ASMIRT - MRI ACCREDITATION
QUESTIONS WITH CORRECT ANSWERS
Mild xxsensory xxeffects xxdue xxto xxstatic xxmagnetic xxfields xxinclude: xx- xxAnswer xx•
xxVertigo xx
• xxNausea xx
• xxTaste xxSensations
Sensory xxeffects xxof xxthe xxstatic xxmagnetic xxfield xxincrease xxor xxdecrease xxwith xxfield
xxstrength? xx- xxAnswer xxSensory xxeffects xxare xxrelated xxto xxthe xxstrength xxof xxthe
xxmagnetic xxfield xxwith xxfew xxsymptoms xxat xx1.5T xxand xxmore xxappearing
xxapproaching xxa xx4T xxfield xxstrength
Explain xxwhat xxt-wave xxartefact xxis xxand xxwhy xxit xxoccurs xx- xxAnswer xxAny xxcharged
xxparticle xxmoving xxthrough xxa xxmagnetic xxfield xxwill xxhave xxa xxcurrent xxinduced xxvia
xxthis xxinteraction. xxAs xxblood, xxa xxconductive xxfluid xxflows xxthrough xxa xxmagnetic
xxfield xxit xxinduces xxan xxelectrical xxbiopotential. xxThis xxelectrical xxbiopotential xxcan
xxbe xxseen xxon xxthe xxECG xxwaveform xxof xxpatients xxin xxMRI. xxIt xxis xxdemonstrated
xxby xxan xxincrease xxin xxthe xxT-wave xxamplitude xxon xxECG. xxThis xxchange xxin xxT-
wave xxamplitude xxis xxdirectly xxproportional xxto xxthe xxstrength xxof xxthe xxStatic xxFiled.
xxIt xxis xximportant xxthat xxMR xxradiographers xxare xxaware xxof xxthis xxas xxelevated xxT-
waves xxare xxalso xxassociated xxwith xxischemia xxand xxmyocardial xxinfarction.
What xxrisks xxdoes xxthe xxstatic xxmagnetic xxfield xxpose xxin xxterms xxof xximplants xxand
xxobjects? xx- xxAnswer xxStatic xxFields xxalso xxpose xxhazards xxthrough xxthe
xxdisplacement xxof xxferro-magnetic xximplants xxand xxobjects. xxThe xxstatic xxfield
xximparts xxboth xxa xxtranslation xx(attractive xxforce) xxand xxa xxtorque xx(twisting xxforce).
xxThe xxstrong xxnature xxof xxthe xxStatic xxField xxalso xxhas xxthe xxpotential xxto xxdisrupt
xxthe xxfunction xxof xxCardiac xxPacemakers. xxAnyone xxentering xxbeyond xxthe xx5G xxline
xxshould xxbe xxscreened xxfor xxcontraindications xxto xxstrong xxMagnetic xxFields. xxAlso
xxbe xxaware xxof xxwhat xxis xxbeing xxtaken xxover xxthe xx5G xxline.
What xxstrategies xxcan xxbe xxemployed xxto xxreduce xxthe xxrisks xxof xxthe xxstatic
xxmagnetic xxfield xximpacting xxon xximplants xxand xxobjects? xx- xxAnswer xx•
xxFerromagnetic xxobjects xxmay xxbecome xxairborne xx- xx40 xxkm/hr xxterminal xxvelocity
xxpossible xxat xx1.5T xx
• xxTest xxany xxmetal xxobjects xxwith xxa xxhand xxheld xxmagnet xxbefore xxallowing xxthem
xxto xxenter xxthe xxroom. xx
• xxKeep xxthe xxgeneral xxpublic xxbehind xxthe xx5G xxline. xx•
,xxPossible xxcontra-indications xxinclude xxpacemakers, xxaneurysm xxclips, xxintra-
vascular xxcoils xxand xxstents, xxheart xxvalves, xxpenile xximplants, xxcochlear xximplants,
xxocular xximplants xx(Fatio xxeyelid xxsprings), xxneuro xxstimulators, xxbone xxgrowth
xxstimulators, xxdrug xxinfusion xxpumps.
