This document provides an overview of contrast media used in various imaging modalities. It defines contrast media as substances used to improve visualization of organs and tissues. The main types discussed are iodinated contrast agents for CT and angiography, barium sulfate for fluoroscopy, gadolinium-based and iron-based agents for MRI, and microbubble suspensions for ultrasound. Adverse reactions, administration routes, properties and indications for use are summarized for each contrast type.

1. CONTRASTMEDIA
Presenter:DrJoanRachealNahwera
U/21030008/MMED

2. CONTENT
 Definition
 Typesandclassificationofcontrastmedia
 Propertiesofdifferenttypesofcontrastmedia
 Usesof differenttypesof contrastmedia
 Adversereactionstocontrastmedia
 Managementof theaboveadverseeffects
 Drugsthatareonemergencytraysduringcontraststudies
 Contraindicationsofcontrastmedia.

3. INTRODUCTION
 AsX-rayspass throughthebodytheyareeitherscattered,attenuated
ortheypassthrough.
 Note:DifferenttissueswithinthebodyattenuatethebeamofX-rays
todifferentdegrees.
 Thedegreeofattenuationofanx-raybeambyanelementiscomplex,
 Butoneofthemajorvariablesisthenumberofelectronsinthepathof
thebeamwithwhichitcaninteract.

4.  Thenumber ofelectronsinthepathofthebeamisdependent upon
threefactors
1. Thethicknessofthesubstancebeingstudied
2. Itsdensity
3. Thenumber ofelectronsperatomoftheelement(atomicnumber)

5.  Iftwoorganshavesimilardensitiesandsimilaraverageatomic
numbers,itisnotpossibletodistinguishthemonaradiographbecause
nonaturalcontrastexists.
 Forexample:itisnotpossibletoidentifybloodvesselswithinan
organortodemonstratetheinternalstructuresof akidneywithout
alteringoneofthefactorsmentionedearlier.(densityofanorganand
atomicnumber)

6.  Contrastmediumisanysubstanceintroducedintothebodyinorderto
makeanorgan,orsurfaceofanorganorthematerialswithinthe
lumenofanorganvisibleonimaging.
 OR Contrastmediaareagroupof chemicalagentsdevelopedtoaidin
thecharacterizationofpathologybyimprovingthecontrastresolution
ofanimagingmodality

8. •RADIOGRAPHIC CONTRAST MEDIA ARE DIVIDED INTO POSITIVE AND NEGATIVE
CONTRAST AGENTS.
 Thepositivecontrastmedia
attenuate X-raysmorethando
thebodysofttissuesandcanbe
dividedintowatersolubleiodine
agentsandnonwatersoluble
bariumagents.  Negativecontrastmedia
attenuate X-rayslessthando
thebodysofttissues.Nonegative
contrastmediaarecommercially
available.(airandgas)

9. IODINATEDCONTRASTMEDIA
 Iodinatedcontrastmediaarecontrastagentsthatcontainiodineatomsused
forx-ray-basedimagingmodalitiessuchascomputedtomography(CT).
 Theycanalsobeusedinfluoroscopy,angiographyandvenography,andeven
occasionally,plainradiography.
 Althoughtheintravenousrouteof administrationismostcommon,theyare
alsoadministeredbymanyotherroutes,includinggastrointestinal(oral,
rectal),cystourethral,vaginal,intraosseous,etc.

10.  Physics
 The ability todistinguishbetweentissuesof different x-ray attenuation(image contrast)
dependsupon twotypesof interactions betweenphotons and matter:Compton scatteringand
photoelectric absorption.
 Boththeseinteractions dependuponphysical density,butthelatteralsodependsuponatomic
numberof thematter.
 Asiodine hasa highatomic number, 53,comparedtomosttissuesinthebody,the
administration ofiodinated material producesimagecontrast duetodifferential photoelectric
absorption.
 Iodine hasaparticular advantageasacontrastagentbecausethek-shellbinding energy (k-
edge)is 33.2keV,similar to theaverageenergyof x-raysusedindiagnosticradiography .When
theincidentx-ray energyiscloser tothek-edgeof theatomit encounters,photoelectric
absorption ismore likely tooccur.
 Differences inphotoelectric absorption acrossdifferent x-ray energiesisharnessedindual-
energyCT, inwhichpatientsarescannedwithtwodifferent x-ray spectra.
 Materialdecomposition techniquesallows thecreationof virtual imagesinwhichiodine is
preferentially increasedinintensity(iodine map)orremoved altogether (virtual non-contrast),
whichcanhold additional diagnostic value.

