J. Coloproctol. (Rio J.) vol.37 número3

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jcoloproctol(rioj).2017;37(3):251–254

w w w . j c o l . o r g . b r

Journal

of

Coloproctology

Review

Article

Computed

tomography

enterography

and

magnetic

resonance

enterography

in

small

intestine

of

Crohn’s

disease

Aida

Cristina

Correia

Oliveira

Azevedo

a,b

,

Sandra

Fátima

Fernandes

Martins

a,b,c,∗

a_Universidade_do_Minho,_Escola_de_Ciências_da_Saúde,_Life_and_Health_Sciences_Research_Institute_(ICVS),_Braga,_Portugal

b_ICVS/3B’s,_PT_Government_Associate_Laboratory,_{Braga/Guimarães,}_Portugal

c_Centro_Hospitalar_de_{Trás-os-Montes}_e_Alto_Douro,_Departamento_de_Cirurgia,_Vila_Real,_Portugal

a

r

t

i

c

l

e

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n

f

o

Keywords:

Inflammatoryboweldisease Crohn’sdisease

CRenterography MRIenterography

a

b

s

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c

t

Crohndiseaseisdefinedasachronicinflammatoryandidiopathicprocessthatcanaffect anyportionofthegastrointestinaltract.Thesmallintestineisthemostfrequentlyaffected place,sosmallbowelmorphologyinvestigationisoftenmandatory.

Fordecadessmallbowelwasalmostinaccessibletoendoscopies,and,studieslike entero-clysisandboweltransittimetest,wereconsideredgoldstandardtests.Recently,innovative imagingtechniques,improveddiagnosisandfollow-upofCrohndiseasepatientsby allow-ingtheexplorationofthisgutsegment.

Authorsreviewliterature,concerningtheroleofcomputedtomographyenterographyand magneticresonanceenterographyintheevaluationofsmallbowelCrohndisease.

Authorsconcludethatthechoiceofexaminationtobemadeshouldbeweighted consid-eringseveralfactorssuchastheageofthepatient,theirtolerability,theCrohn’sdisease phenotypeandtheavailabilityofhospitalresources.

Enterografia

por

tomografia

computorizada

e

por

ressonância

magnética

na

avaliac¸ão

da

Doenc¸a

de

Crohn

do

intestino

delgado

Palavras-chave:

Doenc¸ainflamatóriaintestinal Doenc¸adeCrohn

EnterografiaporTC EnterografiaporIRM

r

e

s

u

m

o

Adoenc¸adeCrohnédefinidacomoumprocessoinflamatórioeidiopáticocrônicoquepode afetarqualquerpartedotratogastrintestinal.Ointestinodelgadoéolocalmais frequente-menteafetadoe,assim,comfrequênciatorna-seobrigatóriaumainvestigac¸ãodamorfologia dointestinodelgado.

Durantedécadas,ointestinodelgadoerapraticamenteinacessívelàsendoscopias;nesse contexto,estudoscomoaenterócliseeadeterminac¸ãodotempodetrânsitointestinaleram

∗ _{Corresponding}_author_.

E-mail:sandramartins@ecsaude.uminho.pt(S.F.Martins). http://dx.doi.org/10.1016/j.jcol.2017.06.002

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consideradoscomooscritériosdiagnósticosprincipais.Recentemente,técnicas imaginológ-icasinovadoras aperfeiçoaramodiagnósticoeseguimentodepacientescomdoençade Crohn,porpermitiremaexploraçãodessesegmentointestinal.

Osautoresrevisamaliteraturapertinenteaopapeldaenterografiaportomografia com-putadorizadaedaenterografiaporressonânciamagnéticanaavaliac¸ãodadoenc¸adeCrohn nointestinodelgado.

Osautoresconcluemqueaescolhadoexameaserrealizadodevelevaremconta diver-sosfatores,comoaidadedopaciente,tolerabilidade,ofenótipodadoenc¸adeCrohnea disponibilidadedosrecursoshospitalares.

Inflammatoryboweldisease(IBD)encompassesagroupof disorderscharacterizedbyaninappropriateimmuneresponse toendogenousintestinal microbialflora, withorwithout a componentofautoimmunity.1

Geographical distribution of IBD is not homogeneous, aroundtheworld,andahigherincidenceisobservedin West-erncountries,ontheotherhand,itisalsoanemergingdisease, incountriesthathaveadoptedmorewesternizedhabitsand stylesoflife.1,2

IBD,incidencehasbeenincreasingoverthelastyears,in all age groups. With regard specifically to Crohn’s disease (CD)itsincidenceisof0.1–16casesper100000inhabitants, worldwide.3_In_Europe,_it_is_estimated_that_12.7_new_cases_of CDarediagnosedperyear,per100000inhabitants.4

CDcanaffectanyportionofthegastrointestinaltract,from themouthtotheanus.However,inapproximately30–40%of patientswithCD,onlythesmallintestineisaffected, particu-larlytheterminalileum,in15–25%onlythecolonisaffected andbothcolonandsmallintestineisaffectedin40–55%ofthe patients.1,5

