IS Case 76: Acute Appendicitis
Imaging Sciences URMC
Publication Date: 2009-05-19
Acute appendicitis is the result of luminal obstruction and subsequent bacterial overgrowth with infection. Clinical signs include periumbilical pain migrating to the right lower quadrant and/or focal tenderness at McBurney point.
Upon imaging, a dilated appendix of > 0.7 cm has a high sensitivity for acute appendicitis (> 90%). As in this case, accompanying findings include an enhancing, thickened appendiceal wall, appendicolith(s), cecal tip wall thickening and surrounding inflammatory changes. Of note, a normal, gas or contrast-filled appendix may measure up to 1.0 cm without accompanying findings to suggest acute appendicitis. Contrastingly, a 6.0 mm appendix may have several accompanying signs to make the diagnosis. With the advent of multi-detector CT, coronal reformats have become useful for confirming the diagnosis.
In young, thin people, particularly women of child-bearing age and children, ultrasound is an efficacious first line test as it spares the radiation dose and has demonstrated acceptable sensitivity and specificity (85% and 90% respectively). Unfortunately, its use has declined over the past decade.
- Jeffrey RB. Appendicitis. 9/21/2006. https://my.statdx.com.
- Paulson EK, Harris JP, Jaffe TA, Haugan PA, Nelson RC. Acute appendicitis: added diagnostic value of coronal reformations from isotropic voxels at multi-detector row CT. Radiology. 2005 Jun;235(3):879-85. [PMID: 15833993]