Comparative study of imaging features in uncomplicated and complicated acute appendicitis.

Background: Acute appendicitis is a common cause of acute abdominal pain necessitating surgical intervention. While the traditional treatment has been urgent appendectomy, recent studies suggest that an antibiotics-first approach can be safe for uncomplicated cases. Classifying appendicitis into uncomplicated and complicated categories is crucial for guiding treatment decisions and predicting patient outcomes. This study aims to evaluate the distinct imaging findings associated with uncomplicated appendicitis and its complicated subtypes-phlegmonous, gangrenous, and perforated appendicitis-to aid in differential diagnosis.

Methods: This retrospective observational study was conducted from January 2014 to December 2023 and included 1,250 patients (492 women, 758 men) who underwent an appendectomy with available pathology results. After excluding 56 patients with normal pathology, 52 with non-appendicitis pathologies, and 48 with inaccessible computed tomography (CT) images, 1,094 patients were analyzed. CT images were evaluated for appendiceal diameter, wall thickness, cecal wall thickness, periappendiceal fat stranding, effusion, lymphadenopathy, intraluminal and free periappendiceal air, mucosal hyperenhancement, and the presence of appendicolith.

Results: The diameter of the appendix, along with the presence of periappendiceal air, effusion, and intraluminal appendicolith, were significantly higher in the perforated appendicitis group compared to other groups (p<0.05). Periappendiceal fat stranding, evaluated as a binary variable, did not show significant differences among the groups. Appendiceal wall thickness was higher in the perforated group and lower in the non-perforated gangrenous group compared to the uncomplicated group (p<0.05). No significant correlation was found for mucosal hyperenhancement between the appendicitis subgroups. Intraluminal air, though normal in a healthy appendix, was a specific predictor of complicated appendicitis when combined with other findings.

Conclusion: This study provides a detailed analysis of distinct imaging findings associated with uncomplicated and complicated appendicitis. Key differentiators such as appendiceal diameter, periappendiceal air, effusion, and intraluminal appendicolith are crucial for accurate diagnosis. The findings highlight the importance of these parameters in distinguishing various types of appendicitis, offering valuable insights for clinical practice. Future prospective studies and advanced imaging techniques are needed to validate these findings and enhance the diagnosis and management of acute appendicitis and its complications.