Regardless of the advances that have occurred at the level ofknowledge ofthe basic mechanisms of inflamma-tionandpathogenesisofCD,itsetiologyremainsunknown. Itisaccepted, however,that somegenetic,microbiological, immunological, environmental, dietary, vascular and psy-chosocialfactors,suchassmoking,useoforalcontraceptives andnonsteroidalanti-inflammatorydrugs,haveinfluencein theindividualsusceptibilitytodevelopthedisease.1,6

Clinical presentation of the disease is characterized by asymptomaticperiodsalternatingwithexacerbationperiods, withvariable time intervals.5 _A _panoply _of_symptoms _and signs,canbeobserved,beingthemostfrequent,abdominal pain,diarrhea,weightlossandfever.7_Rectal_bleeding_and vita-mindeficits,althoughless frequent,canalsobepresent.1,8 Extra-intestinalmanifestations,canalsobeseenin15–20% ofpatients, mostlywomen withcolic CD,like orallesions, erythemanodosum,episcleritisandinvolvementofthe mus-culoskeletalandhepatobiliarysystems.1,8 _More_rarely,_lung, kidney,pancreas,heartandcentralnervoussystem involve-mentandpsychosocialdisorderssuchasdepression,anxiety anddifficultiesinacceptingbodyimagecanbedocumented.9 InordertofacilitatethecharacterizationofCD,particularly inregardtoitsseverity,itispossibletocategorizethedisease basedontheMontrealClassification,thatclassifiespatients

basedintheageofpresentation;maximallocationofdisease beforethefirstsurgeryanddiseasebehavior.Theapplication ofthisclassificationisrecommended5yearsafterdiagnosis ofthedisease.6

CD diagnosis is based on four pillars: clinical history, endoscopy, imaging/radiology exams and histopathology.8 Undoubtedly,colonoscopyistheelectiontestforCDdiagnosis byallowingacompleteviewoftheentirecolon,ileocecalvalve and terminalileum, which are the anatomical areas most commonly affected, aswell as, performing biopsiesof the involved areas,10,11 _mandatory_for _definitive_diagnosis._The characteristicendoscopicfindingsincludeskiplesions, apht-housulcersandamucosalpatternincobblestone,frequently involvingtheterminalileumandsparingtherectum.10 Histo-logicalfindingsinfavorofthechronicityoftheinflammatory processarethedistortionofarchitecture,increased cellular-ityinthelaminapropria,metaplasiaofthepyloricglandand Panethcells.Althoughthepresenceofgranulomasishighly suggestiveofCD,itisnotconsideredpathognomonicandcan befoundinmanyotherconditionsincludingCU,tuberculosis andsarcoidosis.10

Colonoscopyalsoallowstoevaluatetreatmentsoutcomes, namely; aftertreatment withbiological and standard ther-apy;stricturesdilationwiththeballoontechnique.Prospective studieshaveshownthatcolonoscopyisasafemethodwitha lowrateofadverseeffectsinpatientswithIBD.12

Thesmall bowel isthe segment moreoften affectedby CD.1,5 _The _evaluation _of _this _segment _is _hindered _by sev-eralfactorssuchasitslengthandpositionintheabdominal cavity,itstortuosityandoverlappinghandlesandforhaving apleatedmucosa.13 _Regarding _the_{investigation} _of_the dis-ease inthis location,fordecades,studies withbarium,for example,enteroclysisandboweltransittimetest,were con-sideredgoldstandardtests,withgreatimpactondiagnosis, assessment of their anatomical distribution and detection

offistulae,abscessesandsignsofthedisease’sactivephase

or exacerbations.1,13 _However, _given _the _progress _that _has beenoperatedinthefieldofimaging,especiallyintermsof improvementofimagingtechniques,enterography,eitherCT (CTE)ormagneticresonanceimaging(MRIE),hasbeen sup-plantingtheprevioustechniquesthatwereusedtostudythe diseaseinthesmallintestine.1,14

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Table1–Overallsensitivityandspecificityofcomputedtomographyenterographyandmagneticresonanceenterography intheevaluationofsmallbowelCrohndisease.

CTE MRIE

Sensitivity(%) Specificity(%) Sensitivity(%) Specificity(%)

Cakmakcietal.11 ₁₀₀ _53.9 _nr

Ohtsukaetal.18 _85.8 _83.6 _87.9 _81.2

CTE,computedtomographyenterography;MRIE,magneticresonanceenterography;nr,notreported.

withnooverlapofintestinalloops,allowingtheobservationof theintestinalwall,thedetectionofextra-luminaldiseaseand otherpotentialalterationsassociated.11_In_fact,_the_fine_cuts andmultiplanarreconstructionsthatthisimagingtechnique allows,canovercomebarrierstoviewthesmallintestinesuch asthesuperpositionofloopsanditsextension.1,11

The distinction between active disease and disease in chronicphaseisveryimportantparticularlysothatthemost appropriatetreatmentcanbeapplied,this is,patientswith imagingfindingscharacteristicofacutediseasebenefitfrom treatment with corticosteroids while in the chronic phase thebesttreatmentoptioninvolvessurgeryorotherinvasive procedures.15