11.  Contraindications
1. Documentedpreviousseverereactiontoiodinatedcontrastmedia,
includinganaphylaxis,angioedemaandbronchospasm.
2. Milderpreviousreactionstoiodinatedcontrastmedia.
3. Renalimpairment/failure
4. Riskfactorsforallergicreactiontoiodinatedcontrastmedia
5. Myastheniagravis:controversialandremainsinsomeproductinsertsand
guidelines

12. Water-solubleiodinatedcontrastmediacanbeclassifiedbyosmolality

13.  Highosmolalitycontrastmedia
 High osmolality contrast media(HOCM) are approximately five toeighttimes
theosmolality of serum.
 Ingeneral, HOCM are ionic compounds thatinclude abenzenering withthree
iodine atomsandasidechaincontaining acarboxylicacid (-COOH) group.
 Asthefirst generation of iodinated contrastagents,HOCM wereassociated
withhighratesof adverseeventsandfell out offavor inthe1990sfor
intravascular andintrathecal purposes.
 HOCM remainusedfor gastrointestinal andcystourethral
administration, including thefollowing agents:
 Diatrizoate sodium/meglumine(Gastrografin, MD-Gastroview, Cystografin)
 Iothalamate sodium/meglumine (Conray, Cysto-Conray)

14.  Lowosmolalitycontrastmedia
 Lowosmolalitycontrastmedia(LOCM)arelessthanthreetimestheosmolalityofhumanserumand
preferred forintravascularandintrathecaladministration.
 ModernLOCMaregenerally,butnotalways,nonionicmonomerscomposedof tri-iodinatedbenzene
ringswithvarioussidechainsthatcontainpolaralcohol(-OH)groupsthatmakethemwater-soluble
 LOCMincurrentuseincludethefollowing:
1. iopamidol(Isovue)
2. iohexol (Omnipaque)
3. iopromide(Ultravist)
4. ioversol (Optiray)
5. ioxilan(Oxilan)
 TheLOCMcategoryalsoincludesiso-osmolalcontrastmedia(IOCM),whichareapproximatelythesame
osmolalityasserum.
 TheonlyIOCMincurrentuseisanon-ionicdimer,whichiscomposedoftwocovalentlyboundtri-
iodinatedbenzenerings:
 iodixanol(Visipaque)
 Thedimerstructureof iodixanolfits ahigherconcentrationofiodine atomsperosmole,permitting
diagnosticlevelsofcontrastopacificationatlesstoxicosmolality.
 Non-ionicLOCMareavailableinvaryingconcentrationsrangingfrom240to400mgiodine/mL.
 Higherconcentrationformulationsproduceagreaterpeakofenhancement(measuredinHounsfield
units)butarealsomoreviscous.

15.  Water-insoluble
 Water-insolubleiodinatedcontrastmediahavelimiteduses.
 Theonlycurrentlyapprovedagentisethiodizedpoppyseed oil
(Lipiodol), whichisusedfor embolo/sclerotherapyand
hysterosalpingography.
 Ahistorically-popularbutnowdiscontinuedwater-insolubleiodinated
agentwasiophendylate(Pantopaque/Myodil), whichwasusedfor
myelography.

16. Administration
Intravenous
 Contrast injectedintravenously isoften mechanicalviaacomputerizedpressureinjector.
 The AmericanCollege of Radiology recommendsacannula of20-gauge orlarger for the
mechanicalinjection of intravenous contrastfor anyinjections thatrequire aflow rate higher
than3mL/s.
 The prewarming of contrastagents,particular onesof higherconcentration (370 mg/mL)will
lower thechancesof contrastextravasation.
 Intraosseous
 Inthecontext ofthecritically ill patientwhere intravenous accessis notpossible, iodinated
contrastcanbeadministeredvia anintraosseous injection.
 Pressureratesmustbehighduetothe intramedullary pressurewithinthebone.
 According totheACR Committee onDrugsandContrast Media, therearenoreported
complications of intraosseous injections at5 mL/s.
 The humerusisthemostcommonly acceptedsiteof injection .