What xxeffect xxdo xxgradient xxmagnetic xxfields xxhave xxon xxpatient xxsafety? xx- xxAnswer
xxFaraday's xxLaw xxdictates xxthat xxchanging xxmagnetic xxfields xxwill xxgenerate xxa
xxvoltage xxand xxa xxcurrent xxin xxa xxconductor. xxThe xxswitching xxof xxthe xxgradients
xxinduces xxelectrical xxcurrents xxin xxconductive xxtissues. xxVoltage xxgeneration xxwill
xxoccur xxduring xxthe xxrise xxand xxfall xxtimes xx- xxie. xxwhile xxthe xxfield xxis xxchanging.
xxThe xxlargest xxvoltages xxwill xxbe xxgenerated xxat xxthe xxperiphery xxwhere xxthe
xxgradient xxamplitudes xxare xxhighest. xxThe xxmost xxcommon xxresult xxof xxthese
xxvoltages xxis xxPeripheral xxNerve xxStimulation xx(PNS). xxOther xxside-effects xxare
xxlisted xxbelow;
• xxmagnetophosphenes xx- xxelectromagnetically xxinduced xxflashes xxof xxlight xx
• xxseizures xx
• xxtissue xxheating xx
• xxperipheral xxnerve xxstimulation xx
• xxmuscle xxcontractions xx
• xxcardiac xxarrhythmias
• xxsome xxdegree xxof xxpatient xxheating xxhas xxbeen xxshown xxto xxbe xxa xxresult xxof
xxGradient xxMagnetic xxeffects. xxHowever, xxthis xxhas xxbeen xxshown xxto xxbe xxso xxlow
xxas xxto xxbe xxnegligible
What xxstrategies xxcan xxbe xxemployed xxto xxkeep xxgradient xxeffects xxto xxa xxminimum?
xx- xxAnswer xxIn xxorder xxto xxkeep xxthese xxeffects xxto xxa xxminimum xxthe xxfollowing xxis
xxrecommended. xx
• xxkeep xxdB/dT xxless xxthan xxthose xxrequired xxto xxproduce xxperipheral xxnerve
xxstimulation. xx
• xxmax xxlimit xxfor xxdB/dT xxof xx6 xxTesla xx/ xxsec
What xxis xxthe xxcause xxof xxacoustic xxnoise xxduring xxan xxMRI xxscan? xx- xxAnswer xxThe
xxcharacteristic xxnoise xxthat xxis xxheard xxduring xxan xxMRI xxscan xxis xxthe xxresult xxof
xxthe xxinteraction xxof xxLorentz xxforces xxgenerated xxby xxthe xxGradient xxCoil xxwhen xxa
xxcurrent xxis xxpulsed xxthrough xxthem xxin xxthe xxpresence xxof xxa xxStatic xxMagnetic
xxField. xxThe xxnoise xxresults xxas xxthese xxforces xxare xxso xxstrong xxas xxto xxtwist xxthe
xxcoils xxon xxtheir xxmounts. xxIn xxsome xxcases xxthis xxcan xxbe xxin xxexcess xxof xx100dB
xxparticularly xxwhen xxrunning xxEPI xxsequences. xxThus xxall xxpatients xxneed xxto xxbe
xxprovided xxhearing xxprotection.
What xxis xxthe xxgreatest xxconcern xxin xxterms xxof xxMR xxsafety? xx- xxAnswer xxRF
xxeffects xxare xxof xxthe xxgreatest xxconcern xxin xxterms xxof xxMR xxsafety. xxThe xxmain
xxeffect xxis xxthe xxdeposition xxof xxenergy xxresulting xxin xxtissue xxheating. xxOf xxparticular
xxconcern xxare xxheat xxsensitive xxorgans xxsuch xxas xxthe xxeyes xxand xxtestes. xxOne xxof
xxthe xxmajor xxconcerns xxis xxwhere xxa xxpatient xxhas xxa xxmetallic xximplant xxwhich
xxresults xxin xxgreater xxheating.
