Adverse events of computed tomography colonography: An Italian National Survey

ContentslistsavailableatSciVerseScienceDirect

Digestive

and

Liver

Disease

jo u r n al h om e p a g e :w w w . e l s e v i e r . c o m / l oc a t e / d l d

Alimentary

Tract

Adverse

events

of

computed

tomography

colonography:

An

Italian

National

Survey

夽

Franco

Iafrate

_,

_Gabriella

_Iussich

_,

_Loredana

_Correale

_,

_Cesare

_Hassan

_,

Daniele

Regge

_,

_Emanuele

_Neri

_,

_Paolo

_Baldassari

_,

_Maria

_Ciolina

_,

Alessandro

Pichi

_,

_Marcella

_Iannitti

_,

_Davide

_Diacinti

_,

_Andrea

_Laghi

a_{DepartmentofRadiologicalSciences,OncologyandPathology,“Sapienza”UniversityofRome,Rome,Italy}

b_{RadiologyUnit,InstituteforCancerResearchandTreatment,Candiolo,Italy}

c_{im3D,MedicalImagingLab,S.p.A,Torino,Italy}

d_{GastroenterologyUnit,“NuovoReginaMargherita”Hospital,Rome,Italy}

e_{UniversityofPisa,DiagnosticandInterventionalRadiology,Pisa,Italy}

a

r

t

i

c

l

e

i

n

f

o

Articlehistory:

Received26October2012

Accepted27February2013

Available online 2 May 2013 Keywords: Coloncancer CTcolonography Perforation Survey Vasovagalsyncope Virtualcolonoscopy

a

b

s

t

r

a

c

t

Aim:Toretrospectivelystudythefrequencyandmagnitudeofcomplicationsassociatedwithcomputed tomography(CT)colonographyinclinicalpractice.

Methods:AquestionnaireoncomplicationsofCTcolonographywassenttoItalianpublicradiology departmentsidentifiedaspracticingCTcolonographywithareasonableleveloftraining.Thefrequency ofcomplicationsandpossibleriskfactorswereretrospectivelydetermined.Responseswerecollated androwfrequenciesdetermined.Amultivariateanalysisofthefactorscausingadverseeventswasalso performed.

Results:40,121examinationswereperformedin13centersduringthestudyperiod.Nodeathswere reported.Bowelperforationsoccurredin0.02%(7exams).Allperforationswereasymptomaticand occurredinpatientsundergoingmanualinsufflation.Fiveperforations(71%)occurredinprocedures performedfollowingarecentcolonoscopy.Therewasnosignificantdifferencebetweenperforations associatedwithrectalballoon(0.017%)andthosethatwerenot(0.02%).Complicationsrelatedto vaso-vagalreaction(eitherwithorwithoutspasmolytic)occurredin0.16%(63exams).Allvasovagalreactions resolvedinlessthan3h,withoutanysequelae.

Conclusions:PerforationrateatCTcolonographyinItalyiscomparablewithelsewhereintheworld, occurringregardlessoftheexperienceofradiologycenters.Althoughtheriskisverysmall,itmaynotbe negligiblewhencomparedwiththeriskofdiagnosticcolonoscopy.

© 2013 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

1. Introduction

Computed tomographic colonography (CTC) is increasingly usedasarelativelynon-invasivemethodofcolonicinvestigation bothforcolorectalcancer(CRC)screening[1–3]andforpatients withsymptomssuggestiveofCRC[4–7].Datafromlargestudies onscreeningcohortshavesuggestedthat CTCand conventional colonoscopyhavesimilarsensitivityforpolyps≥6-mmin diame-ter[8,9].Moreover,patientsgenerallypreferCTCinsteadofbarium enemaexaminationorcolonoscopy[10–13].However,concerns

夽 Theresultsofthisresearchwerepresentedatthe2011RSNAMeetingCODE:

MSVG41-17SESSION:GastrointestinalSeries:CTColonographyUpdate,November

30,2011.

∗ Corresponding author at: DigestiveEndoscopy Unit, ONRM Hospital,Via

Morosini30,Rome,Italy.Tel.:+390658446608;fax:+390658446533.