17. BARIUM SULFATE (BASO4
 Bariumsulfate(BaSO4),often just called bariuminradiology parlance, is anionic salt
of barium(Ba) ametallic chemicalelementwith atomicnumber56.
 Bariumsulfate forms thebasisfor arangeof contrastmediausedinfluoroscopic
examinations ofthegastrointestinal tract.
 Unlike barium and manyof itsother salts,bariumsulfate isinsoluble inwaterand
therefore verylittle of thetoxicbariummetal isabsorbedinto thebody.
 Indications
 Itisthepreferential contrastagentfor gastrointestinal (GI) fluoroscopic
examinations dueto:
1. highattenuationofx-rays
2. lackof absorption from thegutintothebody
3. lackof toxicity (in thegut)
4. Itcanalso befound insomeoral contrastpreparations usedfor CT.

18.  Bariumcanbemixedintohigh-density orlow-density suspensions.
 Bothsuspensionstypically attenuatex-rays morethanwater-soluble
contrast.
 High-density bariumis preferred over water-soluble contrast for fine-detail
evaluation ofthegastrointestinal system(e.g.evaluation for early changes
from Crohn disease).
 Suspensionscreatedfor CT useare verylow density.
 Dueto itsinsolubility inwater,bariumsulfate contrastmediaaresupplied as
fine particles of thebariumsulfate suspendedinwater.
 Often artificial flavourings areaddedtomakethemixturemore palatable.
 Itsallergy profile is favourable withveryfew reported reactions.
 Historically, allergy wasmore commonwhenexcipients,suchaschocolate,
wereused.

19.  Contraindications
 Known orstronglysuspectedgastrointestinalperforation
 maybeused inevaluationfor possible esophageal perforations.
 largevolumeaspirationrisk
 priorallergicreaction(rare)
 left-sidedcolonicobstruction(relativecontraindication)
 ifthebariumcannotexitthecolon, ithas thepotentialtobecome
inspissated andveryhard, leading toaquiteproblematic constipation

20.  Complications
 Bariumcontrastagentsmaycauseaperitonitisiftheyleakintothe
peritonealspace.Ifbowelperforation issuspected,water-soluble
contrastisgenerallypreferred..
 Bariumhasthepotentialtoplugthedistalairways,diminishingthe
capacityforgasexchange,andbariumaspirationmayrarelybefatal
 Bariummigrationintothebloodstream,knownasintravasationisa
seriousandrarecomplication,withthepotentialtocausefatalend-
organemboliespeciallypulmonary,althoughitisincrediblyrareifthe
contrastisusedappropriately.

21.  MRContrastMedia
 Magneticresonance(MR) imagingcontrastagentscontain
paramagneticorsuperparamagneticmetalionswhichaffecttheMR
signalpropertiesofthesurroundingtissues.
 Theyareusedtoenhancecontrast,tocharacterizelesionsandto
evaluateperfusionandflow-relatedabnormalities.
 Theycanalsoprovidefunctionalandmorphologicalinformation.

22. PARAMAGNETIC CONTRAST AGENTS
 ParamagneticcontrastagentsaremainlypositiveenhancerswhichreducetheT1andT2
relaxationtimesandincreasetissuesignal
 Themostwidelyusedparamagneticcontrastagentsarenon-specificextracellular
gadoliniumchelates.
 Theiractiveconstituentisgadolinium,aparamagneticmetalinthelanthanideseries,
whichischaracterizedbyahighmagneticmomentandarelativelyslowelectronic
relaxationtime.
 Non-specificextracellulargadoliniumchelatescanbeclassifiedbytheirchemical
structure,macrocyclicorlinear,andbywhethertheyareionicornonionic.
 Theyareexcretedviathekidneys.
 Paramagneticcontrastagentsalsoincludeliverspecificgadoliniumbasedagents
(gadobenatedimeglumine,Gd-BOPTAandgadoxetate,Gd-EOBDTPA)andmanganese-
basedpreparations[manganesechelate(mangafodipirtrisodium)andfreemanganese
combinedwithvitaminsandaminoacids(topromotetheuptake)fororalintake].
 Thesehepatobiliarycontrastagentsaretakenupbyhepatocytesandthenthereis
variablebiliaryexcretion.
 Thegadoliniumbasedliverspecificcontrastmediaarealsoexcretedbythekidney
intensityon T1-weightedMRimages.

