Editing Ulcerative colitis (section)

=== Imaging ===
Overall, imaging tests, such as [[x-ray]] or CT scan, may be helpful in assessing for complications of ulcerative colitis, such as perforation or toxic megacolon. Bowel ultrasound (US) is a cost-effective, well-tolerated, non-invasive and readily available tool for the management of patients with inflammatory bowel disease (IBD), including UC, in clinical practice.<ref>{{cite journal | vauthors = Bryant RV, Friedman AB, Wright EK, Taylor KM, Begun J, Maconi G, Maaser C, Novak KL, Kucharzik T, Atkinson NS, Asthana A, Gibson PR | title = Gastrointestinal ultrasound in inflammatory bowel disease: an underused resource with potential paradigm-changing application | journal = Gut | volume = 67 | issue = 5 | pages = 973–985 | date = May 2018 | pmid = 29437914 | doi = 10.1136/gutjnl-2017-315655 | s2cid = 3344377 }}</ref> Some studies demonstrated that bowel ultrasound is an accurate tool for assessing disease activity in people with ulcerative colitis.<ref>{{cite journal |last1=Allocca |first1=Mariangela |last2=Filippi |first2=Elisabetta |last3=Costantino |first3=Andrea |last4=Bonovas |first4=Stefanos |last5=Fiorino |first5=Gionata |last6=Furfaro |first6=Federica |last7=Peyrin-Biroulet |first7=Laurent |last8=Fraquelli |first8=Mirella |last9=Caprioli |first9=Flavio |last10=Danese |first10=Silvio |title=Milan ultrasound criteria are accurate in assessing disease activity in ulcerative colitis: external validation |journal=United European Gastroenterology Journal |date=May 2021 |volume=9 |issue=4 |pages=438–442 |doi=10.1177/2050640620980203 |pmid=33349199 |pmc=8259285 |doi-access=free }}</ref><ref>{{cite journal |last1=Allocca |first1=Mariangela |last2=Fiorino |first2=Gionata |last3=Bonovas |first3=Stefanos |last4=Furfaro |first4=Federica |last5=Gilardi |first5=Daniela |last6=Argollo |first6=Marjorie |last7=Magnoni |first7=Paola |last8=Peyrin-Biroulet |first8=Laurent |last9=Danese |first9=Silvio |title=Accuracy of Humanitas Ultrasound Criteria in Assessing Disease Activity and Severity in Ulcerative Colitis: A Prospective Study |journal=Journal of Crohn's and Colitis |date=28 November 2018 |volume=12 |issue=12 |pages=1385–1391 |doi=10.1093/ecco-jcc/jjy107 |pmid=30085066 |pmc=6260119 |doi-access=free }}</ref><ref>Piazza O Sed N, Noviello D, Filippi E, Conforti F, Furfaro F, Fraquelli M, Costantino A, Danese S, Vecchi M, Fiorino G, Allocca M, Caprioli F. Superior predictive value of transmural over endoscopic severity for colectomy risk in ulcerative colitis: a multicentre prospective cohort study. J Crohns Colitis. 2024 Feb 26;18(2):291-299. doi: 10.1093/ecco-jcc/jjad152. PMID: 37632350; PMCID: PMC10896635.</ref> Imaging is otherwise of limited use in diagnosing ulcerative colitis.<ref name="Ungaro" /><ref name="Feuerstein_UC" /> Magnetic resonance imaging (MRI) is necessary to diagnose underlying PSC.<ref name="Feuerstein_UC" />

Abdominal xray is often the test of choice and may display nonspecific findings in cases of mild or moderate ulcerative colitis. In circumstances of severe UC, radiographic findings may include thickening of the mucosa, often termed "thumbprinting", which indicates swelling due to fluid displacement (edema). Other findings may include colonic dilation and stool buildup evidencing constipation.<ref name=":4" />

Similar to xray, in mild ulcerative colitis, double contrast barium enema often shows nonspecific findings. Conversely, barium enema may display small buildups of barium in microulcerations. Severe UC can be characterized by various polyps, colonic shortening, loss of haustrae (the small bulging pouches in the colon), and narrowing of the colon. It is important to note that barium enema should not be conducted in patients exhibiting very severe symptoms as this may slow or stop stool passage through the colon causing ileus and toxic megacolon.<ref name=":4" />

Other methods of imaging include computed tomography (CT) and magnetic resonance imaging (MRI). Both may depict colonic wall thickening but have decreased ability to find early signs of wall changes when compared to barium enema. In cases of severe ulcerative colitis, however, they often exhibit equivalent ability to detect colonic changes.<ref name=":4" />

Doppler ultrasound is the last means of imaging that may be used. Similar to the imaging methods mentioned earlier, this may show some thickened bowel wall layers. In severe cases, this may show thickening in all bowel wall layers (transmural thickness).<ref name=":4" />