CT scan for suspected acute appendicitis

doi:10.3402/jchimp.v1i4.10926

INTERNAL IMAGES

CT scan for suspected acute appendicitis

David M. Widlus, MD*

Union Memorial Hospital, Department of Radiology, University of Maryland School of Medicine, Baltimore, MD, USA

Received: 17 October 2011; Revised: 17 November 2011; Accepted: 23 November 2011; Published: 26 January 2012

Citation: Journal of Community Hospital Internal Medicine Perspectives 2011, 1: 10926 - DOI: 10.3402/jchimp.v1i4.10926

Journal of Community Hospital Internal Medicine Perspectives 2011. © 2011 David M. Widlus. This is an Open Access article distributed under the terms of the Creative Commons Attribution-Noncommercial 3.0 Unported License (http://creativecommons.org/licenses/by-nc/3.0/), permitting all non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Appendicitis is common with a 7% lifetime risk for an individual in the United States. Mean age at diagnosis is 22 years old. While frequently clinically obvious, by 2006, more than 90% of patients diagnosed with appendicitis had a CT scan of the abdomen and pelvis performed. Use of CT scans has allowed a decrease in false-negative rate at appendectomy to under 10% from a rate of approximately 20% before routine use of CT scan. In addition, the rate of perforation has decreased from nearly 30% to under 15%. In the pediatric population, initial ultrasound is often recommended, with CT utilized if the sonogram is inconclusive (Fig. 3).

Findings at CT scan, which are suggestive or diagnostic of appendicitis, include: dilation of the appendix to more than 6 mm; thickening of the wall of the appendix; enhancement of the wall of the appendix, which can be homogeneous or heterogeneous, including the stratified appearance referred to as a target sign; peri-appendiceal inflammatory stranding; appendicolith; peri-appendiceal abscess (Figs. 1 and 2). A focal area with decreased enhancement has been shown to be a reliable sign of perforation. Sensitivity and specificity of diagnosis with CT scans are up to 98% for each. When appendicitis is not present, an alternative diagnosis can be suggested in up to 40% of cases.

Fig. 1. Axial CT scan shows an inflamed, thick-walled appendix with peri-appendiceal inflammatory stranding (arrow).

Fig. 2. Coronal view shows the thick-walled appendix with stranding (short arrows). An appendicolith is clearly seen (long arrow).

Fig. 3. Transvaginal sonogram in a 16-year-old patient shows a thick-walled appendix with lumen distended with fluid (long arrow). A normal right ovary is seen just anterior (short arrows).

Conflict of interest and funding

The author has not received any funding or benefits from industry or elsewhere to conduct this study.

CT scan for suspected acute appendicitis

Conflict of interest and funding

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