23. SUPERPARAMAGNETIC CONTRAST AGENTS
 Superparamagneticcontrastagentsincludesuperparamagneticiron
oxides(SPIOs) andultrasmallsuperparamagneticironoxides(USPIOs).
 TwopreparationsofSPIOsareavailable:ferumoxidesandferucarbotran.
 Theseparticulateagentsarecomposedofanironoxidecore,3–5mmin
diameter,coveredbylowmolecularweightdextranforferumoxidesand
bycarbodextranforferucarbotran.
 SPIOsareapprovedforliverimagingandUSPIOs areunderconsideration
forMR lymphography.
 Afterinjection,SPIOandUSPIOparticlesaremetabolisedintoasoluble,
nonsuperparamagneticformofiron.
 Ironisincorporatedintothebodypoolofiron(e.g.ferritin,hemosiderin
andhemoglobin)withinafewdays

24. ULTRASOUND CONTRAST MEDIA
 Ultrasoundcontrastagentsproducetheireffect byincreasedback-scatteringof
soundcomparedtothatfromblood,otherfluidsandmosttissues.
 Ongreyscaleimagesmicrobubblecontrastagentschangegreyanddarkareastoa
brightertone,whenthecontrastenters influidorblood.
 ThespectralDopplerintensityisalsoincreased,withabrighterspectralwaveform
displayedandastrongersoundheard.
 UsingcolorDopplertechnique,ultrasoundcontrastagentsenhancethefrequencyor
thepowerintensitygivingrisetostrongercolorencoding.
 ThelevelofenhancementoftheDopplersignalsmaybeintheorderofupto30dB.
 UltrasoundcontrastagentscanbeusedtoenhanceDopplersignalsfrommostmain
arteries andveins.
 Theymaybeusefulfor imagingsolidorgans,e.g.liver,kidney,breast,prostateand
uterus.
 Theycanalsobeusedtoenhancecavitiese.g.bladder,ureters, Fallopiantubes,
abscesses.

25. CLASSIFICATION
 Ultrasoundcontrastagentscanbedividedintofivedifferentclasses:
 Nonencapsulatedgasmicrobubbles(e.g. agitatedor sonicated)
 stabilisedgasmicrobubbles(e.g. withsugarparticles),
 encapsulatedgasmicrobubbles(e.g. byprotein,liposomesorin
polymers)
 microparticlesuspensionsoremulsions[perfluorooctylbromide
(PFOB), phase-shift]
 gastrointestinal(for ingestion).
 Productsarenotcommerciallyavailablefromallclasses.

26.  Ultrasound contrast agents(USCA) canalso beclassified basedon their
pharmacokinetic properties andefficacy:
 Non-transpulmonary USCAs whichdo notpassthecapillary bedof thelungs
following aperipheralintravenous injection, showonB-mode only inthe
rightventricle, andhaveashort duration effect,
 transpulmonaryblood pool USCAs withashort half-life (<5 minafter an
intravenous bolus injection), whichproduce low signalsusing harmonic
imaging atlow acousticpower,
 transpulmonaryblood pool USCAs withalonger half-life (>5 minafter an
intravenous bolus injection), whichproduce high signalsusingharmonic
imaging atlow acousticpower,
 transpulmonary USCAs withaspecificliver andspleenphasewhichcanbe
shortor long-lived. Theylodge inthesmallvesselsof theliverorspleen, or
aretakenupbyeither thereticuloendothelial systemor bythehepatocytes.

27.  Someultrasoundcontrastagentsonorclosetothemarketinvarious
partsoftheworld(officiallyavailabledataperApril,2005)
Productname Someproperties
DefinityTM(DMP115) Fluorocarbongas in liposomes
SonoVue®(BR1) Sulphurhexafluoridegas inpolymerwith
phospholipid
OptisonTM (FS069) Octafluoropropane-filledalbuminmicrospheres
SonazoidTM (NC100100) Perfluorinatedgas-containingmicrobubbles
Levovist® (SHU508A) Galactose-based,palmitic acid stabilised air-bubbles

28. METHODSOFCATEGORIZINGCONTRASTREACTIONS
 Therearetwousefulwaystoapproachcontrastreactions.
 Oneistocategorizethemaccordingtotheirseverity.Thismethodhas
immediateclinicalrelevancewhenreactionsoccurandprovidesa
frameworkfordetermininganappropriatecourseoftreatment.
 Theotherapproachistoanalyzethemaccordingtothetypeofadverse
reaction.Thisisimportanttounderstandthemechanismsofreactions.