,RF xxfield xxsafety xxconcerns xxincrease xxor xxdecrease xxwith xxincreasing xxfield
xxstrength> xx- xxAnswer xxThe xxamount xxof xxenergy xxabsorbed xxwill xxincrease xxwith
xxfrequency xxof xxthe xxRF xxfield xxdelivered xxand xxis xxtherefore xxgreater xxat xxhigher
xxfield xxstrengths
What xxis xxSAR? xx- xxAnswer xxSAR= xxSpecific xxAbsorption xxRate xx- xxthe xxterm xxused
xxto xxdescribe xxenergy xxdissipation
SAR xxis xxexpressed xxin: xx- xxAnswer xxWatts xx/ xxkg
SAR xxwill xxdepend xxon xxfactors xxincluding: xx- xxAnswer xx• xxfrequency xx(& xxtherefore
xxthe xxfield xxstrength) xx
• xxRF xxpulse xx- xxwhere xxpower xxdeposited xxis xxproportional xxto xx(flip xxangle xx/ xx90) xx
• xxTR
• xxRF xxcoil xx- xxtransmit xx/ xxreceive xxor xxreceive xxonly xx
• xxvolume xxof xxtissue xxwithin xxthe xxcoil xx
• xxconductivity xxof xxthe xxtissue
What xxdetermines xxthe xxSAR xxcalculation? xx- xxAnswer xxThe xxSAR xxis xxcalculated
xxfor xxeach xxsequence xxon xxthe xxbasis xxof xxthe xxsequence xxparameters xxand xxthe
xxpatient xxweight
What xxare xxthe xxFDA xxrecommendations xxregarding xxSAR? xx- xxAnswer xx• xxMaximum
xxSAR xxof xx0.4 xxW/kg xx(whole xxbody)
• xx3.2 xxW/kg xx(head) xx
• xx8.0 xxW/kg xx(in xxany xxone xxgram xxof xxtissue) xx
• xxRF xxexposure xxshould xxbe xxinsufficient xxto xxproduce xxa xxcore xxtemperature
xxincrease xxof xx1 xxdegree xxC
Why xxis xxpatient xxheating xxa xxconcern xxin xxMRI? xx- xxAnswer xx• xxHeating xxwill xxalso
xxvary xxwith xxthe xxstate xxof xxthe xxpatient's xxthermo-regulatory xxsystem, xxthe xxambient
xxtemperature, xxthe xxhumidity xxand xxthe xxair xxflow xxaround xxthe xxpatient. xx
• xxThe xxeye xxand xxthe xxtestes xxare xxparticularly xxsensitive xxorgans xxdue xxto xxa xxlow
xxcapacity xxfor xxheat xxdissipation. xx
• xxExcessive xxRF xxexposure xxand xxtemperature xxincrease xxcan xxlead xxto xxan
xxincrease xxin xxblood xxpressure xxand xxheart xxrate.