E-mailaddress:cesareh@hotmail.com(C.Hassan).

wereraisedaboutrecommendingCTCasroutinescreeningtool becauseofpotentialharm[14,15].WhileCTCiswidelyconsidered tobemuchsaferthancolonoscopy[16–18],itisnotexemptfrom potentialseriouscomplications,mainlyrepresentedbylargebowel perforations[18–22].TheNationalSurveyofUnitedKingdom[18] hassuggested a perforationrate,for diagnosticstudies, of1 in every1889examinations.Similarly,in alargepopulation-based cohort,theincidenceofperforationswas0.058%,oronein1696 studies,withonein2967patientsrequiringsurgicalintervention [19].Theseratesarehigherthanthosereportedbythe Interna-tionalWorkingGrouponVirtualColonoscopy[20,21].Inthissurvey thetotalperforationrateforallpatientswas0.009%(2in21,923 studies)andsymptomaticperforationrate(requiringfurther treat-ment)was0.0054%(1in21,923).Higherratesofadverseevents (AEs)maybeasignofpoorqualityhospitalcareandmany com-plicationscanbepreventedifhospitalsfollowproceduresbased onthebestpracticeandscientificevidence[20,21].Ideally,forthe standardbestpractice,continuingtrainingshouldberequiredto

1590-8658/$36.00 © 2013 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

radiologistsortechnologistsperformingCTCexaminationsattheir institutions[19,23,24].

Thus,thepurposeofthisnationwidesurveyistoassessthe fre-quencyandthemagnitudeofcomplicationsassociatedwithCTC indailyclinicalpracticeatwell-trainedcenters.Thissettingisof interestsincepreviousstudieshaveprovideddatafrom special-izedcenters[19,20]anditremainsunknownwhetherresultsfrom thesestudiescanbegeneralized.

2. Methods

AquestionnaireaboutcomplicationsofCTcolonographywas senttoItalianpublicradiologydepartmentsidentifiedaspracticing CTcolonographywithareasonableleveloftraining.Thefrequency ofcomplicationsofCTcolonographyandpossibleriskfactorswere retrospectivelydetermined.Ethical approvaland informed con-sentwerewaived, sincethis studywasdeemedaclinicalaudit andpatientswouldnotbeapproached. Atthetime ofthis sur-vey,inItaly, there were40publicDepartmentsoffering CTCin theireveryday clinicalpracticewithdifferentlevelsofstandard care and another unknown number of private centers, whose expertiseisunknown[25].Apreliminaryletterwasmailedtothe clinicaldirectors of all publicdepartments. The letter included a brief description of the study and the permission to collect anonymousdatafromtheInstitution.Therespondentcenterswere re-contactedtoestablish eligibility.To beeligible, departments hadtoattend ororganize atleast 2CTCcourses recognizedby theItalianSocietyofRadiology(SIRM).Thiscriterionwasapplied to select centers attaining the goal of providing best practice. Althoughtherewerenorulestodefineprinciplesofbestpractice,it wasassumedthatradiologistsandtechniciansatqualifiedcenters hadtoundergotrainingincludingcontinuingmedicaleducation accreditedcourses[23,25].Thus,twoapprovedtrainingprograms wastheminimumrequirement.Ofthe24 (60%)respondents,8 centerswereexcludedbecausetheydidnotmeetourinclusion criterion;threeadditionalcenterswerealsoexcludedbecause eli-gibilitywasneverestablisheddespitemultipleattempts.Between December2010andDecember2012,anemailwassenttotheLead GastrointestinalRadiologistof eachparticipant centeraskingto completeadetailedquestionnaire(supplementaryTableS1).The questionnaireincludedwhentheCTCservicewasstarted(year) andthetotal numberofexaminationsperformedatthetime of thepresentsurvey.Theradiologistswereaskedhowmany com-plications(e.g.,colonic perforationsand vasovagal effects)they had experienced in theirinstitution. Additionalquestions were askedincluding the type of gasinflated (air or carbon dioxide –CO2),thetype ofcatheter usedforinflation (rigidor flexible,