29. SEVERITY(THE AMERICAN COLLEGE OF RADIOLOGY HAS DIVIDED ADVERSE REACTIONS TO
CONTRAST AGENTS INTO THE FOLLOWING CATEGORIES)
 Mild
 Signs andsymptomsappearself-limitedwithoutevidenceof
progression
 Nausea,vomiting Alteredtaste SweatsCough
Itching Rash,hivesWarmth(heat) Pallor
Nasalstuffiness
Headache Flushing Swelling:eyes,faceDizziness
Chills AnxietyShaking
 Treatment:Observationandreassurance.Usuallynointerventionor
medicationisrequired;however,thesereactionsmayprogressintoa
moreseverecategory

30.  Moderate
 Reactionswhichrequiretreatmentbutarenotimmediatelylife-
threatening
 Tachycardia/bradycardia Hypotension Bronchospasm,wheezing
Hypertension Dyspnea LaryngealedemaPronounced
cutaneousreaction Pulmonaryedema
 Treatment:Prompttreatmentwithcloseobservation

31.  Severe
 Life-threateningwithmoreseveresignsorsymptomsincluding:
 Laryngealedema Profoundhypotension
Unresponsiveness(severeorprogressive) Convulsions
Cardiopulmonaryarrest Clinicallymanifestarrhythmias
 Treatment:Immediatetreatment.Usuallyrequireshospitalization

32.  Fortunately,mostreactionsareclassifiedasmild.
 Withinthiscategory,itching,flushing,hives,nasalcongestion,and
swellingabouttheeyesandfacearecommon.
 Nauseaandvomitinghavebecomelesscommonwiththeuseoflow
osmolarandiso-osmolaragents.
 Amongthemoderatereactions,bronchospasmandlaryngealedema
areencounteredmostfrequently;patientsmustalsobemonitored
carefullyforchangesincardiacrateandbloodpressure.
 Severereactions,whileinfrequent,canrapidlyescalatetoalife-
threateningsituation.

33. DELAYED CONTRAST REACTIONS
 Delayedcontrastreactionscanoccuranywherefrom3hoursto7days
followingtheadministrationofcontrast.
 Itisstillimportantforanyoneadministeringintravenouscontrastmediatobe
awareofdelayedreactions.
 Withtheexceptionofcontrast-inducednephropathy,themorecommon
reactionsincludea
 cutaneousxanthem, pruritiswithouturticaria, nausea,vomiting,
drowsiness,andheadache.
 Whilecardiopulmonaryarresthasbeenreported,itisprobablynotrelatedto
newercontrastagents.
 Cutaneousreactionsarethemostfrequentformofdelayedcontrastreaction
withareportedincidenceof0.5-9%.

34.  Cutaneous reactions varyinsizeand presentationbutare usually pruritic.
For themostpart,thesereactionsare self-limited and symptomscanbe
treatedwithcorticosteroid creams.
 Rarecasesmayprogresstobecomesevere,someresemblingStevens-
Johnsonsyndromeora cutaneousvasculitis.
 Consultation withadermatologist isappropriate for delayedcutaneous
reactions.
 Delayedcutaneous reactionsare morecommon inpatientswhohavehada
previous contrastreaction andinthose whohavebeentreatedwithinthe
past2years,or arecurrently beingtreated withinterleukin-2 (IL-2).
 While theexactmechanismof thedelayedreactionisunknown,theycan
recurif thesamecontrastmediumisadministeredagain.Therefore, itis
possible thatthesedelayed reactions areT-cell mediated.Assuch,
prophylaxis withoral corticosteroids maynot beuseful

35. MECHANIIMSOFSOMEADVERSEREACTIONS
• Anaphylactoid
• Nonanaphylactoid Chemotoxic–organ-specific
Nephrotoxicity
Cardiovasculartoxicity
Neurotoxicity

36.  ANAPHYLACTOIDREACTIONSPathophysiology
 Anaphylactic reactions areeventsinitiated whenan allergen and IgE combine
toinducemastcells toreleasechemicalmediators.
 Mastcellsoriginate from bone marrow precursors anddevelop intheorgans in
whichtheycometoreside.
 Principal locations aretheskin, respiratory tract,GI tract,andblood vessels.
 Allergen-specific IgE is boundon thesurface ofmastcells.
 The allergen-IgE complexactivatesthemastcellandinducesit torelease
histamineaswell asother mediators.
 Histaminebindsto specificreceptorsites.H1receptorsarefound inendothelial
andsmoothmusclecellsandinthecentral nervoussystem.
 H2receptors areingastric parietal cells andininflammatory cells.
 The natureof ananaphylacticreaction dependsupon thelocation whereit
occurs.
 Intheskin, vasodilatation producesurticaria anderythema.
 Inmucosa,vasodilatation produces nasalcongestion and laryngeal edema.
 Intherespiratory tract,smooth musclecontraction produces bronchospasm.In
peripheral vessels,vasodilatation produceshypotensionandshock.
 Gastrointestinal reactions include nausea,vomiting, diarrhea, andcramps.

