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16
(2005-04-20 15:38:57)

FactorsAffectingColorFlowImages:TheCreationoftheColorFlowImage
ThemajorityoftheCFIsystemsinoperationtodayuseDopplertechniquestodeterminecolorvelocityestimates.ColorflowimagingissignificantlydifferentfromPWDopplerinthewayitgathersandprocessesinformation.

PWDopplerdisplaysthecompletespectrumofbloodflowvelocitiespresentatonesamplesite(thesamplevolume)ononescanline.Conversely...[阅读全文]
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15
(2005-04-20 15:37:55)

FactorsAffectingColorFlowImages:ColorLineDensity
Onsomeultrasound,systemsyoucanalsoaffectthespacingbetweenadjacentcolorscanlines.Colorlinedensityreferstothespacingonthelines.Decreasingthelinedensityincreasesthespacingbetweenadjacentscanlines,therebydecreasingthenumberoflinesinthecolorsector.

Withfewerscanlines,color-processingtimesareshorter,soframeratesincrease.However,b...[阅读全文]
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14
(2005-04-20 15:36:59)

FactorsAffectingColorFlowImages:ColorSectorWidth
Decreasingthecolorsectorwidthdecreasesthenumberofadjacentscanlinesusedforcolorinformation.Interrogatingfewercolorscanlinesrequireslesscolorprocessingtime,sotheframerateincreases.Theaccuracyofthecolorflowinformationremainsthesame,however,becausethecolorsectorwidthhasnoimpactonthepacketsize.Widercolorsectorsyieldlowerframerates,whilenarrowercolors...[阅读全文]
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13
(2005-04-20 15:35:47)

FactorsAffectingColorFlowImages:PacketSize
Tocreateablackandwhiteimage,ultrasoundsystemsinterrogateeachscanlineoncefortissueinformation.However,toachieveareliablepictureofcomplexbloodflowmovementovertime,colorflowimagingsystemsmustinterrogateeachcolorscanlineseveraltimesforflowinformation.
Packetsizeisthetermforthenumberoftimestheultrasoundsystemconsecutivelyinterrogateseachcolorscanlinefo...[阅读全文]
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12
(2005-04-20 15:35:00)

FactorsAffectingColorFlowImages:AngleDependency-2
Thefollowingdiagramsillustratethechangesinthecolordisplayastheflowanglebecomesincreasinglyclosertoparallelwiththetransmittedbeam.
Atposition1,whereflowisperpendiculartothebeamofsound,therearenodetectablefrequencyshifts.Blackindicatesaflowvelocityofzero.Atposition2,wheretheangleofincidencebetweenthebeamofsoundandtheflowisslightlymoreparallel...[阅读全文]
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11
(2005-04-20 15:33:12)

FactorsAffectingColorFlowImages
Learningthebasics,suchasdeterminingbloodflowdirection,velocity,aliasing,andlaminarvs.turbulentbloodflow,isjustthefirststepinunderstandingCFI.Next,youmustunderstandotherfactorsthatchangethecolor,sensitivity,andaccuracyoftheimageyousee.Thesefactorsinclude:Angledependency,whichaffectstheaccuracyofthecolorvelocityestimates.Packetsize,whichaffectsnotonlytheaccuracyof...[阅读全文]
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10
(2005-04-20 15:32:00)

ColorFlowImagingBasics:DifferentiatingBloodFlowPatterns
Themulticoloredpatternsquicklymovingacrossthescreencanbequiteconfusingtothelearner.Concentratingonjustonechamberatatime,andinonepartofthecardiaccyclemakesiteasiertoseparatecolorchanges.Forexample,ifyouaretryingtoidentifymitralregurgitationinanapicalfour-chamberview,focusontheleftatriuminsystole,andlookforbloodflowmovingawayfromthetransduc...[阅读全文]
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9
(2005-04-20 15:30:08)

ColorFlowImagingBasics:ColorandM-modeImaging
YoumayalsofindcolorflowimaginghelpfulduringM-modestudies.CFIsuperimposedontheM-modedisplaygivesspecificdetailaboutthetiminganddurationofjets.Inthefollowingexamplethepatienthasbothmitralandaorticinsufficiancy.Aorticinsufficiency(AI),indicatedbythemosaicofcolorsintheleftventricularoutflowtractindiastole,andMitralinsufficiency(MI),indicatedbythemosaico...[阅读全文]
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9
(2005-04-20 15:29:09)

ColorFlowImagingBasics:ColorandM-modeImaging
YoumayalsofindcolorflowimaginghelpfulduringM-modestudies.CFIsuperimposedontheM-modedisplaygivesspecificdetailaboutthetiminganddurationofjets.Inthefollowingexamplethepatienthasbothmitralandaorticinsufficiancy.Aorticinsufficiency(AI),indicatedbythemosaicofcolorsintheleftventricularoutflowtractindiastole,andMitralinsufficiency(MI),indicatedbythemosaico...[阅读全文]
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8
(2005-04-20 15:28:24)

ColorFlowImagingBasics:ScanningTechnique
ColorFlowimaging(CFI)quicklyprovidesatremendousamountofvaluablebloodflowinformation.Examiningeachbloodflowpatterninseveraldifferentimagingviewsallowsamoreaccurateassessmentofbloodflow.

ColorFlowImagingisatwo-dimensionaltechniqueforevaluatingthree-dimensionalbloodflowovertime.Ultrasoundprovidesonlyaverythin“slice”oftheheartatanyon...[阅读全文]
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