withor withoutballoon), theuseof spasmolytics(i.e.Hyoscine N-butylbromide20mg/ml,1mlinjectablevials),thebowel prepa-ration given tothepatient (including diet, theuseof laxatives and fecal taggingagents); complications were registeredalong withpossibledeaths.Ifa complicationwasrecorded,additional detailsrelatedtothateventwereasked.Ifaperforationoccurred, thestaffmember performingtheinflation(radiologist,resident, nurse or technician), theseverity of the event, theperforation site (intra or retroperitoneal, determined onCT imagesby the distributionofgasintheabdomen)andthetypeoftreatment (con-servativeor surgical)were recorded.Additionalinformation on patientdemographicsincludingsex,age,comorbidities,previous surgicalinterventionandpreviousrecentlyperformedCCwasalso reported.

Patients included in the survey underwent CTC for both screening and diagnostic indications. All CTC procedures were acquiredbyusingdualpositioning(proneandsupinescans)anda supervisingradiologistorresident,thatcouldpromptlyrecognize

Table1

Characteristicsoftheincludedcentres.

Center CTCstudiesn(%) Perforationsn(%) Vasovagalreactionsn(%) Center1 1.030(2.6) 1(0.097) 3(0.03) Center2 565(1.5) 0(0) 1(0.18) Center3 1.190(2.9) 0(0) 3(0.25) Center4 1.088(2.7) 0(0.09) 4(0.37) Center5 1.267(3.2) 1(0.078) 11(0.87) Center6 3.420(8.5) 0(0) 3(0.09) Center7 500(1.3) 0(0) 3(0.6) Center8 9.322(23.2) 0(0) 9(0.096) Center9 6.029(15.0) 2(0.03) 11(0.18) Center10 6.177(15.4) 0(0) 0(0) Center11 5.034(12.5) 0(0) 4(0.079) Center12 3.183(7.9) 3(0.09) 6(0.188) Center13 1.316(3.3) 0(0) 5(0.38) Total 40.121(100) 7(0.017) 63(0.16)

theadverseeventduringCTCexaminationwithreal-time

evalua-tionofimages,wasoncallateachcenter.

2.1. Statisticalanalysis

Descriptiveanalysisincludedthecalculationofratesand

pro-portionsforcountdata.Univariateanalysiswascarriedoutwith

chi-squareprocedures.Multivariateanalysisofthemainpredictors

ofcomplicationswasperformedbyusinglogisticregressionmodel

[26,27].Becausetheunitofobservation(patient)wasdifferentfrom theunitofanalysis(center), awithin-center correlationof out-comeswastakenintoaccountbymeansofarandom-effectanalysis withgroupingbycenter[28].Centerswerealsoseparated accord-ingtothehospitalacademicstatus(academicvs.non-academic center).ThenumberofyearsofexperiencewithperformingCTC procedurewasalsocalculatedforeachcenter.Theeffectsof fac-torsofinterest(whethercategoricalorcontinuous)wereevaluated byoddsratios(ORs),alongwithconfidenceintervals(CIs)aswell asmodel-basedWaldtests.Allstatisticalanalysiswasperformed byusingsoftware(R;theRFoundation,Vienna,Austria)[29,30]. P-values<0.05wereconsideredtoindicatestatisticalsignificant.

3. Results

Thirteencenterswereidentifiedaseligibleandincludedinthe analysis.Ofthese,6(46%)werelocatedinnorthernItaly,5(39%) incentralItalyand2(15%)insouthernItaly.Overall6(46%) cen-terswereacademic,7non-academic.Duringtheevaluatedperiod from2000to2011,themeannumberofCTCproceduresperformed annuallybyeachcenterrangedfrom83to847.By2011,allcenters hadaccumulated4ormoreyearsofexperiencewithperforming CTCprocedure.Nine(69%)centershad8ormoreyearsof expe-rienceinCTCprocedure,withmorethan1000CTCexaminations percenterperformed(129–847proceduresperyear).Twocenters (15%)reportedofferingCTCservicein2005,havingperformeda totalof500and1088examinations,respectively.Theremaining2 (15%)centersofferedCTCservicein2006and2007(263and141 meanprocedures/year,respectively).

