Editing Appendicitis (section)

====Computed tomography====
[[File:CAT scan demonstrating acute appendicitis.jpg|thumb|A CT scan demonstrating acute appendicitis (note the appendix has a diameter of 17.1 mm and there is surrounding fat stranding)]]
[[File:X-ray showing fecalith which has caused appendicitis.jpg|thumb|A [[fecalith]] marked by the arrow that has resulted in acute appendicitis.]]

Where it is readily available, [[computed tomography]] (CT) has become frequently used, especially in people whose diagnosis is not obvious on history and physical examination. Although some concerns about interpretation are identified, a 2019 Cochrane review found that the sensitivity and specificity of CT for the diagnosis of acute appendicitis in adults was high.<ref>{{Cite journal|last1=Rud|first1=Bo|last2=Vejborg|first2=Thomas S.|last3=Rappeport|first3=Eli D.|last4=Reitsma|first4=Johannes B.|last5=Wille-Jørgensen|first5=Peer|date=19 November 2019|title=Computed tomography for diagnosis of acute appendicitis in adults|journal=The Cochrane Database of Systematic Reviews|volume=2019|issue=11|doi=10.1002/14651858.CD009977.pub2|issn=1469-493X|pmc=6953397|pmid=31743429}}</ref> Concerns about radiation tend to limit use of CT in pregnant women and in children, especially with the increasingly widespread usage of MRI.<ref>{{cite journal | vauthors = Kim Y, Kang G, Moon SB | title = Increasing utilization of abdominal CT in the Emergency Department of a secondary care center: does it produce better outcomes in caring for pediatric surgical patients? | journal = Annals of Surgical Treatment and Research | volume = 87 | issue = 5 | pages = 239–244 | date = November 2014 | pmid = 25368849 | pmc = 4217253 | doi = 10.4174/astr.2014.87.5.239 }}</ref><ref>{{cite journal | vauthors = Liu B, Ramalho M, AlObaidy M, Busireddy KK, Altun E, Kalubowila J, Semelka RC | title = Gastrointestinal imaging-practical magnetic resonance imaging approach | journal = World Journal of Radiology | volume = 6 | issue = 8 | pages = 544–566 | date = August 2014 | pmid = 25170393 | pmc = 4147436 | doi = 10.4329/wjr.v6.i8.544 | doi-access = free }}</ref>

The accurate diagnosis of appendicitis is multi-tiered, with the size of the appendix having the strongest [[positive predictive value]], while indirect features can either increase or decrease sensitivity and specificity. A size of over 6&nbsp;mm is both 95% sensitive and specific for appendicitis.<ref>{{cite journal | vauthors = Garcia K, Hernanz-Schulman M, Bennett DL, Morrow SE, Yu C, Kan JH | title = Suspected appendicitis in children: diagnostic importance of normal abdominopelvic CT findings with nonvisualized appendix | journal = Radiology | volume = 250 | issue = 2 | pages = 531–537 | date = February 2009 | pmid = 19188320 | doi = 10.1148/radiol.2502080624 | doi-access =  }}</ref>

However, because the appendix can be filled with fecal material, causing intraluminal distention, this criterion has shown limited utility in more recent meta-analyses.<ref name="plumpy1">{{cite journal | vauthors = Doria AS, Moineddin R, Kellenberger CJ, Epelman M, Beyene J, Schuh S, Babyn PS, Dick PT | title = US or CT for Diagnosis of Appendicitis in Children and Adults? A Meta-Analysis | journal = Radiology | volume = 241 | issue = 1 | pages = 83–94 | date = October 2006 | pmid = 16928974 | doi = 10.1148/radiol.2411050913 }}</ref> This is as opposed to ultrasound, in which the wall of the appendix can be more easily distinguished from intraluminal feces. In such scenarios, ancillary features such as increased wall enhancement as compared to adjacent bowel and inflammation of the surrounding fat, or fat stranding, can be supportive of the diagnosis. However, their absence does not preclude it. In severe cases with perforation, an adjacent [[phlegmon]] or [[abscess]] can be seen. Dense fluid layering in the pelvis can also result, related to either [[pus]] or [[feces|enteric spillage]]. When patients are thin or younger, the relative absence of fat can make the appendix and surrounding fat stranding difficult to see.<ref name="plumpy1"/>