37.  Anaphylactoid reactions areidentical toanaphylacticreactions intheir
manifestations,buttheyarenot initiated byanallergen-IgE complex.
 Acutecontrastreactions areincluded inthisgroup.
 The distinctionbetweenanaphylacticandanaphylactoid reactions issubtle,butit
hascertainimportant implications for theuseofiodinated contrast:
1) Areaction canoccur eventhefirst timecontrastisadministered.
2) The severityof areactionisnotdose-related; therefore atestdose isof novalue.
3) The occurrenceof acontrastreaction doesnot necessarilymeanthatitwill
occur again(although therisk isgreaterthatitmay).
4) Even thoughthecirculating contrastissystemic,thenatureof theresponseis
variable.
5) More thanone typeof reaction mayoccur simultaneously.
 Aswithanaphylacticreactions, certain riskfactors makepatientsmore
susceptibleto iodinated contrast(anaphylactoid) reactions
 : Allergic asthma Drugallergies Food allergies Prior reactions tocontrast

38.  TreatmentofAnaphylactoidReactions
 Anaphylactoidreactionsusuallyoccursoonaftercontrastis
administered.
 Theyarevariableindurationandseverity.
 Theymayoccurabruptlyandprogressrapidly.
 Successfulmanagementoftheseeventsdependsuponearly
recognition,promptandaccurateassessment,andpreparedness.
Becausesignificantreactionsdonotoccuroften,itisnecessaryto
reviewthemfrequentlyenoughsothatbasicknowledgeand
managementprioritiesremaincurrentandfresh.
 Itisofutmostimportancethatmedicationsandequipmentbepromptly
available.

39. AN EMERGENCY BOX OR CART
 shouldbeintheimmediatevicinity.
 itshouldbesealed(notlocked)sothatitwillbeintactwhenneeded.
 Itmustbeperiodicallyinspected(andrecordedandsignedonacheck-offlog)to
insurethatitisfullystockedandthatnoneofitscontentshaveexpired
 Alistofmedications,indications,anddirectionsfortheiruseandalistof
emergencyphonenumbersshouldbeprominentlydisplayed.
 Astethoscopeandbloodpressurecuffofsufficientqualityforreliableclinical
useshouldbeincluded.
 ThereshouldbeabagofisotonicIVsolution(normalsalineorRinger’ssolution)
withIVtubing.
 Anappropriateselectionofneedlesandsyringesandeverythingelseneededto
drawupmedicationsorstartadditionalIVsshouldbeavailable.
 AnAmbubag™withaproperassortmentofmasks,laryngoscopeswith
endotrachealtubes,andairwaysshouldbeincluded.
 Thereshouldbeaflashlightandtonguedepressors
 Anoxygentankandtubingshouldbecloseathand
 Aclipboardwithpaperforflowsheetsisveryhelpful.
 Allpoliciesandproceduresshouldbedatedandperiodicallyreviewed

40.  Whensummonedtoassessapatientwhomaybehavinganadversereaction, you
mustbeable toactquickly, purposefully, andeffectively.
1. Ascertainfrom thetechnologist ornursewhattheproblem is. Speaktothe
patienttoobtain additional information anddeterminehow he/sheresponds.
2. Consult information onpertinentmedicalhistory (this should beobtained before
thecontrastinfusion isstarted).
3. Immediatelystop thecontrast infusion, hook up isotonic IVfluids, andopen theIV
wide.
4. Obtain vitalsigns.
5. Check theairwayand breathing.
6. Check skincolor, temperature,and dryness.
7. Donot hesitatetoadminister oxygenbymask(6–10 liters/min)
8. elevatethepatient’slegsfor hypotension, orstartadditional Ivsor other drugs
asappropriate.
9. Reassessthepatient,andmakeeffective decisions ascircumstanceschange.
10. Those assistingshould executetheirdutiesquietly, minimizinganxiety-
provoking conversation.

