Use and Accuracy of Computed Tomography Scan in Diagnosing Perforated Appendicitis

Abstract

Perforated appendicitis has major implications on patient care. The ability of computed tomography (CT) scan to distinguish perforation in the absence of phlegmon or abscess is unknown. The purpose of this study is to assess the use and accuracy of CT scans in diagnosing perforated appendicitis without phlegmon or abscess. A retrospective chart review of 102 patients who underwent appendectomy from 2011 to 2013 was performed. Patient demographics and operative and postoperative course were recorded. Two radiologists were then blinded to operative findings and CTscans reread and results correlated. Findings on CTscan were also analyzed for correlation with perforation. Univariate and multivariate statistical analysis was performed. Of the 102 patients, 49 were perforated and 53 nonperforated. Analysis of patient populations demonstrated patients with perforation were significantly older (45 vs 34 years, P = 0.002), had longer operative times (132 vs 81 minutes, P = 0.001), and longer length of stay (8.2 vs 1.5 days, P < 0.001). Nineteen perforations (37%) were correctly diagnosed by CT scan. The sensitivity of CT scan to detect perforation was 38 per cent, specificity 96 per cent, and positive predictive value of 90 per cent. After multivariate analysis of significant variables, three were demonstrated to significantly correlate with presence of perforation: presence of extraluminal air (odds ratio [OR], 28.9; P = 0.02); presence of intraluminal fecalith (OR, 5.7; P = 0.03); and wall thickness greater than 3 mm (OR, 3.2; P = 0.02). CT scan has a low sensitivity for diagnosing perforated appendicitis without abscess or phlegmon. Presence of extraluminal air bubbles, increased wall thickness, and intra-luminal fecalith should increase suspicion for perforation and are highly correlated with outcomes after appendectomy.

Risk of appendiceal cancer in patients undergoing appendectomy for appendicitis in the era of increasing nonoperative management

“…The recommendations for the use of antibiotic treatment alone is limited to cases of acute uncomplicated appendicitis; diagnosis on the basis of imaging results, which are fallible. Verma et al found that computed tomography, the most common and gold‐standard imaging test, only had a 38% sensitivity for identification of perforation in the absence of phlegmon or abscess, and Leeuwenburgh et al showed that magnetic resonance imaging or ultrasound with conditional use of CT scan incorrectly identified perforated appendicitis as uncomplicated cases in up to half of the cases. The distinction between complicated and uncomplicated appendicitis is crucial, as prior studies have shown that the rates of appendiceal malignancy are much higher in complicated cases compared with uncomplicated appendicitis.…”

Predictors of Failed Laparoscopic Appendectomy in Perforated Appendicitis

“…While accuracy of simple appendicitis is high, CT is far from perfect when identifying perforation with a specificity of 38% [13]. In addition, there is a discordance between surgeons, radiologists, and pathologists regarding the classification of perforation, which has been reported as high a 11.6% [14].…”

Savings from reducing low-value general surgical interventions

“…Similarly, stopping CT for the diagnosis of appendicitis may result in incorrect or delayed treatment and subsequently patient harm. Although CT should be considered low value, it may well be that the expertise for accurate ultrasonography, which is heavily operator dependent, is not readily available (particularly out of hours).…”