MR imaging of Crohn's disease: The experience at the Royal Melbourne Hospital

Abstract

Experience at our hospital departmentDuringtheperiodOctober2001toNovember200,weperformed 80 MRI examinations on 73 patients (seven had two scans) for Crohn's disease. Forty-eight of the patients were female (66%) and 25 patients male (3%). The average age of the female patients was 38 years (range 17-81) and the male IntroductionCrohn's disease is a chronic inflammatory bowel disease affectingthegastro-intestinal(GI)tractanywherefromthemouth totheanus.Thesmallbowelisaffectedin80%ofcases,most commonlyattheterminalileum.1 Thelargebowelisalsoaffected (20% of the time alone and 50% of the time with the small bowel).2 Thediseaseischaracterisedby'skip'lesionsofnormal and diseased bowel, epitheloid cell granulomas and transmural inflammationoftheaffectedareas.Symptomsincludeabdominalpain,diarrhoea,rectalbleeding, fevers and weight loss and gross pathologic findings include: inflamedbowelwall,enlargedmesentericlymphnodesandthe formationofabdominalandpelvicfistulas. 3ItisacharacteristicofCrohn'sdiseaseforsuffererstoundergo periods of remission and relapse, 1 and it is also not unusual for these patients to undergo surgery to remove affected segments ofbowel.Thecauseofthediseaseisunknownanditmostcommonlyaffectsyoungadults.The medical management of Crohn's disease depends upon on the severity and status of the disease. Medication given to helpmanagetheinflammatoryresponseofthebowelaswellas bacterial over-growth include: immunosuppressants, antiinflammatoriesandantibiotics. Hospital practice and methodologyOurprotocolforacomprehensivemagneticresonanceimaging(MRI)examinationofthesmallbowelincludesbothT1and T2 weighted imaging sequences and post-contrast T1 weighted images.3,5 As with a computer ised tomography (CT) examinationoftheabdomenandpelvis,itisveryimportanttoutiliseoral contrastpriortothescaninordertoadequatelydistendthebowel loops, thus allowing for correct assessment of disease activity withinthebowelwall.3 Atourdepartmentthepatientdrinks1Lof abarium-sulphatesuspension(Redicat ® -2)whichappearsaslowsignalintensityonT1-weightedimagesandhigh-signalintensity on T2-weighted images. We also distend the large bowel with 700mlofwateradministeredasanenema.Thepatientmustalso MR imaging of Crohn