41. MEDICATIONS
 AlbuterolInhaler:
 ABeta-2agonistthatcauses
bronchodilatationandrelieves
bronchospasmthatmayoccur
withasthmaorasareactionto
contrast.
 ADULT DOSE: 2puffstostartMay
needtoberepeated
 PEDIATRICDOSE: 2puffs OR2.5
mgin3mLnormalsalinefor
nebulizerifrespiratory
therapistispresent

42.  Atropine
 Aparasympatholyticagentused
totreatbradycardiathatresults
fromavasovagalreaction
(characterizedbyhypotension
andbradycardia
 Theminimumadultdoseis0.6
mg, sinceasmalleramountcan
haveaparadoxicalreverse
effect.DOSE:0.6–1.0 mgIVslowly
Maximumdose=2mg
 PEDIATRICDOSE:0.02mg/kg
 IVMaximumdose=1mg
Minimumdose=0.1 mg

43. :Diphenhydramine
 Anantihistamine whichis anH-1
receptorsiteblocker.
 Itshould beusedonly totreatmild
urticaria, whichislikely toresolve on
itsown,andwhere itisdeemed
desirable toprovide symptomatic
relief bypreventingfurther reactions.
 Should not beusedfor severe
urticaria orother more significant
reactions
 ADULT DOSE: 25–50 mgIV orIM
Caution: Causesdrowsiness. Patient
should not drive oroperate
machineryfor 4-6 hours.
 PEDIATRIC DOSE :1mg/kg

44.  Clonidine:
 Adrugusedtotreata
hypertensivecrisis.
 DOSE: 200mcg(0.2 mg).
 Bite,chew,andswallow

45.  Epinephrine:
 Adrug whichisabasicsympathetic
agonist
 Asanalpha agonist,epinephrine is
usedtotreatsevereurticaria, facial
edema,andlaryngeal edema.
 Asabeta-2agonist,itmaybeneeded
totreatbronchospasm. Itmustbe
usedwithcautioninpatientswith
cardiacdiseaseandhypertension
 DOSE: Subcutaneous:1:1,000(1
mg/mL)0.1–0.3mL(0.1 –0.3 mg)
 DOSE: Intravenous: 1:10,000(0.1
mg/mL)1mLIVslowly every3–5
minutesMayrepeat upto1mg
maximum

46.  Diazepam:
 Abenzodiazepineusedtotreat
seizures.
 ADULT DOSE: 5–10mgIVpush
Maximumdose:30mg
 PEDIATRICDOSE:0.2–0.3 mg/kg
slowIVpushperdose
 Mayrepeatin5-10minutes

47.  Nitroglycerin:
 Avasodilatorusedtotreat
acuteangina.
 DOSE: 0.4mgsublingual
 Mayberepeatedeveryafter 5
minutesforatotalof3doses

48. PREMEDICATION
 Overall,patientswhoareatincreasedriskforananaphylactoid
reactionbenefitfrompremedication.Suchpatientsincludethosewith
asthma,allergies,orahistoryofapriormoderateorseverereactionto
contrast.
 Itshouldbenoted,however,thatpremedicationisnotafail-safe
guaranteethataniodinatedcontrast-enhancedexaminationwillbe
performedwithoutcomplication.
1. Methylprednisolone:DOSE: 32mgbymouth12and2hours before
contrast.
2. DiphenhydramineDOSE: a.50mgIMorPO1hourbeforecontrast,ORb.
50mg(or25mgperheight/weightindication)IV15–20minutes

49. NONANAPHYLACTOID REACTIONS
 CHEMOTOXICREACTIONS
•Causedbytoxicitytocontrastmediummoleculeasawhole,andis
moreoftenduetocations,particularly-Na.
 Theymaybecardiac,neurological,renal.

50. CONTRASTINDUCEDNEPHROTOXICITY
 Nephrotoxicityofcontrastmediaisdueto
decreasedrenalperfusion(lowBP, peripheralvasodilatation).
glomerularinjury–manifestsasproteinuria.
Tubularinjury-duetoosmolality,chemotoxicity,ischaemia
CMprecipitationofTammHorsefallproteinsthatblockstubules
Swellingofrenaltubularcellscausingobstruction
 Thirdmostcommoncauseofinhospitalrenalfailureafter
hypertensionandsurgery,
 Itsdefinedaselevationof creatinine2or5-1.0mg/dlwithin72hours
afteradministrationofcontrast.
 Usuallyasymptomatic

51.  Riskfactorsinclude:
 Age>65years
 Diabetestreatedwithinsulinorotherprescribedmedication
 Receivingchemotherapyor aminoglycosidewithinthepast1month
 Diagnosisof acollagenvasculardisease
 Diagnosisof aparaproteinemiasyndrome/disease(e.g. multiple
myeloma)
 Historyofakidneytransplant,renaltumor,renalsurgery,orsingle
kidney
 Historyofendstageliverdisease
 Historyofseverecongestiveheartfailure
 Nephrotoxicityprevention:
 Detailedpatienthistorybeforeprocedure
 Screeningforrenaldisease(serum creatinine)escptheoneswiththe
aboveriskfactors.