A xxSAR xxwarning xxappears xxduring xxa xxscan xxpreventing xxyou xxfrom xxcontinuing
xxwith xxan xxexamination xxunless xxfactors xxare xxaltered xxto xxa xxsafe xxlevel, xxwhat xxcan
xxbe xxchanged xxin xxorder xxto xxachieve xxthis? xx- xxAnswer xxFactors xxwhich xxwill
xxreduce xxSAR xxif xxrequired xxinclude: xx
• xxreducing xxthe xxnumber xxof xxslices xx
• xxreducing xxthe xxETL xx
• xxincreasing xxthe xxTR xx
• xxGE xxrather xxthan xxSE xx
, • xxUse xxquadrature xxcoils xxrather xxthan xxlinear xxcoils xxfor xxtransmission xx
• xxChange xxto xxlow xxSAR xxsequence xxdesign
How xxcan xxpatient xxburns xxbe xxavoided? xx- xxAnswer xx• xxuse xxonly xxequipment
xxtested xxto xxbe xxMR xxcompatible xx
• xxallow xxonly xxMR xxtrained xxstaff xxto xxuse xxthe xxequipment xx
• xxcheck xxthe xxintegrity xxof xxthe xxelectrical xxinsulation xxof xxall xxcables xx
• xxremove xxall xxunnecessary xxelectrically xxconductive xxequipment xxfrom xxthe xxbore xx
• xxkeep xxelectrically xxconductive xxequipment xxfrom xxdirectly xxcontacting xxthe xxpatient
xx
• xxkeep xxelectrically xxconductive xxequipment xxfrom xxforming xxlarge xxdiameter
xxconductive xxloops xx
• xxposition xxcables xxto xxavoid xxcross xxpoints xx
• xxposition xxECG xxcables xxto xxexit xxdown xxthe xxcentre xxof xxthe xxbore xx
• xxdo xxnot xxallow xxcontact xxbetween xxthe xxpatient's xxskin xxand xxthe xxmagnet xxbore
Explain xxthe xxdeleterious xxeffects xxof xxMRI xxon xxpregnant xxpatients xx- xxAnswer
xxThere xxare xxno xxknown xxbiological xxeffects xxof xxMRI xxon xxfoetuses. xxMR xximaging
xxmay xxbe xxused xxin xxpregnant xxwomen xxif xxother xxnon-ionizing xxforms xxof
xxdiagnostic xximaging xxare xxinadequate xxor xxif xxthe xxexamination xxprovides xximportant
xxinformation xxthat xxwould xxotherwise xxrequire xxexposure xxto xxionizing xxradiation
xx(e.g., xxfluoroscopy, xxCT, xxetc.). xxPregnant xxpatients xxshould xxbe xxinformed xxthat,
xxto xxdate, xxthere xxhas xxbeen xxno xxindication xxthat xxthe xxuse xxof xxclinical xxMR
xximaging xxduring xxpregnancy xxhas xxproduced xxdeleterious xxeffects." xxThis xxpolicy
xxhas xxbeen xxadopted xxby xxthe xxAmerican xxCollege xxof xxRadiology xxand xxis
xxconsidered xxto xxbe xxthe xx"standard xxof xxcare" xxwith xxrespect xxto xxthe xxuse xxof xxMRI
xxprocedures xxin xxpregnant xxpatients. xxImportantly, xxthis xxinformation xxapplies xxto
xxMR xxsystems xxoperating xxup xxto xxand xxincluding xx3-Tesla. xx(MR xxImaging xxSafety
xxand xxPatient xxManagement xxissued xxby xxthe xxSafety xxCommittee xxof xxthe xxSociety
xxfor xxMagnetic xxResonance xxImaging) xxPregnant xxpatients xxshould xxbe xxreviewed
xxon xxa xxcase xxby xxcase xxbasis xxto xxassess xxwhether xxthe xxrisks xxoutweigh xxthe
xxpotential xxbenefits.
Can xxpregnant xxstaff xxenter xxthe xxMRI xxenvironment? xx- xxAnswer xxNo xxincreased
xxincidence xxof xxspontaneous xxabortion xxhas xxbeen xxdemonstrated xxamong xxMR
xxradiographers xxor xxnurses. xxThe xxmost xxcommon xxpolicy xxseems xxto xxbe xxthat
xxpregnant xxstaff xxare xxallowed xxexposure xxto xxthe xxstatic xxfield xx(ie. xxto xxset
xxpatients xxup) xxbut xxleave xxthe xxroom xxduring xximage xxacquisition xxto xxavoid
xxexposure xxto xxRF xxand xxgradient xxfields.
Is xxcontrast xxrecommended xxin xxpregnant xxpatients? xx- xxAnswer xxContrast xxis xxnot
xxrecommended xxduring xxpregnancy. xxIt xxhas xxbeen xxshown xxto xxcross xxthe
xxplacenta.
