3/2/18

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CIEDrelatedartifact

AnishBhuva

BHFClinicalResearchTrainingFellowCardiologyRegistrar

NHSInnovationsFellow

Outline

• Determinantsofartifact• Distributionofartifact

Strategiestoreduceartifactfor:• Cine• LGE• Mapping

RiskvsBenefitTotal 67

Indication N(%)Amyloid 1(2%)PreVTablationscarimaging 15(22%)Cardiomyopathy 26(39%)Cardiomyopathyfollowup 8(12%)EFassessment 1(2%)Ischemiaandviability 8(12%)Myocarditis 6(9%)Thrombus 2(3%)

RiskvsBenefit

RISKNoclinicalcomplications13%minorleadparameterchange

BENEFIT49% Changeinmanagement6% Unexpectednewdiagnoses

ConventionalLGE

BENEFIT88% Changeinmanagement14%Unexpectednewdiagnoses

WB-MOCOLGE

Devicerelatedartifact:devicetype

ILR PPM ICD CRT-D

ILRs

RevealLinq

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LargerILRs

MedtronicRevealDX

Devicerelatedartifact:deviceproximity Devicerelatedartifact:deviceproximity

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SSFP SSFP GREGRE

Devicerelatedartifact:sequenceselection

• SSFPsequences(cine,perfusion,T1scout)• Balancedgradientsrequirefieldhomogeneity

• Lateenhancement• Inversionpulserequiresfieldhomogeneitytonullmyocardialsignalintensity

• Darkzoneadjacenttogenerator• Moreremotehyperintesnity fromincompleteinversion

• Reduceinhomogeneity• Pushgeneratorup• Rightsided

• Usesequenceslessaffectedbyinhomogeneity• Spinechoinsteadofgradientecho(localisers)

• NonbalancedGREcine• ReducedTE(increasebandwidth)

• AdjustinversionpulseforLGE

GRESSFP GRESSFP

Butsometimes..

Slicethickness4mmSlicethickness8mm

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FreebreathingInspiration

Perfusion

T1mappingindevicepatients

Shao J et al Magn Reson Med 2016;2:1–10 SSFP MOLLI look- locker

T1error≈60ms

Kellman P et al J Cardiovasc Magn Reson 2013;15(1):63.SCMR 2017, Moderated poster finalist

*

*

*

*

*

?Amyloidosiswithrevealdevice

T2mapping STIR

T2mappingindevicepatients

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T2starmappingindevicepatients

*

**

-70

-50

-6

36

87

185

Hemochromatosiswithpermanentpacemaker

Scarimagingiskey• LGEimagingpronetodeviceartifacts

ConventionalLGE:

MOCOSSFP WBMOCOFLASHPSIRBHFLASH

LeadartifactcanmakesubtleLGEdifficulttotell

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Overall%ofpatientswithartifact

ILR

FLASH

PPM ICD CRTD CompleteCohort

SCMR 2017

DeviceartifactsinLGEimaging

• Hyperintensity artifact• Fromoff-resonance• Signalisnotinvertedduetonarrow

bandwidthofinversionpulse

• Signalvoidartifact• Dephasing acrossvoxeldueto

susceptibilitygradient• Predominatelyinslicedirection

Signalvoid

Hyperintensity

ConventionalFLASHLGE

Combattingartifacts

phase=2*∏*∆f*TE

Minimizeoff-resonancevariationbyusingthinslices

Minimizeechotime(TE)byusingwidebandwidth

B1 (mT)

Off

reso

nanc

e (H

z)

0 0.005 0.01 0.015 0.02 0.025

-2500

-2000

-1500

-1000

-500

0

500

1000

1500

2000

2500

B1 (mT)

Off

reso

nanc

e (H

z)

0 0.005 0.01 0.015 0.02 0.025

-2500

-2000

-1500

-1000

-500

0

500

1000

1500

2000

2500

• Widebandinversion

• Thinnerslices

Acquisitionsequence• Wideband,4mmslices,singleshotFLASH,flipangle11°• Cost:LossofSNR

• TogainSNR:respiratoryMOCOaveraging• 24averages

• Benefitsinclude:• Freebreathing• PSIR

Acknowledgement: Peter Kellman

56 year old, LAD infarct, LV 30%

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Notjustimplantablecardiacdevices..Conclusions

• CardiovascularMRimagingisdiagnosticinnon-defibrillatorpatients

• Artifactisrelatedtodevice,locationandsequence

• Artifactreductionmayrequire‘onthefly’sequenceadjustment