FactorsAffectingColorFlowImages:TheCreationoftheColorFlowImage
ThemajorityoftheCFIsystemsinoperationtodayuseDopplertechniquestodeterminecolorvelocityestimates.ColorflowimagingissignificantlydifferentfromPWDopplerinthewayitgathersandprocessesinformation.
PWDopplerdisplaysthecompletespectrumofbloodflowvelocitiespresentatonesamplesite(thesamplevolume)ononescanline.Conversely...[阅读全文]
FactorsAffectingColorFlowImages:ColorLineDensity
Onsomeultrasound,systemsyoucanalsoaffectthespacingbetweenadjacentcolorscanlines.Colorlinedensityreferstothespacingonthelines.Decreasingthelinedensityincreasesthespacingbetweenadjacentscanlines,therebydecreasingthenumberoflinesinthecolorsector.
Withfewerscanlines,color-processingtimesareshorter,soframeratesincrease.However,b...[阅读全文]
FactorsAffectingColorFlowImages:ColorSectorWidth
Decreasingthecolorsectorwidthdecreasesthenumberofadjacentscanlinesusedforcolorinformation.Interrogatingfewercolorscanlinesrequireslesscolorprocessingtime,sotheframerateincreases.Theaccuracyofthecolorflowinformationremainsthesame,however,becausethecolorsectorwidthhasnoimpactonthepacketsize.Widercolorsectorsyieldlowerframerates,whilenarrowercolors...[
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FactorsAffectingColorFlowImages:PacketSize
Tocreateablackandwhiteimage,ultrasoundsystemsinterrogateeachscanlineoncefortissueinformation.However,toachieveareliablepictureofcomplexbloodflowmovementovertime,colorflowimagingsystemsmustinterrogateeachcolorscanlineseveraltimesforflowinformation.
Packetsizeisthetermforthenumberoftimestheultrasoundsystemconsecutivelyinterrogateseachcolorscanlinefo...[
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FactorsAffectingColorFlowImages:AngleDependency-2
Thefollowingdiagramsillustratethechangesinthecolordisplayastheflowanglebecomesincreasinglyclosertoparallelwiththetransmittedbeam.
Atposition1,whereflowisperpendiculartothebeamofsound,therearenodetectablefrequencyshifts.Blackindicatesaflowvelocityofzero.Atposition2,wheretheangleofincidencebetweenthebeamofsoundandtheflowisslightlymoreparallel...[
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FactorsAffectingColorFlowImages
Learningthebasics,suchasdeterminingbloodflowdirection,velocity,aliasing,andlaminarvs.turbulentbloodflow,isjustthefirststepinunderstandingCFI.Next,youmustunderstandotherfactorsthatchangethecolor,sensitivity,andaccuracyoftheimageyousee.Thesefactorsinclude:Angledependency,whichaffectstheaccuracyofthecolorvelocityestimates.Packetsize,whichaffectsnotonlytheaccuracyof...[
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ColorFlowImagingBasics:DifferentiatingBloodFlowPatterns
Themulticoloredpatternsquicklymovingacrossthescreencanbequiteconfusingtothelearner.Concentratingonjustonechamberatatime,andinonepartofthecardiaccyclemakesiteasiertoseparatecolorchanges.Forexample,ifyouaretryingtoidentifymitralregurgitationinanapicalfour-chamberview,focusontheleftatriuminsystole,andlookforbloodflowmovingawayfromthetransduc...[
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ColorFlowImagingBasics:ColorandM-modeImaging
YoumayalsofindcolorflowimaginghelpfulduringM-modestudies.CFIsuperimposedontheM-modedisplaygivesspecificdetailaboutthetiminganddurationofjets.Inthefollowingexamplethepatienthasbothmitralandaorticinsufficiancy.Aorticinsufficiency(AI),indicatedbythemosaicofcolorsintheleftventricularoutflowtractindiastole,andMitralinsufficiency(MI),indicatedbythemosaico...[
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ColorFlowImagingBasics:ColorandM-modeImaging
YoumayalsofindcolorflowimaginghelpfulduringM-modestudies.CFIsuperimposedontheM-modedisplaygivesspecificdetailaboutthetiminganddurationofjets.Inthefollowingexamplethepatienthasbothmitralandaorticinsufficiancy.Aorticinsufficiency(AI),indicatedbythemosaicofcolorsintheleftventricularoutflowtractindiastole,andMitralinsufficiency(MI),indicatedbythemosaico...[
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ColorFlowImagingBasics:ScanningTechnique
ColorFlowimaging(CFI)quicklyprovidesatremendousamountofvaluablebloodflowinformation.Examiningeachbloodflowpatterninseveraldifferentimagingviewsallowsamoreaccurateassessmentofbloodflow.
ColorFlowImagingisatwo-dimensionaltechniqueforevaluatingthree-dimensionalbloodflowovertime.Ultrasoundprovidesonlyaverythin“slice”oftheheartatanyon...[阅读全文]