Editing Appendicitis (section)

===Imaging===
In children, the clinical examination is important to determine which children with abdominal pain should receive immediate surgical consultation and which should receive diagnostic imaging.<ref name="pmid17652298">{{cite journal | vauthors = Bundy DG, Byerley JS, Liles EA, Perrin EM, Katznelson J, Rice HE | title = Does this child have appendicitis? | journal = JAMA | volume = 298 | issue = 4 | pages = 438–451 | date = July 2007 | pmid = 17652298 | pmc = 2703737 | doi = 10.1001/jama.298.4.438 | author-link2 = Julie Story Byerley }}</ref> Because of the health risks of exposing children to radiation, ultrasound is the preferred first choice with CT scan being a legitimate follow-up if the ultrasound is inconclusive.<ref name="ACRfive">{{Citation |author1 = American College of Radiology |author1-link = American College of Radiology |title = Five Things Physicians and Patients Should Question |publisher = [[American College of Radiology]] |work = Choosing Wisely: an initiative of the [[ABIM Foundation]] |url = http://choosingwisely.org/wp-content/uploads/2012/04/5things_12_factsheet_Amer_Coll_Radiology.pdf |access-date = August 17, 2012 |url-status = live |archive-url = https://web.archive.org/web/20120416220509/http://choosingwisely.org/wp-content/uploads/2012/04/5things_12_factsheet_Amer_Coll_Radiology.pdf |archive-date = April 16, 2012 }}</ref><ref name="effectiveusct">{{cite journal | vauthors = Krishnamoorthi R, Ramarajan N, Wang NE, Newman B, Rubesova E, Mueller CM, Barth RA | title = Effectiveness of a staged US and CT protocol for the diagnosis of pediatric appendicitis: reducing radiation exposure in the age of ALARA | journal = Radiology | volume = 259 | issue = 1 | pages = 231–239 | date = April 2011 | pmid = 21324843 | doi = 10.1148/radiol.10100984 | doi-access =  }}</ref><ref name="appendicitischildren">{{cite journal | vauthors = Wan MJ, Krahn M, Ungar WJ, Caku E, Sung L, Medina LS, Doria AS | title = Acute appendicitis in young children: cost-effectiveness of US versus CT in diagnosis – a Markov decision analytic model | journal = Radiology | volume = 250 | issue = 2 | pages = 378–386 | date = February 2009 | pmid = 19098225 | doi = 10.1148/radiol.2502080100 | doi-access =  }}</ref> CT scan is more accurate than ultrasound for the diagnosis of appendicitis in adults and adolescents. CT scan has a [[sensitivity (tests)|sensitivity]] of 94%, [[Specificity (tests)|specificity]] of 95%. Ultrasonography had an overall [[sensitivity (tests)|sensitivity]] of 86%, a [[Specificity (tests)|specificity]] of 81%.<ref>{{cite journal | vauthors = Terasawa T, Blackmore CC, Bent S, Kohlwes RJ | title = Systematic review: computed tomography and ultrasonography to detect acute appendicitis in adults and adolescents | journal = Annals of Internal Medicine | volume = 141 | issue = 7 | pages = 537–546 | date = October 2004 | pmid = 15466771 | doi = 10.7326/0003-4819-141-7-200410050-00011 | s2cid = 46371675 }}</ref>

====Ultrasound====
[[File:SonoAppendizitis.JPG|thumb|An [[ultrasound]] image of acute appendicitis in December 2008]]
[[Abdominal ultrasonography]], preferably with [[doppler sonography]], is useful to detect appendicitis, especially in children. Ultrasound can show the free fluid collection in the right iliac fossa, along with a visible appendix with increased blood flow when using color Doppler, and noncompressibility of the appendix, as it is essentially a walled-off abscess. Other secondary sonographic signs of acute appendicitis include the presence of echogenic mesenteric fat surrounding the appendix and the acoustic shadowing of an appendicolith.<ref name="ReferenceA">{{cite journal | vauthors = Reddan T, Corness J, Mengersen K, Harden F | title = Ultrasound of pediatric appendicitis and its secondary sonographic signs: providing a more meaningful finding | journal = Journal of Medical Radiation Sciences | volume = 63 | issue = 1 | pages = 59–66 | date = March 2016 | pmid = 27087976 | pmc = 4775827 | doi = 10.1002/jmrs.154 | author3-link = Kerrie Mengersen }}</ref> In some cases (approximately 5%),<ref>{{cite journal|vauthors=Reddan T, Corness J, Mengersen K, Harden F|title=Sonographic diagnosis of acute appendicitis in children: a 3-year retrospective|journal=Sonography|volume=3|issue=3|pages=87–94|date=June 2016|doi=10.1002/sono.12068|s2cid=78306243|doi-access=free}}</ref> ultrasonography of the [[iliac fossa]] does not reveal any abnormalities despite the presence of appendicitis. This false-negative finding is especially true of early appendicitis before the appendix has become significantly distended. Also, false-negative findings are more common in adults where larger amounts of fat and bowel gas make visualizing the appendix technically difficult. Despite these limitations, sonographic imaging with experienced hands can often distinguish between appendicitis and other diseases with similar symptoms. Some of these conditions include [[inflammation]] of [[lymph nodes]] near the appendix or pain originating from other pelvic organs such as the ovaries or Fallopian tubes. Ultrasounds may be either done by the radiology department or by the emergency physician.<ref>{{cite journal |last1=Lee |first1=Sun Hwa |last2=Yun |first2=Seong Jong |title=Diagnostic performance of emergency physician-performed point-of-care ultrasonography for acute appendicitis: A meta-analysis |journal=The American Journal of Emergency Medicine |date=April 2019 |volume=37 |issue=4 |pages=696–705 |doi=10.1016/j.ajem.2018.07.025 |pmid=30017693|s2cid=51677455 }}</ref>

