Systematic Review and Meta-Analysis of CT Features for Differentiating Complicated and Uncomplicated Appendicitis

Abstract

Purpose To perform a systematic review and meta-analysis to identify computed tomographic (CT) features for differentiating complicated appendicitis in patients suspected of having appendicitis and to summarize their diagnostic accuracy. Materials and Methods Studies on diagnostic accuracy of CT features for differentiating complicated appendicitis (perforated or gangrenous appendicitis) in patients suspected of having appendicitis were searched in Ovid-MEDLINE, EMBASE, and the Cochrane Library. Overlapping descriptors used in different studies to denote the same image finding were subsumed under a single CT feature. Pooled diagnostic accuracy of the CT features was calculated by using a bivariate random effects model. CT features with pooled diagnostic odds ratios with 95% confidence intervals not including 1 were considered as informative. Results Twenty-three studies were included, and 184 overlapping descriptors for various CT findings were subsumed under 14 features. Of these, 10 features were informative for complicated appendicitis. There was a general tendency for these features to show relatively high specificity but low sensitivity. Extraluminal appendicolith, abscess, appendiceal wall enhancement defect, extraluminal air, ileus, periappendiceal fluid collection, ascites, intraluminal air, and intraluminal appendicolith showed pooled specificity greater than 70% (range, 74%-100%), but sensitivity was limited (range, 14%-59%). Periappendiceal fat stranding was the only feature that showed high sensitivity (94%; 95% confidence interval: 86%, 98%) but low specificity (40%; 95% confidence interval, 23%, 60%). Conclusion Ten informative CT features for differentiating complicated appendicitis were identified in this study, nine of which showed high specificity, but low sensitivity. RSNA, 2017 Online supplemental material is available for this article.

Appendiceal neoplasm risk associated with complicated acute appendicitis—a population based study

“…Differential diagnosis between these two forms acute appendicitis without imaging is not feasible [35]. There is a need for determining CT criteria that could help reliably identify complicated acute appendicitis [4] and also incidental appendiceal neoplasms to ensure their surgical resection [36]. Several CT features suggestive of coexisting appendiceal tumor have been described, but frequently, the radiographic appearance is one of acute appendicitis [36][37][38].…”

“…In order to optimize and tailor the treatment for acute appendicitis, precise and accurate diagnostic tools, such as computed tomography (CT) are required. As CT has high sensitivity in diagnosing acute appendicitis, it has become the golden standard in right lower quadrant abdominal pain differential diagnosis [4]. Uncomplicated acute appendicitis may also resolve spontaneously without even antibiotics, let alone surgery [5].…”

Reliability of Standardized Reporting System of acute appendicitis in adults at low-dose 320-rows CT

“…In this study, there is excellent inter-observer agreement of peri-appendicular fat stranding, uid collection and focal cecal thickening. Phlegmon was de ned as diffuse and substantial in ammation of the periappendiceal fat with ill-de ned but not rim-enhancing uid collections and abscess is de ned as a discrete collection with rim enhancement (15)(16)(17). Another study added that peri-appendiceal uid collection revealed area under the curve of 0.80, sensitivity of 77%, and accuracy of 80% and the highest speci city (100%) is recorded for the presence of extraluminal air and a perityphlitic abscess (27).…”

“…Another study added that peri-appendiceal uid collection revealed area under the curve of 0.80, sensitivity of 77%, and accuracy of 80% and the highest speci city (100%) is recorded for the presence of extraluminal air and a perityphlitic abscess (27). Another study added that the peri-appendiceal fat stranding is the only feature with high sensitivity (94%) for diagnosis of acute appendicitis (17). Previous studies reported that presence of gas in the surrounding peri-appendicular tissue is sign of acute appendicitis.…”

“…Computed tomography (CT) has a signi cant role in diagnosis of acute appendicitis as it provides comprehensive information about the appendix, and peril-appendicular changes (15)(16)(17)(18). In most cases, CT simultaneously shows multiple ndings, enabling con dent diagnosis of appendicitis.…”