NormalBloodFlow:NormalBloodFlowThroughtheTricuspidValve
Youcanseebloodflowthroughthetricuspidvalveintheparasternal,apical,andsubcostalviews.Normalrightventricularinflowoccursindiastole,asbloodmovesfromtherightatrium(RA)totheRV.
DiastolicflowthroughthetricuspidvisualizeseasilyintheparasternalRVinflowview.Anenhancedvelocitymapisused.Thislaminarbloodflow,movingalmostdirectlytowardthetransduce...[
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NormalBloodFlow:NormalBloodFlowThroughtheAorticValve
Theparasternalandapicalviewsshowbloodflowthroughtheaorticvalve.Normalleftventricularoutflow(LVOT)occursinsystole,asbloodmovesfromtheleftventricletotheaorta.
Thissystolicparasternallong-axisviewshowsnormalLVOT.Anenhancedvelocitymapisused.Sincethebloodflowismovingonlyslightlytowardthetransducer,itispredominantlydarkred.Thelaminarbloodflowh...[
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BloodFlowPatternsintheHeart:Normal
Normalbloodflowisusuallylaminar,characterizedbyasmoothhomogeneouscolorpattern.AliasingwilloccurifthevelocitiesexceedtheNyquistlimit.Youcanimagenormalbloodflowfromanywindowthatletsyouseebothproximalanddistaltoavalve.
NormalBloodFlow:NormalBloodFlowThroughtheMitralValve
Youcanseebloodflowthroughthemitralvalve(MV)fromtheparasternal,apicalandsubcostalview...[
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FactorsAffectingColorFlowImages:Summary
Angledependencyaffectstheaccuracyofthecolorvelocityinformationdisplayed.Asbloodflowbecomesparalleltothesoundbeam,theultrasoundsystemcalculatesmoreaccuratevelocityestimates.Asbloodflowbecomesmoreperpendiculartothesoundbeam,lessaccurate,lower-than-actualvelocityestimatesarecalculated.Largerpacketsizesoffergreatervelocityaccuracy,butproducelowerframerates.S...[
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FactorsAffectingColorFlowImages:TransducerFrequency
Asthetransducerfrequencyincreases,themaximummeasurablemeanvelocity(determinedbytheNyquistlimit)decreases.Selectinglowerfrequencytransducersincreasesmeanvelocitymeasurementcapabilityatanygivendepth.
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FactorsAffectingColorFlowImages:Clutter(Wall)Filters
Alongeachcolorscanlinethecoloralgorithmreceivesfrequencyshiftsfrommovingtissueaswellasfromblood.Assigningcolortomovinganatomicstructureshelpsultrasounddistinguishmovingstructuresfrommovingblood.Thiscoloringonanatomicstructuresiscalled“ghosting”or“flashing".Tominimizeflashingultrasoundsystemsemployclutterfilters(alsocalledwallfilters).Thec...[
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FactorsAffectingColorFlowImages:ColorGain
Youcanadjusttheamountofcolorinanimageusingthecolorgaincontrol.Aproperlyadjustedcolorgaincontrolletsyouseealltheavailablecolorinformation.Selectingacolorgainsettingthatistolowpreventdetectionanddisplayoflowamplitudesignals.Bloodflowpatternsappearsmallerthantheyreallyaresincethelowsamplitudesignals,attheedgesofthejet,arenotvisible.
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ColorMaps:VarianceMaps
Variancemapsindicatethepresenceofturbulentflow,aswellasthedegreeofturbulence.Agreenoverlayindicatesturbulenceacrossthestandardred/bluevelocitycolorbar,fromlefttoright.Greaterturbulenceresultsintheadditionofmoregreen.Inavariancemap,normal,laminarbloodflowappearsaseitherredorblue,dependingonitsdirection.Non-laminarbloodflowisindicatedbyanycolorotherthanredorblue.
Youre...[
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ColorMaps:EnhancedVelocityMaps
Theexamplesinthefirstsectionofthistutorialusedanenhancedvelocitymap.Enhancedvelocitycolormapsdisplaybloodflowmovingtowardthetransducerwithredschangingtoyellowswithvelocityincreases.Bloodflowmovingawayfromthetransducerisdisplayedwithdarkbluesthatgraduallychangetolightbluesasthevelocitiesincrease.Themanycolorsinthismapletyoumoreeasilydistinguishbetweendifferentmean...[
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FactorsAffectingColorFlowImages:ColorMaps
Colormaps,thepatternsofcolorsonthecolorbar,canhelpyoudetectvariousbloodflowcharacteristics.Somecolormapshighlightdifferencesinvelocity,whileothershighlightturbulence.Thefollowingexamplesallusetheredtoward,blueawayformat.Remember,youcanchangethetoward/awaycolororientation.
ColorMaps:StandardRed/BlueMaps
Withstandardred/bluemaps,redsrepresentbloo...[
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