RegardingCTE,thepresenceofwallthickening,increased enhancementoftheintestinalwall,wallstratification, densi-ficationofthemesentericfat,engorgementofthevasarecta, lymphadenopathy,fistulaeandabscesses,areconsidered sug-gestiveimagingfindingsofCD’sactivephase.2,16

RecentstudieswithCTErevealedasensitivityof100%and aspecificityof53.9%forthediagnosisofactiveCD.11

ConcerningMRIE,thetranslation ofCD’sactivephaseis supportedbythevisualizationofenhancementofthemucosa, wallstratification,ulcers,densificationofthemesentericfat, wallthickening, engorgement ofthe vasa recta,strictures, mesentericlymphadenopathy,fistulaeandabscesses.11,17

Datafromameta-analysisof290patientswithCDfrom6 studies,setthesensitivityandspecificityofCTEinthe evalu-ationandmonitoringofCD’sactivephasein85.8%and83.6%, respectively;inthecaseofMRIE,thesensitivityis87.9%and specificityof81.2%.18

The fistulae, strictures and abscesses detection rate is

96.3%,61.6%and89.9%respectively,whenusingtheCTEand 93.6%,93.1%and99.6%whenusingtheMRIE.18

ThemaindisadvantageofusingCTEistheuseofionizing radiationwhichisofparticularimportanceinyoungpatients withtheneedoffrequentimagingmonitoringoftheresponse totherapy.15

TheMRIE,animagingtechniquethatworkswithoutthe useofionizingradiation,hasgoodsofttissuecontrastanda betterdistinctionbetweenthefluidcontentandedema.Italso allowstoinfertheintestinalmotility,whichisnotpossible withCTE.19_However,_it_should_be_noted_that_there_are_some contraindicationsforperformingMRIEsuchasifthepatient hasimplants,allergytocontrastordecreasedrenalfunction.20 Finally,it shouldbenoted thatstudieswhereMRIEwas compared with CTE, no statistically significant differences were found in the effectiveness of the evaluation of CD’s activity.Ameta-analysisbyHorsthuisetal.alsoreportedno significantdifferencesbetweentheCTEandMRIEandits diag-nosticcapacityandinflammatoryboweldiseasemonitoring.21

Table2–Percentageofdetectionoftheprincipal’s findingsofCrohndisease,bycomputedtomography enterographyandmagneticresonanceenterography.18

CTE(%) MRIE(%)

Fistulaedetectionrate 96.3 93.6

Stricturesdetectionrate 61.6 93.1

Abscessesdetectionrate 89.9 99.6

CTE,computedtomographyenterography; MRIE,magnetic reso-nanceenterography.

Tables1and2summarizetheprincipalresultsofcomputed tomographyenterographyandmagneticresonance enterogra-phyintheevaluationofsmallbowelCrohndisease.

Considering,now,thetreatmentofCD,theprimary end-pointistheinductionofremissionand,often,thisisachieved withthe useofcorticosteroidsorallyadministered.Incase ofrelapsewiththeuseofcorticosteroidsalone,itis recom-mended the association ofan immunomodulator, such as azathioprine.Referencetoaspecializedcenterandtheuseof biologicaltherapy(includinganti-TNFalphaantibodies: adali-mumab,infliximab,andothers)shouldbeconsideredincases ofrelapsingdiseaseorresistancetocorticosteroids.1,8

Compliancewiththetreatmentalsohassecondary objec-tives,asthemaintenanceofremissionandpreventionoflate complications. Maintenance of remission is achieved with azathioprinewhichisthefirst-linedrug.Methotrexateisan alternative,withthesamedegreeofefficacy,beingthedrug usedincaseofintolerancetothiopurines.1,8

Early use of biological therapy brings benefits in terms of reducing the number of hospitalizations and surgeries, however, besidesbeingacostly therapy, itisnot freefrom infectiousrisksorreactionsassociatedwiththeinfusion.1,8

TheidentificationofindividualswithCDlikelytodevelop complicationsinthecourseofthediseasecanbemadeby tak-ingintoaccountsomefactorssuchasearlyageatdiagnosis, perianaldisease,phenotypicallystricturingdisease,severity ofdiseaseatdiagnosis(basedonthepercentageofweightloss orneedforcorticosteroidsatdiagnosis).Itisknownthat90%of patientswhopresentthreeormoreofthesefactors,willhave aworseoutcomein5yearsandmayrequiretwoormore resec-tions,adefinitivestomaordevelopcomplexperianaldisease.8

Conclusion

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DifferenttechniquessuchasEDB,ETC andERM,can be usedtofollowCD.

Thechoiceofexaminationtobemadeshouldbeweighted consideringseveralfactorssuchastheageofthepatient,their tolerability,theCDphenotypeandtheavailabilityofhospital resources.

Conflicts

of

interest

Theauthorsdeclarenoconflictsofinterest.

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