What xxis xxa xxquench? xx- xxAnswer xxQuenching xxthe xxmagnet xxresults xxin xxa xxlarge
xxamount xxof xxhelium xxgas xxboil xxoff xxfrom xxliquid xxhelium xxinside xxthe xxmagnet.
xxOne xxlitre xxof xxliquid xxhelium xxexpands xxto xx760 xxlitres xxof xxhelium xxgas. xxDuring xxa
QUESTIONS WITH CORRECT ANSWERS
Mild xxsensory xxeffects xxdue xxto xxstatic xxmagnetic xxfields xxinclude: xx- xxAnswer xx•
xxVertigo xx
• xxNausea xx
• xxTaste xxSensations
Sensory xxeffects xxof xxthe xxstatic xxmagnetic xxfield xxincrease xxor xxdecrease xxwith xxfield
xxstrength? xx- xxAnswer xxSensory xxeffects xxare xxrelated xxto xxthe xxstrength xxof xxthe
xxmagnetic xxfield xxwith xxfew xxsymptoms xxat xx1.5T xxand xxmore xxappearing
xxapproaching xxa xx4T xxfield xxstrength
Explain xxwhat xxt-wave xxartefact xxis xxand xxwhy xxit xxoccurs xx- xxAnswer xxAny xxcharged
xxparticle xxmoving xxthrough xxa xxmagnetic xxfield xxwill xxhave xxa xxcurrent xxinduced xxvia
xxthis xxinteraction. xxAs xxblood, xxa xxconductive xxfluid xxflows xxthrough xxa xxmagnetic
xxfield xxit xxinduces xxan xxelectrical xxbiopotential. xxThis xxelectrical xxbiopotential xxcan
xxbe xxseen xxon xxthe xxECG xxwaveform xxof xxpatients xxin xxMRI. xxIt xxis xxdemonstrated
xxby xxan xxincrease xxin xxthe xxT-wave xxamplitude xxon xxECG. xxThis xxchange xxin xxT-
wave xxamplitude xxis xxdirectly xxproportional xxto xxthe xxstrength xxof xxthe xxStatic xxFiled.
xxIt xxis xximportant xxthat xxMR xxradiographers xxare xxaware xxof xxthis xxas xxelevated xxT-
waves xxare xxalso xxassociated xxwith xxischemia xxand xxmyocardial xxinfarction.
What xxrisks xxdoes xxthe xxstatic xxmagnetic xxfield xxpose xxin xxterms xxof xximplants xxand
xxobjects? xx- xxAnswer xxStatic xxFields xxalso xxpose xxhazards xxthrough xxthe
xxdisplacement xxof xxferro-magnetic xximplants xxand xxobjects. xxThe xxstatic xxfield
xximparts xxboth xxa xxtranslation xx(attractive xxforce) xxand xxa xxtorque xx(twisting xxforce).
xxThe xxstrong xxnature xxof xxthe xxStatic xxField xxalso xxhas xxthe xxpotential xxto xxdisrupt
xxthe xxfunction xxof xxCardiac xxPacemakers. xxAnyone xxentering xxbeyond xxthe xx5G xxline
xxshould xxbe xxscreened xxfor xxcontraindications xxto xxstrong xxMagnetic xxFields. xxAlso
xxbe xxaware xxof xxwhat xxis xxbeing xxtaken xxover xxthe xx5G xxline.
What xxstrategies xxcan xxbe xxemployed xxto xxreduce xxthe xxrisks xxof xxthe xxstatic
xxmagnetic xxfield xximpacting xxon xximplants xxand xxobjects? xx- xxAnswer xx•
xxFerromagnetic xxobjects xxmay xxbecome xxairborne xx- xx40 xxkm/hr xxterminal xxvelocity
xxpossible xxat xx1.5T xx
• xxTest xxany xxmetal xxobjects xxwith xxa xxhand xxheld xxmagnet xxbefore xxallowing xxthem
xxto xxenter xxthe xxroom. xx
• xxKeep xxthe xxgeneral xxpublic xxbehind xxthe xx5G xxline. xx•
,xxPossible xxcontra-indications xxinclude xxpacemakers, xxaneurysm xxclips, xxintra-
vascular xxcoils xxand xxstents, xxheart xxvalves, xxpenile xximplants, xxcochlear xximplants,
xxocular xximplants xx(Fatio xxeyelid xxsprings), xxneuro xxstimulators, xxbone xxgrowth
xxstimulators, xxdrug xxinfusion xxpumps.
