was difficult technically to visualize the entire appendix.

Conclusion: Grayscale US should be the first primary evaluation for patient suspicious of acute appendicitis, and color Doppler is an additional modality to increase sensitivity and more accuracy.