3.1. Examinationsperformed

Intotal,40,121CTCexaminationswereperformedatthe13 par-ticipatingcentersbetween2000and2011(meannumberofexams 3086±2773;range,500–9322).Table1reportsthedistributionof CTCexamspercenter.Thesixacademiccenterscontributed28,752 patientstothetotal40,121(72%).

Table2

Detailsofsevenperforations.Allperforationswereasymptomaticandperformedwithmanualinsufflationmethod.

Centerno. Treatment Catheter Operator Site Gasdistribution PriorCC Priorbiopsy Comitanta_disease

1 9 Surgery Foley Technician Rectum Retroperitoneal Yes2weeksbefore Yesb _No

2 13 Surgery Rigidwithballoon Nurse Sigmoid Peritonealand

retroperitoneal

Yessame-day No Diverticulosis

3 13 Surgery Rigidwithballoon Radiologist Sigmoid Retroperitoneal Yessame-day No No

4 1 Conservative Flexiblewithoutballoon Radiologist Rectum Retroperitoneal No No No

5 5 Conservative Foley Nurse Sigmoid Intraperitoneal Yes3daysbefore No Diverticulosis

6 9 Conservative Foley Resident Sigmoid Peritonealand

retroperitoneal

Yessame-day No Diverticulosis

7 13 Conservative Rigidwithballoon Radiologist Sigmoid Peritonealand

retroperitoneal

Yessame-day No No

a_{Pre-existingmedicalconditionssuchasinguinalhernia,carcinoma,diverticulosis.}

b_{Withoutelectrocauteryusingcoldbiopsyforceps.}

3.2. CTCtechnique

Colondistensionwasachievedviaroomairinsufflationin73% (29,373/40,121) of the patients; in the remaining10,748 cases (27%) an automaticCO2 insufflator wasused. Gas wasinflated

throughFoley cathetersin 63%of thepatients(25,361/40,121); ballooned-tippedflexiblecathetersin14%(5513/40,121);flexible catheterswithoutballoonin3%(1032/40,121);ballooned-tipped plasticlarge-borerigidcathetersin11%(4501/40,121)and plas-ticlarge-borerigidcatheterswithoutballoonin9%(3714/40,121). Spasmolyticagentswereusedin25,164patients(64%)toachievea bettercolonicdistension;thiswasnotnecessaryin14,957patients (36%).

3.3. Adverseevents 3.3.1. Vasovagalreactions

Sixty-three self-limiting vasovagal episodes were reported overall(0.16%;95%CIs,0.09–0.3%;eventoccurrence,oneevery638 procedures).

Allvasovagalreactionsweremanagedwithoutadditional med-icationsandresolvedinless than3h, withoutanysequelae.As showninTable1,vasovagalreactionsratesvariedwidelybetween centersfrom0%to0.86%.

Multivariateanalysisshowedthatpatientsfromacademic cen-terswerelesslikelytoexperiencevasovagalepisodesthanthose fromnon-academiccenters(ORs,0.33;95%confidence interval, 0.12–0.89;P=0.04).

3.3.2. Bowelperforations

There were 7 cases of bowel perforation (0.02%; 95% CIs: 0.007–0.04%,event occurrence, one every5732 studies), which occurredat4(2academicand2non-academic)centers.Atallfour centers,atotalof1000ormoreexamshadbeenperformed,and, collectivelythesecenterscontributedto11,509(29%)examinations included in ouranalysis. Patients who experienced perforation were71.4%male,meanagewas73years(range,64–78years).None ofthepatientsweresymptomatic.Characteristics fortheseven perforatedpatientsaresummarizedinTable2.

Noperforationsoccurredinpatientswhounderwent mechani-calCO2insufflation.Fivecasesofperforations(71%)occurredinCTC

examinationsperformedasstudiesfollowingCC:threeoccurred aftersame-dayCC (Fig.1)and two othersoccurredwithin 1–2 weeksafterCC.Four(57%)casesofperforationsoccurredinthe rectum(Fig.2);andthree inthesigmoidcolon.Overall,35,375 CTCexaminationswereperformedbyusinganinflatedballoonin therectum,andamongthese,thereweresixperforations.Further, 4746examinationswereperformedwithoutaninflatedballoon, andamong these,therewasone perforation.The proportionof perforationsassociatedwithrectalballoonwassimilartothe pro-portionof those that were not (0.017% vs. 0.02;P=0.5). Three

