The prevalence and patterns of intraluminal air in acute appendicitis at CT.

Department of Radiology and Biomedical Imaging, University of California San Francisco, Box 0628, M-372, 505 Parnassus Avenue, San Francisco, CA, 94143-0628, USA.
Emergency Radiology 09/2012; 20(1). DOI: 10.1007/s10140-012-1076-6
Source: PubMed

ABSTRACT The purpose of this study is to investigate if the presence and distribution of intraluminal air in the appendix contributes to the computed tomography (CT) diagnosis of appendicitis. We identified 100 consecutive patients (57 men and 43 women; mean age, 38) with CT prior to appendectomy for acute appendicitis over a 5-year period and a control group of 100 consecutive patients (29 men and 71 women; mean age, 39) who underwent CT for acute abdominal pain without appendicitis. Patients were scanned using multidetector row CT scanners at 1.25 or 5-mm slice thickness, peak tube voltage of 120 kVp, and milliamperse automatically adjusted to attain a noise index of 12. Ninety-two of 100 study patients and 95 of 100 controls received 150 mL intravenous contrast. Two independent readers noted the presence and distribution pattern of intraluminal air in the appendix, appendiceal diameter, wall hyperemia, wall thickening (>3 mm), and wall stratification and presence of any secondary signs of appendicitis including fat stranding and free fluid. Data were compared between groups using Fisher's exact test and Student's t test. Intraluminal air in the appendix was more common in control patients versus patients with appendicitis (66 of 100 versus 27 of 100, p < 0.001). No significant differences in the patterns of intraluminal air were found between cases and controls. Among appendicitis cases, there was no significant difference in mean appendiceal diameter (12.8 versus 12.0, p = 0.20) or number of CT signs of appendicitis (1.93 versus 1.86, p = 0.78) in cases with intraluminal air versus without. No case of appendicitis demonstrated intraluminal air without secondary signs of appendicitis. Although intraluminal air is sometimes assumed to exclude a diagnosis of appendicitis, it is actually a common finding seen in up to 27 % of cases at CT. The pattern of intraluminal air was not helpful in differentiating a normal appendix from appendicitis.

  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of the present study was to investigate the significance of appendicoliths as an exacerbating factor of acute appendicitis using multivariate analysis. A total of 254 patients with pathologically proved acute appendicitis were enrolled in this retrospective study (male, 51 %; mean age, 40.1 years; range, 15-91 years). Two radiologists performed a consensus evaluation of preoperative CT images for the presence of appendicoliths in consensus. When there were appendicoliths, they assessed the number and location of appendicoliths, and measured the longest diameter of the largest appendicolith. Pathological diagnosis was used for the reference standard. The relationships of appendicoliths to gangrenous appendicitis and to perforated appendicitis were each assessed with multiple logistic regression models, which were adjusted for demographic and clinical characteristics of patients. Significant relationships were identified between gangrenous appendicitis and the presence of appendicoliths (OR, 2.2; 95 % CI, 1.2-4.0), the largest appendicolith more than 5 mm in the longest (OR, 3.0; 95 % CI, 1.6-5.7), and location of an appendicolith at the root of the appendix (OR, 2.0; 95 % CI, 1.1-3.8). Among the CT characteristics, the location of an appendicolith at the root of the appendix only showed significant relationship with perforated appendicitis (OR, 4.5; 95 % CI, 1.4-15.4). Size of the largest appendicolith and location of appendicoliths at the root of the appendix are exacerbating factors of acute appendicitis.
    Emergency Radiology 11/2012;