What xxeffect xxdo xxgradient xxmagnetic xxfields xxhave xxon xxpatient xxsafety? xx- xxAnswer
xxFaraday's xxLaw xxdictates xxthat xxchanging xxmagnetic xxfields xxwill xxgenerate xxa
xxvoltage xxand xxa xxcurrent xxin xxa xxconductor. xxThe xxswitching xxof xxthe xxgradients
xxinduces xxelectrical xxcurrents xxin xxconductive xxtissues. xxVoltage xxgeneration xxwill
xxoccur xxduring xxthe xxrise xxand xxfall xxtimes xx- xxie. xxwhile xxthe xxfield xxis xxchanging.
xxThe xxlargest xxvoltages xxwill xxbe xxgenerated xxat xxthe xxperiphery xxwhere xxthe
xxgradient xxamplitudes xxare xxhighest. xxThe xxmost xxcommon xxresult xxof xxthese
xxvoltages xxis xxPeripheral xxNerve xxStimulation xx(PNS). xxOther xxside-effects xxare
xxlisted xxbelow;
• xxmagnetophosphenes xx- xxelectromagnetically xxinduced xxflashes xxof xxlight xx
• xxseizures xx
• xxtissue xxheating xx
• xxperipheral xxnerve xxstimulation xx
• xxmuscle xxcontractions xx
• xxcardiac xxarrhythmias
• xxsome xxdegree xxof xxpatient xxheating xxhas xxbeen xxshown xxto xxbe xxa xxresult xxof
xxGradient xxMagnetic xxeffects. xxHowever, xxthis xxhas xxbeen xxshown xxto xxbe xxso xxlow
xxas xxto xxbe xxnegligible
What xxstrategies xxcan xxbe xxemployed xxto xxkeep xxgradient xxeffects xxto xxa xxminimum?
xx- xxAnswer xxIn xxorder xxto xxkeep xxthese xxeffects xxto xxa xxminimum xxthe xxfollowing xxis
xxrecommended. xx
• xxkeep xxdB/dT xxless xxthan xxthose xxrequired xxto xxproduce xxperipheral xxnerve
xxstimulation. xx
• xxmax xxlimit xxfor xxdB/dT xxof xx6 xxTesla xx/ xxsec
What xxis xxthe xxcause xxof xxacoustic xxnoise xxduring xxan xxMRI xxscan? xx- xxAnswer xxThe
xxcharacteristic xxnoise xxthat xxis xxheard xxduring xxan xxMRI xxscan xxis xxthe xxresult xxof
xxthe xxinteraction xxof xxLorentz xxforces xxgenerated xxby xxthe xxGradient xxCoil xxwhen xxa
xxcurrent xxis xxpulsed xxthrough xxthem xxin xxthe xxpresence xxof xxa xxStatic xxMagnetic
xxField. xxThe xxnoise xxresults xxas xxthese xxforces xxare xxso xxstrong xxas xxto xxtwist xxthe
xxcoils xxon xxtheir xxmounts. xxIn xxsome xxcases xxthis xxcan xxbe xxin xxexcess xxof xx100dB
xxparticularly xxwhen xxrunning xxEPI xxsequences. xxThus xxall xxpatients xxneed xxto xxbe
xxprovided xxhearing xxprotection.
What xxis xxthe xxgreatest xxconcern xxin xxterms xxof xxMR xxsafety? xx- xxAnswer xxRF
xxeffects xxare xxof xxthe xxgreatest xxconcern xxin xxterms xxof xxMR xxsafety. xxThe xxmain
xxeffect xxis xxthe xxdeposition xxof xxenergy xxresulting xxin xxtissue xxheating. xxOf xxparticular
xxconcern xxare xxheat xxsensitive xxorgans xxsuch xxas xxthe xxeyes xxand xxtestes. xxOne xxof
xxthe xxmajor xxconcerns xxis xxwhere xxa xxpatient xxhas xxa xxmetallic xximplant xxwhich
xxresults xxin xxgreater xxheating.
