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1、Case Discussion,Tang Chun Xiang 2016/5/25,Axial arterial phase,Axial arterial phase,Axial venous phase,Coronal arterial phase,Sagittal venous phase,Crohn disease,An inflammatory disease of the gastrointestinal tract that typically has an indolent courseCharacterized by intestinal ulceration, strictu
2、res, and fistula formationCommonly affects young adults, small bowel, particularly the terminal ileumSmall bowel involvement in Crohn disease is typically transmural, with skip lesionsCT and MRI,Introduction-Crohn disease,CT and MRIUseful for differentiating between active and fibrotic bowel strictu
3、resAllowing visualization of the entire thickness of the bowel wallDepicting extraenteric involvementProviding more detailed and comprehensive information about the extent and severity,Introduction-Crohn disease,Comb signFat halo signBowel wall enhancementBowel wall thicknessStricture and fistulaMes
4、enteric/intra-abdominal abscess (15%-20%) or phlegmon formationUlcerations and loss of haustrationCreeping fat,Imaging findings on CT and MRI,Comb signProminence of the vasa recta adjacent to the inflamed loop of bowelTransmural extension of inflammation across the serosa and to engorgement of the h
5、yperemic vasa recta surrounding the inflamed bowel segmentNot pathognomic of Crohn disease,Imaging findings on CT and MRI,Fat halo signInfiltration of the submucosa with fat, between the muscularis and the mucosaConfused with the fat ring sign of mesenteric panniculitisNearly pathognomonic of inflam
6、matory bowel disease (Crohn disease and ulcerative colitis),Imaging findings on CT and MRI,Bowel wall enhancementThe result of increased vascular permeability and angiogenesisThe most sensitive indicator of active Crohn diseaseEnhancement can be graded by comparing to the precontrast imagesMinor inc
7、reased enhancementModerate enhancementMarked enhancementNo abnormal enhancement: equivalent to normal bowel wall,Imaging findings on CT and MRI,Pattern of enhancement,Bowel wall thicknessNormal bowel wall thickness： lumen distended， 1-2 mm； lumen collapsed, 3-4 mmMild: 3-5 mmModerate: 5-7 mmMarked:
8、7mmOne of the most common signs, but not specificCorrelates well with the severity of the disease activity Measure when lumen distended well Black border artifacts can distort thickness measurements,Imaging findings on CT and MRI,StrictureA complication of Crohn diseaseReversible strictures produced
9、 by active diseaseA lack of enhancement and loss of stratification might be seen in the presence of transmural fibrosis,Imaging findings on CT and MRI,FistulaThe detection of penetrating disease is important and may redirect or alter managementEnteroenteric fistula, enterovesical fistula, and interl
10、oop abscessCT enterography resulted in accurate detection of fistulas in 94% of cases,Imaging findings on CT and MRI,AbscessOften seen in patients with severe active Crohn diseaseExtraluminal fluid collections without communication with the bowel lumenFluid collections with an enhancing wall with or
11、 without associated air,Imaging findings on CT and MRI,UlcerationModerate to deep ulceration can be seen, small ulcerations can be difficult to distinguishActive spots of inflammationIncreased enhancement,Imaging findings on CT and MRI,Loss of haustrationBoth the colon and the small bowel are involv
12、ed in 30%60%Involvement of the colon alone in 20%35%A decrease of haustral foldsA common finding in ulcerative colitis,Imaging findings on CT and MRI,Creeping fatFibrofatty proliferation of fat wrapping, different name for hypertrophy of the subserosal fatCommon finding in longstanding Crohn disease
13、The image shows creeping fat surrounding bowel loops,Imaging findings on CT and MRI,CT and MRIUseful for differentiating between active and fibrotic bowel strictures,Summary,CT features of active Crohn diseaseMucosal hyperenhancementWall thickening (thickness 3 mm)Mural stratification with a promine
14、nt vasa recta (comb sign),CT features of inactive longstanding Crohn diseaseSubmucosal fat deposition (fat halo sign)Surrounding fibrofatty proliferation (creeping fat), and fibrotic strictures Pseudosacculation,CT and MRIAllowing visualization of the entire thickness of the bowel wall,Summary,Norma
15、l bowel wall thickness： lumen distended， 1-2 mm； lumen collapsed, 3-4 mmMild: 3-5 mmModerate: 5-7 mmMarked: 7mm,CT and MRIDepicting extraenteric involvement,Summary,Fistula and abscessEnteroenteric fistulaEnterovesical fistulaInterloop abscessEtc.,CT and MRIProviding more detailed and comprehensive information about the extent and severity,Summary,The extent and severity correlates with the diseaseThe degree of thickeningThe intensity of enhancementFistulas and abscessThe presence of ulcerations and loss of haustration,THANK YOU!,