Fig.1.71-Year-oldmaleundergoingCTcolonographyonthesamedayof

conven-tionalcolonoscopy.Theimagesshowalargeamountoffreeairintheperitoneal

cavityduetosigmoidperforation.

perforationsoccurredamong8215patientspreviouslydistended by using a rigidcatheter (0.036%; one every 2738exams); the perforationratefromstudiesperformedwithaflexiblecatheter was0.012%(4/31,906;oneevery7978exams;P=0.3).Three per-forations occurredat twoacademic centers,theremainingfour perforations attwonon-academic centers.Multivariateanalysis showedthattherewerenosignificantdifferencesinperforation occurrencebetweenacademicandnonacademiccenters(ORs,0.37; 95%CIs,0.05–2.6;P=0.4).Boweldistensionwasperformedinthree cases(43%)byanattendingphysician,intwocases(29%)byanurse,

Fig.2.68-Year-oldmaleundergoingCTcolonographyforscreening.Theimages

showfreeretroperitonealairduetoperforationoftherectum.Afewairbubblesare

inonecase (14%)byaresidentinRadiologyandinthelastone (14%)byatechnician.Distributionofairwasretroperitonealin4 patients(57%)andinthethreeremainingcases(43%)gas distri-butioninvolvedbothretroperitoneumandperitonealspace.Three patientsunderwentsurgery(0.0075%surgeryrateforCTC-related perforation,oneeventin13,374procedures);theremainingfour patientsreceivedsuccessfulconservativetreatment.

Nodeathswerereported. 4. Discussion

In our national survey, the majority (90%) of all complica-tions of CTC were vasovagal reactions of mild severity. There wasno need for medical treatment during vasovagal episodes and nopost-proceduralsequelae occurred. Vasovagal reactions, whichcanresultfromoverstimulationofthenerve,maybe eas-ily avoided [31,32]. According to ourdata, vasovagal reactions canbeexpectedinapproximately0.16%of patients,onein638 examinations. These figures compare favorably with results of routine colonoscopy practice, where vasovagal reactions have beenreportedin 16%of cases[33–37]. On theotherhand,our estimate is considerably higher than those reported in prior studiesonCTCcomplications.[18,37].Colonicperforationisthe mostdreadful complicationof a colorectaldiagnostic examina-tion.In our survey cohort, theincidence ofcolonic perforation was 0.02%, one in 5731 CTC examinations, though. Only 3 of the 7 perforated patients eventually needed post-CTC surgery. Whencomparingourdata withtheendoscopicseries, the per-forationrateatcolonoscopy,whetherdiagnosticortherapeutic, wouldappear tobehigher thanthat ofCTC.The reported per-foration rates for colonoscopy range from one case in 3115 procedures (0.032%) to one case in 510 procedures (0.196%) [17,39–44].Thus,our0.02%estimateofpost-CTcolonography per-forations imparts a significantly more favorable profilefor CTC comparedtocolonoscopy. Inourseries,nosymptomatic perfo-rations wereidentified. Estimatesof perforation rate following colonoscopy were based only on those patients in whom the colonoscopistwasawareof theevent orsubsequentsymptoms alertedclinicianstothiscomplicationfollowingtheprocedure.So itistobeexpectedthatasymptomaticperforationsare underre-portedat colonoscopy.Literature reports that upto50% ofthe colonoscopy-relatedperforations are not recognizedat time of colonoscopy[18].Therefore,ourstudysupportspreviousevidence thattheriskofsymptomatic perforationsislower forCTCthan colonoscopy[20,22].Nodeathswererecordedinourseries. Mor-talityfromcolonoscopyhasbeenreportedtobeashighas0.07% (1deathevery1500colonoscopies)[41]thoughtherateismuch lowerwhencolonoscopyisusedforscreeningpurposes[42].Our dataonperforationsissimilartothatreportedbytheAmerican sur-vey[20,21]andfavorablycompareswiththedatafromthesurvey performedinUKandIsrael[18,19].