,RF xxfield xxsafety xxconcerns xxincrease xxor xxdecrease xxwith xxincreasing xxfield
xxstrength> xx- xxAnswer xxThe xxamount xxof xxenergy xxabsorbed xxwill xxincrease xxwith
xxfrequency xxof xxthe xxRF xxfield xxdelivered xxand xxis xxtherefore xxgreater xxat xxhigher
xxfield xxstrengths
What xxis xxSAR? xx- xxAnswer xxSAR= xxSpecific xxAbsorption xxRate xx- xxthe xxterm xxused
xxto xxdescribe xxenergy xxdissipation
SAR xxis xxexpressed xxin: xx- xxAnswer xxWatts xx/ xxkg
SAR xxwill xxdepend xxon xxfactors xxincluding: xx- xxAnswer xx• xxfrequency xx(& xxtherefore
xxthe xxfield xxstrength) xx
• xxRF xxpulse xx- xxwhere xxpower xxdeposited xxis xxproportional xxto xx(flip xxangle xx/ xx90) xx
• xxTR
• xxRF xxcoil xx- xxtransmit xx/ xxreceive xxor xxreceive xxonly xx
• xxvolume xxof xxtissue xxwithin xxthe xxcoil xx
• xxconductivity xxof xxthe xxtissue
What xxdetermines xxthe xxSAR xxcalculation? xx- xxAnswer xxThe xxSAR xxis xxcalculated
xxfor xxeach xxsequence xxon xxthe xxbasis xxof xxthe xxsequence xxparameters xxand xxthe
xxpatient xxweight
What xxare xxthe xxFDA xxrecommendations xxregarding xxSAR? xx- xxAnswer xx• xxMaximum
xxSAR xxof xx0.4 xxW/kg xx(whole xxbody)
• xx3.2 xxW/kg xx(head) xx
• xx8.0 xxW/kg xx(in xxany xxone xxgram xxof xxtissue) xx
• xxRF xxexposure xxshould xxbe xxinsufficient xxto xxproduce xxa xxcore xxtemperature
xxincrease xxof xx1 xxdegree xxC
Why xxis xxpatient xxheating xxa xxconcern xxin xxMRI? xx- xxAnswer xx• xxHeating xxwill xxalso
xxvary xxwith xxthe xxstate xxof xxthe xxpatient's xxthermo-regulatory xxsystem, xxthe xxambient
xxtemperature, xxthe xxhumidity xxand xxthe xxair xxflow xxaround xxthe xxpatient. xx
• xxThe xxeye xxand xxthe xxtestes xxare xxparticularly xxsensitive xxorgans xxdue xxto xxa xxlow
xxcapacity xxfor xxheat xxdissipation. xx
• xxExcessive xxRF xxexposure xxand xxtemperature xxincrease xxcan xxlead xxto xxan
xxincrease xxin xxblood xxpressure xxand xxheart xxrate.
A xxSAR xxwarning xxappears xxduring xxa xxscan xxpreventing xxyou xxfrom xxcontinuing
xxwith xxan xxexamination xxunless xxfactors xxare xxaltered xxto xxa xxsafe xxlevel, xxwhat xxcan
xxbe xxchanged xxin xxorder xxto xxachieve xxthis? xx- xxAnswer xxFactors xxwhich xxwill
xxreduce xxSAR xxif xxrequired xxinclude: xx
• xxreducing xxthe xxnumber xxof xxslices xx
• xxreducing xxthe xxETL xx
• xxincreasing xxthe xxTR xx
• xxGE xxrather xxthan xxSE xx
, • xxUse xxquadrature xxcoils xxrather xxthan xxlinear xxcoils xxfor xxtransmission xx
• xxChange xxto xxlow xxSAR xxsequence xxdesign
How xxcan xxpatient xxburns xxbe xxavoided? xx- xxAnswer xx• xxuse xxonly xxequipment
xxtested xxto xxbe xxMR xxcompatible xx
• xxallow xxonly xxMR xxtrained xxstaff xxto xxuse xxthe xxequipment xx
• xxcheck xxthe xxintegrity xxof xxthe xxelectrical xxinsulation xxof xxall xxcables xx