<gallery>
File:UOTW 45 - Ultrasound of the Week 1.webm|Ultrasound showing appendicitis and an appendicolith<ref name=UOTW45>{{cite web|title=UOTW #45 - Ultrasound of the Week|url=https://www.ultrasoundoftheweek.com/uotw-45/|website=Ultrasound of the Week|date=25 April 2015|url-status=live|archive-url=https://web.archive.org/web/20170509131322/https://www.ultrasoundoftheweek.com/uotw-45/|archive-date=9 May 2017}}</ref>
File:UOTW 45 - Ultrasound of the Week 3.jpg|Ultrasound showing appendicitis and an appendicolith<ref name=UOTW45/>
File:Ultrasonography of a normal appendix, annotated.jpg|Ultrasound of a normal appendix for comparison
File:Ultrasonography of a normal appendix without and with compression.jpg|A normal appendix without and with compression. Absence of compressibility indicates appendicitis.<ref name="ReferenceA"/>
</gallery>

====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"/>

====Magnetic resonance imaging====
[[Magnetic resonance imaging]] (MRI) use has become increasingly common for diagnosis of appendicitis in children and pregnant patients due to the radiation dosage that, while of nearly negligible risk in healthy adults, can be harmful to children or the developing baby.<ref>{{Cite journal |last1=D'Souza |first1=Nigel |last2=Hicks |first2=Georgina |last3=Beable |first3=Richard |last4=Higginson |first4=Antony |last5=Rud |first5=Bo |date=2021-12-14 |editor-last=Cochrane Colorectal Group |title=Magnetic resonance imaging (MRI) for diagnosis of acute appendicitis |journal=Cochrane Database of Systematic Reviews |language=en |volume=2021 |issue=12 |pages=CD012028 |doi=10.1002/14651858.CD012028.pub2 |pmc=8670723 |pmid=34905621}}</ref> In pregnancy, it is more useful during the second and third trimester, particularly as the enlargening uterus displaces the appendix, making it difficult to find by ultrasound. The periappendiceal stranding that is reflected on CT by fat stranding on MRI appears as an increased fluid signal on T2 weighted sequences. First-trimester pregnancies are usually not candidates for MRI, as the fetus is still undergoing [[organogenesis]], and there are no long-term studies to date regarding its potential risks or side effects.<ref>{{cite journal | vauthors = Burke LM, Bashir MR, Miller FH, Siegelman ES, Brown M, Alobaidy M, Jaffe TA, Hussain SM, Palmer SL, Garon BL, Oto A, Reinhold C, Ascher SM, Demulder DK, Thomas S, Best S, Borer J, Zhao K, Pinel-Giroux F, De Oliveira I, Resende D, Semelka RC | title = Magnetic resonance imaging of acute appendicitis in pregnancy: a 5-year multi-institutional study | journal = American Journal of Obstetrics and Gynecology | volume = 213 | issue = 5 | pages = 693.e1–6 | date = November 2015 | pmid = 26215327 | doi = 10.1016/j.ajog.2015.07.026 }}</ref>

====X-ray====
[[File:AppendicolithPlainXray.png|thumb|Appendicolith as seen on plain X-ray]]
In general, plain abdominal radiography (PAR) is not useful in making the diagnosis of appendicitis and should not be routinely obtained from a person being evaluated for appendicitis.<ref>{{cite journal | vauthors = Rao PM, Rhea JT, Rao JA, Conn AK | title = Plain abdominal radiography in clinically suspected appendicitis: diagnostic yield, resource use, and comparison with CT | journal = The American Journal of Emergency Medicine | volume = 17 | issue = 4 | pages = 325–328 | date = July 1999 | pmid = 10452424 | doi = 10.1016/S0735-6757(99)90077-3 }}</ref><ref>{{cite journal | vauthors = Boleslawski E, Panis Y, Benoist S, Denet C, Mariani P, Valleur P | title = Plain abdominal radiography as a routine procedure for acute abdominal pain of the right lower quadrant: prospective evaluation | journal = World Journal of Surgery | volume = 23 | issue = 3 | pages = 262–264 | date = March 1999 | pmid = 9933697 | doi = 10.1007/pl00013181 | s2cid = 23733164 }}</ref> Plain abdominal films may be useful for the detection of [[ureter]]al [[calculus (medicine)|calculi]], [[small bowel obstruction]], or [[perforated ulcer]], but these conditions are rarely confused with appendicitis.<ref name=Sabiston>[http://www.uptomed.ir/Digimed.ir/sabiston-2009/Sabiston_2009/HTML/473.htm APPENDICITIS from Townsend: Sabiston Textbook of Surgery on MD Consult<!-- Bot generated title -->] {{webarchive |url=https://web.archive.org/web/20131203014844/http://www.uptomed.ir/Digimed.ir/sabiston-2009/Sabiston_2009/HTML/473.htm |date=December 3, 2013 }}</ref> An opaque [[fecalith]] can be identified in the right lower quadrant in fewer than 5% of people being evaluated for appendicitis.<ref name=CDEM/> A [[barium enema]] has proven to be a poor diagnostic tool for appendicitis. While failure of the appendix to fill during a barium enema has been associated with appendicitis, up to 20% of normal appendices do not fill.<ref name=Sabiston/>