Allsevenperforations in our survey occurredin CTC exam-inations performed using air as gaseous medium in manually controlledinsufflations.Accordingtotheliterature,theuseofan automated low-pressureCO2 deliveryreduces perforationrate,

havingthepossibilitytocontrolgaspressureandvolumeduring theinflation,and tomaintainbothofthemconstantduringthe procedure.Inflatingthecolonmanuallywithairdoesnotgivethis opportunityandcouldgenerateunknown(possiblyhigh)pressure andvolumevaluesthatcanonlybeestimatedandpotentially harm-ful[22].However,giventhattheoccurrenceofperforationatCTCis arareevent,wewereunabletodemonstrateacausalrelationship betweenmanualinsufflation,asopposedtoautomaticinsufflation, andperforation.Rectaltubesarerigidcatheterswithlargecaliber areassociatedtoamajorriskofcomplicationsduetothefactthatits rigidityhasthepotentialtobreachanormalrectalwallifforcefully

inserted.Inoursurveytheuseofrigidcatheterswaslimitedto21% examsand,notably,theyhavebeenusedmuchmorefrequently until2004.Inourpopulation3perforationsoccurredinpatients previouslydistendedwiththeuseofarigidcatheter,but,as pre-viouslystated,theseeventsoccurredintheperiodrangingfrom 2000and2003.Toourknowledge,since2005noCTCexaminations havebeenperformedbyusingthattypeofcatheter,thusdecreasing dramaticallythenumberofperforationsoccurred.Hence,our esti-mateofperforationrateamongpatientsdistendedwithaflexible catheter(0.012%;1every7980examinations)maybeamore rele-vantmetricreflectingwhatcouldbeexpectedinthefuture.

Other important risk factors for perforations are recent colonoscopy and presence of comorbidities. Previous recent colonoscopy, especially with polypectomy, can damage colonic wall,makingperforationeasierattimeofinsufflation.Currently, there isalmosttotal consensusamong expertsthatCTCshould bedelayedifapolypectomyand/orbiopsyhasrecentlybeen per-formed[22,45].However,thereislittleevidenceaboutasafe inter-valbetweencolonoscopyandCTC[45].Therefore,thepossibilityof aperforationfollowingarecentopticalcolonoscopy,mustbe care-fullyinvestigatedbeforeCTCprocedure[22,45,46].Inourstudy, 2perforationsoccurredinpatientsundergoingasame-dayoptical colonoscopy.Ofnote,inthesetwopatientstheusualcolonic disten-sionwasperformed,alowdosescoutwasobtainedbutnoCT low-doseacquisitionperformed,makingitimpossibletounderstand therealcauseofperforation.Inotherthreecasesofperforation, patientsunderwentcolonoscopywithin2weeksbeforeCTC.Hough etal. describedtwo casesof perforationon262patients(0.8%) undergoingCTCaftercolonoscopyand thenstudiedwitha low doseCTscanbeforecolonicinflation[47].Inourseries,three(42%) perforations occurred in patients with diverticulosis; no other comorbiditiessuchascarcinomaorleftinguinalherniacontaining sigmoidwerenoted[19,22].Giventhehigherpercentageof diver-ticulosisinthegeneralpopulation,itisimportanttoproceedwith cautioninpatientswithprovenorsuspecteddiverticulardisease.

AspreviouslyreportedinliteraturebyAtallaetal.,eveninour surveynocorrelationbetweentheincidenceofperforationand theinstitutional experience wasobserved [46].This event was demonstrated bythefact that5 out of7 perforations occurred intwocenterswithalargenumberofmonthlyCTCexamination performed.