• xxremove xxall xxunnecessary xxelectrically xxconductive xxequipment xxfrom xxthe xxbore xx
• xxkeep xxelectrically xxconductive xxequipment xxfrom xxdirectly xxcontacting xxthe xxpatient
xx
• xxkeep xxelectrically xxconductive xxequipment xxfrom xxforming xxlarge xxdiameter
xxconductive xxloops xx
• xxposition xxcables xxto xxavoid xxcross xxpoints xx
• xxposition xxECG xxcables xxto xxexit xxdown xxthe xxcentre xxof xxthe xxbore xx
• xxdo xxnot xxallow xxcontact xxbetween xxthe xxpatient's xxskin xxand xxthe xxmagnet xxbore
Explain xxthe xxdeleterious xxeffects xxof xxMRI xxon xxpregnant xxpatients xx- xxAnswer
xxThere xxare xxno xxknown xxbiological xxeffects xxof xxMRI xxon xxfoetuses. xxMR xximaging
xxmay xxbe xxused xxin xxpregnant xxwomen xxif xxother xxnon-ionizing xxforms xxof
xxdiagnostic xximaging xxare xxinadequate xxor xxif xxthe xxexamination xxprovides xximportant
xxinformation xxthat xxwould xxotherwise xxrequire xxexposure xxto xxionizing xxradiation
xx(e.g., xxfluoroscopy, xxCT, xxetc.). xxPregnant xxpatients xxshould xxbe xxinformed xxthat,
xxto xxdate, xxthere xxhas xxbeen xxno xxindication xxthat xxthe xxuse xxof xxclinical xxMR
xximaging xxduring xxpregnancy xxhas xxproduced xxdeleterious xxeffects." xxThis xxpolicy
xxhas xxbeen xxadopted xxby xxthe xxAmerican xxCollege xxof xxRadiology xxand xxis
xxconsidered xxto xxbe xxthe xx"standard xxof xxcare" xxwith xxrespect xxto xxthe xxuse xxof xxMRI
xxprocedures xxin xxpregnant xxpatients. xxImportantly, xxthis xxinformation xxapplies xxto
xxMR xxsystems xxoperating xxup xxto xxand xxincluding xx3-Tesla. xx(MR xxImaging xxSafety
xxand xxPatient xxManagement xxissued xxby xxthe xxSafety xxCommittee xxof xxthe xxSociety
xxfor xxMagnetic xxResonance xxImaging) xxPregnant xxpatients xxshould xxbe xxreviewed
xxon xxa xxcase xxby xxcase xxbasis xxto xxassess xxwhether xxthe xxrisks xxoutweigh xxthe
xxpotential xxbenefits.
Can xxpregnant xxstaff xxenter xxthe xxMRI xxenvironment? xx- xxAnswer xxNo xxincreased
xxincidence xxof xxspontaneous xxabortion xxhas xxbeen xxdemonstrated xxamong xxMR
xxradiographers xxor xxnurses. xxThe xxmost xxcommon xxpolicy xxseems xxto xxbe xxthat
xxpregnant xxstaff xxare xxallowed xxexposure xxto xxthe xxstatic xxfield xx(ie. xxto xxset
xxpatients xxup) xxbut xxleave xxthe xxroom xxduring xximage xxacquisition xxto xxavoid
xxexposure xxto xxRF xxand xxgradient xxfields.
Is xxcontrast xxrecommended xxin xxpregnant xxpatients? xx- xxAnswer xxContrast xxis xxnot
xxrecommended xxduring xxpregnancy. xxIt xxhas xxbeen xxshown xxto xxcross xxthe
xxplacenta.
What xxis xxa xxquench? xx- xxAnswer xxQuenching xxthe xxmagnet xxresults xxin xxa xxlarge
xxamount xxof xxhelium xxgas xxboil xxoff xxfrom xxliquid xxhelium xxinside xxthe xxmagnet.
xxOne xxlitre xxof xxliquid xxhelium xxexpands xxto xx760 xxlitres xxof xxhelium xxgas. xxDuring xxa
