科研进展基于ADC的不均匀指数对胰腺

DifferentiatingPancreaticCancerfromMass-FormingFocalPancreatitiswithaNovelInhomogeneityIndexBasedonADCMapAnalysis

ChaoMa1,LiLiu1,JingLi1,LiWang1,XuFang1,JianxunQu2,Shi-yueChen1,andJianpingLu1

1DepartmentofRadiology,ChanghaiHospitalofShanghai,Shanghai,China,PeoplesRepublicof,2MRResearchChina,GEHealthcare,Beijing,China,PeoplesRepublicof

Differentiatingmass-formingfocalpancreatitis(FP)andpancreaticductaladenocarcinoma(PDAC)isofgreatimportanceandyetremainsachallengeinclinicalpractice.Inthiswork,weproposeanovelmethodtoaddressthechallengewithanewparameter(inhomogeneityindex)basedontheADCmapanalysiswithdifferentregionofinterest(ROI)size.

Diffusionweightedimaging(DWI),withquantitativemeasurementofapparentdiffusioncoefficient(ADC)values,isroutinelyperformedinclinicalpracticeindetectionandcharacterizationofpancreaticdiseases[1].Differentiatingmass-formingfocalpancreatitis(FP)andpancreaticductaladenocarcinoma(PDAC)isofgreatclinicalimportanceasdistinctivetreatmentsareusuallycarriedout.Fornow,thereisstilldiagnosticchallengeindifferentiatingFPandPDAC[2,3].Inthiswork,weproposeanovelmethodtoaddresstheneedabovewithanewparameter(inhomogeneityindex)basedontheADCmapanalysiswithdifferentregionofinterest(ROI)size.

Sixty-fourpatientswithpathology-provenPDAC,sixpatientswithpathology-provenFPandeighteenhealthyvolunteerswererecruitedandunderwentDWI(b-values=0,s/mm2)on3.0Twholebodysystem(GEHDxt).ADCmapswerecalculatedonavoxel-by-voxelbasisfromtheobtainedDWIimagesusingmono-exponentialmodel(ADC=[ln(SIb0/SIb)]/),andwerereconstructedwithFOVof*mm2andmatrixof*.AhomemadesoftwarewasusedtomeasuremeanvalueandstandarddeviationofADC(MeanADCandSDADC)withineachof12concentricroundROIs(areas:20,42,59,82,99,,,,,,,andmm2withpixelnumbers:9,19,27,37,45,55,63,73,80,89,and,respectively)drawnonthesolidpartofthemassoflesionsandtheheadofnormalpancreasonthesinglesliceoftheADCmap,whichcontainedthelargestavailabletargetedtumorareaornormalpancreas,asillustratedinFig.1.Theinhomogeneityindex,definedastheratioofSDADCoverMeanADCineachROI,wasalsocalculatedforthelesionsandnormalpancreasforeachoftheROIwithdifferentsizes.Waterphantomwasusedtocalculatetheidealinhomogeneityindexasareferencemeasurement.

TheaveragedinhomogeneityindexcurvesofPDAC(64cases),FP(8cases),normalpancreas(18cases)andwaterphantom(8cases)areshowninFig.2.Significantdifferenceswereobservedfortheinhomogeneityindexmeasuredby12different-sizeROIsamongFP,PDACandnormalpancreas.NearlinearincrementoftheinhomogeneityindexwasobservedonhealthyvolunteerswithexpandingROI,whilenon-linearincreasingcharacterwasobservedforpatientswithFPandPDAC.Aturningpointof55mm2wasalsoseen:withregionsizebelow55mm2,inhomogeneityindexofPDACincreasesslowerthanFP;whilewithsizeabove55mm2,inhomogeneityindexofPDACincreasesfaster.InhomogeneityindexofPDACisuniformlybiggerthanthatofFPinareasdetected.

Itiswellknownthatlesionsofpancreasusuallyfeaturewithinhomogeneity.ADCmeasurementshavebeenutilizedtoinvestigatepancreaticdiseases;however,fewstudieshavedetectedtheinhomogeneitypropertiesderivedfromdifferentROIsizesinPDACorFP.Thisisthefirststudyrevealingthevariationtendencyofinhomogeneityandtheinhomogeneityindexcurvecouldbeused,butnotlimited,indifferentiatingPDAC,FPandnormalpancreas.Thisapproachmightbevaluablefordifferentiationinotherdiseaseandcouldpotentiallybeappliedin







































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