Ourstudyhassomelimitations.First,itmustbeemphasizedthat thedataofthissurveyaresubjecttoalltheerrorsinherentinany kindof retrospectivedatacollection.Furthermore,thesurveyed centerswerenotarandomsampleofallItalianCTCcentersbut arepresentativesampleofthosepracticingCTCafterappropriate training.Ourdata,thus,representtheCTCpracticeat“well-trained” centersandthislimitsthegeneralizabilitytocommunitypractice. However,trainingisrecognizedasakeyissuebeforeCTCservice implementation[23]and theever-increasingexperienceofCTC serviceswillprobablyfurtherreducetheincidenceof complica-tions.Therefore,webelievethatourresultsmayreflectwhatis achievableincommunitycare,assumingareasonablelevelofbasic training.Nonetheless,thissurveyprovidesinformationthatdoes notexistatpresentinItaly.Anotherpossiblelimitationwasthe exclusionofprivatehospitals.Itisdifficulttopredicttheimpact ofthis bias.Ifpatientswithlesssevere illness,and lowchance ofcomplications,aremorelikelytobetreatedinprivate hospi-talsandthesedatawerenotreported,thenthatwouldlikelylead tooverestimationofthecomplicationsrate.Ifthisisthecase,the smallpercentageofperforationsinourserieshasmadeevenmore relevantourpositivefindingsforCTCsafety.Oursurveyisbased onself-reportedpracticeandis,therefore,subjecttorecallbias. Thereis a naturaldisincentivetoreport complicationsthat are managedsimplyandimmediately[38].Thus,manyminor com-plicationssuchasprolongedcramping ornausea mayhavenot

beenrecorded.Furthermore,studyresultsmayhavepartiallybeen affectedbydifferentcriteria usedbythevarious Institutionsin reportingcomplications.Datalimitationsprecludedanextensive evaluationofthecause-effectrelationshipbetweenfactorssuch astheexperienceoftheindividualwhoperformstheinsufflation, comorbiditiesand recent colonoscopyand perforations. Specifi-cally,wewereunabletoretrospectively determinetherates of thesepotentiallyriskfactorsinthelargepopulationinwhich per-forationsdidnotoccur.Alsoacausalrelationshipbetweencolon distensionandspasmolyticsusecouldnotbeinferred.However, thestudyofriskfactoranalysiswasnotthemainpurposeofthis surveyandfurtherprospectivetrialswillbeneededtoreach cause-effectconclusions.Finally,atthetimeofdatacollection,regional governmentsdidnotallowNationalHealthServicereimbursement ofCTCasascreeningtest.Thus,itispossiblethatthissurveyreflects symptomaticpopulationsonly.

Insummary,oursurveyhasshownthatcolonicperforationrate ofCTCencounteredinItalianhospitalsarecomparablewith else-whereintheworldandeventsoccurregardlessoftheexperience leveloftheradiologycenters.Whileseverecomplicationsarevery uncommon,adverseeventsofmildsignificance,suchas vasova-galreactions,mayoccurmorefrequently.Althoughtheperforation rateatCTCisverysmall,itmaynotbenegligiblewhencompared withtheriskofdiagnosticcolonoscopy.

Conflictofintereststatement

Noconflictofinterestforalltheauthors. AppendixA. Participatinginvestigators

B.Barbaro,MD,L.Bonomo,MD:DepartmentofRadiology, Uni-versity“CattolicadelSacroCuore”,Rome,Italy;F.Sandrucci,MD: DepartmentofRadiology,“SanCamillo”Hospital,Rome,Italy;M.C. Cassinis,MD,G.Gandini,MD:DepartmentofRadiology,University ofTurin,Italy;N.Flor,MD,G.Cornalba,MD:Departmentof Radi-ology,“SanPaolo”Hospital,Milano,Italy;R.Asnaghi,MD:Istituto ScientificoediRiabilitazione,DepartmentofRadiology,Veruno, Italy; A. Caprotti, MD: Casadi Cura SanPio X, RadiologyUnit, Milano,Italy;F.Coppola,MD,R.Golfieri,MD:Sant’OrsolaMalpighi, Hospital,Departmentof Radiology,Bologna,Italy;C. Bartolozzi, MD:Universityof Pisa,Diagnosticand InterventionalRadiology Pisa, Italy;R. Fiori, MD, G. Simonetti, MD: University of Rome “Tor Vergata”,Department of Radiology,Rome,Italy; R.Rizzati, MD,G.BeneaG,MD:OspedaledelDelta,Departmentof Radiol-ogyLagosanto,Italy;S.Venturini:CRO,DepartmentofRadiology Aviano,Italy.

AppendixB. Supplementarydata

Supplementarymaterial related tothis article found, in the onlineversion,athttp://dx.doi.org/10.1016/j.dld.2013.02.020. References

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