CT scan for suspected acute appendicitis

JCHIMP 2000-9666 Journal of Community Hospital Internal Medicine Perspectives Vol. 1, January 2012, pp. 1–2 sici xxx PUBMED Abbreviation David M. Widlus MD

*David M. Widlus, MD, Union Memorial Hospital, Department of Radiology, University of Maryland School of Medicine Baltimore MD USA

Union Memorial Hospital, Department of Radiology University of Maryland School of Medicine

Baltimore MD USA

Journal of Community Hospital Internal Medicine Perspectives INTERNAL IMAGES CT scan for suspected acute appendicitis David. M. Widlus@CT scan for suspected acute appendicitis <para>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 (<figureref linkend="F0003">Fig. 3</figureref>).</para> <para>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 (<figureref linkend="F0001">Figs. 1</figureref> and <figureref linkend="F0002">2</figureref>). 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.</para> <figure id="F0001" articleid="10926" productid="JCHIMP" doi="10.3402/jchimp.v1i4.10926-F0001" colorgraphics="no"> <title>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. References

Pickhardt PJ , Lawrence EM , Pooler BD , Bruce RJ. Diagnostic performance of multidetector computed tomography for suspected acute appendicitis. Ann Intern Med. 2011;154(12):789–96. Available from: http://www.annals.org/content/154/12/789.full.pdf+html