52.  CARDIOVASCULARTOXICITY
 Patientswithunderlyingcardiacdiseasehaveanincreasedincidence
and/orseverityofcardiovascularsideeffects.
 Pulmonaryangiographyandintracardiacandcoronaryartery
injectionscarrythehighestdegreeofrisk.
 Possiblereactionsincludehypotension,tachycardia,and
arrhythmias.Moresevere,butuncommon reactionsinclude
congestiveheartfailure,pulmonaryedema,andcardiacarrest

53.  NEUROTOXICITY
 Iodinatedcontrastagentscauseachangeintheblood-brainbarrier
duetotheirhypertonicity.
 Theserisksarereducedwhenlowor iso-osmolaragentsareused.
 Potentialreactionsincludeheadache,confusion,seizures,altered
consciousness,visualdisturbances,anddizziness.

54.  VASOVAGALREACTIONS
 Vasovagalreactionsarecharacterizedbybradycardiaand
hypotension.
 Initialresuscitationshouldincludeelevatingthelegsand/orplacing
thepatientinaTrendelenburgpositionandadministeringoxygenat
therateof6–10liters/minute.
 Atropinemaybeusedintheinitialtreatmentof bradycardia.
Epinephrinemaybenecessary.
 IVfluidsareusedtotreathypotensionandshouldbeadministered
rapidly.
 Itisimportanttomonitorvitalsignsfrequentlytotitratetheamountof
medicationsandfluidsthatareused.

55. CONTRASTEXTRAVASATION•
 Itreferstotheescapeofthecontrastmaterialfromthevesselin
whichitisintroduced,intothesurroundingtissueorbodycavity
 Riskfactors:
Atherosclerosis,
Diabetes,
Raynaud’sdisease,
Venousthrombosis,
priorradiation,
extensivesurgery,
severelyillanddeblitated,
indwellinglines>24hrs,
multipleinjectionsinontosamevein.

56.  Clinicalfeatures:
Mild–edema, erythema,stinging,tenderness
Severe–Compartmentsyndrome,ulcers,necrosis.
 Preventionisbetterthancure:
ensureproperlysecuredIVaccess,extravasationdetectors
 Treatment:
dependsonthevolumeofextravasation

57. EMERGENCYRESPONSE
 Immediatecessation of injectionwhenaproblemisdetected.
 Notificationofresponsible physicians.
 Initialtreatment:
 a.Elevatetheaffectedextremityabovetheleveloftheheart
 b.Intermittent,brief compression tomilkthe extravasatecentrally,canbeapplied
withanacewrap.(DONOTleavethewraponfor morethan1minutetoavoid
compartmentsyndrome.)
 cObservation
 d.Notificationofthereferring physicianifthepatientbecomessymptomatic.
 Indicationsforplasticsurgeryconsultation(anyoneofthefollowing):
a.Progressive swellingorpain
b.Decreasedcapillaryrefill
c.Alteredsensation
d.Skinulcerationorblistering.
 Instructionsaregiventothepatient.
 ollow-upcalls.
 Documentation.

58. CONCLUSIONS
 Although contrastagentsarewidely usedwithsafe outcomesandlittle orno
sideeffects, adversereactionsnonetheless mayoccur. Theymaybesevere,
andtheymayprogress rapidly. Successful patientmanagementduring
contrastenhanced examinations requiresall ofthefollowing:
1. Knowledge ofthepatient’smedical history.
2. Patientpreparation, including premedication, ifnecessary.
3. Proper selection oftheagenttobeused.
4. Knowledge ofthepathophysiology of contrastreactions.
5. Prompt recognition andaccurateassessmentof reactions.
6. Immediateavailability of necessaryequipmentand drugs.
7. Adequateprior planning andtraining.
8. Current knowledge of medicationsandothertreatmentoptions.
Insummary,vigilance andattention todetail arekey.Expecttheunexpected
andbeprepared.

59. THANKYOU

60.  References:
 ContrastMediaClassificationandTerminologyHenrikS.Thomsen,
Marie-FranceBellin,JarlÅ. Jakobsen,JudithA.W.Webb
 CONTRASTMEDIATUTORIALJessicaB. Robbins,MDMyronA. Pozniak,MD