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(2005-04-20 15:50:07)

NormalBloodFlow:NormalBloodFlowThroughtheTricuspidValve
Youcanseebloodflowthroughthetricuspidvalveintheparasternal,apical,andsubcostalviews.Normalrightventricularinflowoccursindiastole,asbloodmovesfromtherightatrium(RA)totheRV.
DiastolicflowthroughthetricuspidvisualizeseasilyintheparasternalRVinflowview.Anenhancedvelocitymapisused.Thislaminarbloodflow,movingalmostdirectlytowardthetransduce...[阅读全文]
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(2005-04-20 15:49:25)

NormalBloodFlow:NormalBloodFlowThroughtheAorticValve
Theparasternalandapicalviewsshowbloodflowthroughtheaorticvalve.Normalleftventricularoutflow(LVOT)occursinsystole,asbloodmovesfromtheleftventricletotheaorta.
Thissystolicparasternallong-axisviewshowsnormalLVOT.Anenhancedvelocitymapisused.Sincethebloodflowismovingonlyslightlytowardthetransducer,itispredominantlydarkred.Thelaminarbloodflowh...[阅读全文]
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(2005-04-20 15:47:46)

BloodFlowPatternsintheHeart:Normal
Normalbloodflowisusuallylaminar,characterizedbyasmoothhomogeneouscolorpattern.AliasingwilloccurifthevelocitiesexceedtheNyquistlimit.Youcanimagenormalbloodflowfromanywindowthatletsyouseebothproximalanddistaltoavalve.
NormalBloodFlow:NormalBloodFlowThroughtheMitralValve
Youcanseebloodflowthroughthemitralvalve(MV)fromtheparasternal,apicalandsubcostalview...[阅读全文]
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(2005-04-20 15:46:27)
FactorsAffectingColorFlowImages:Summary
Angledependencyaffectstheaccuracyofthecolorvelocityinformationdisplayed.Asbloodflowbecomesparalleltothesoundbeam,theultrasoundsystemcalculatesmoreaccuratevelocityestimates.Asbloodflowbecomesmoreperpendiculartothesoundbeam,lessaccurate,lower-than-actualvelocityestimatesarecalculated.Largerpacketsizesoffergreatervelocityaccuracy,butproducelowerframerates.S...[阅读全文]
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(2005-04-20 15:45:05)

FactorsAffectingColorFlowImages:TransducerFrequency
Asthetransducerfrequencyincreases,themaximummeasurablemeanvelocity(determinedbytheNyquistlimit)decreases.Selectinglowerfrequencytransducersincreasesmeanvelocitymeasurementcapabilityatanygivendepth.
'Yourbrowserisnotsetuptorunthisapplication.PleasedownloadandinstalltheFlash6Player.Getithere.[阅读全文]
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(2005-04-20 15:44:11)

FactorsAffectingColorFlowImages:Clutter(Wall)Filters
Alongeachcolorscanlinethecoloralgorithmreceivesfrequencyshiftsfrommovingtissueaswellasfromblood.Assigningcolortomovinganatomicstructureshelpsultrasounddistinguishmovingstructuresfrommovingblood.Thiscoloringonanatomicstructuresiscalled“ghosting”or“flashing".Tominimizeflashingultrasoundsystemsemployclutterfilters(alsocalledwallfilters).Thec...[阅读全文]
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(2005-04-20 15:42:48)

FactorsAffectingColorFlowImages:ColorGain
Youcanadjusttheamountofcolorinanimageusingthecolorgaincontrol.Aproperlyadjustedcolorgaincontrolletsyouseealltheavailablecolorinformation.Selectingacolorgainsettingthatistolowpreventdetectionanddisplayoflowamplitudesignals.Bloodflowpatternsappearsmallerthantheyreallyaresincethelowsamplitudesignals,attheedgesofthejet,arenotvisible.

...[阅读全文]
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(2005-04-20 15:41:45)

ColorMaps:VarianceMaps
Variancemapsindicatethepresenceofturbulentflow,aswellasthedegreeofturbulence.Agreenoverlayindicatesturbulenceacrossthestandardred/bluevelocitycolorbar,fromlefttoright.Greaterturbulenceresultsintheadditionofmoregreen.Inavariancemap,normal,laminarbloodflowappearsaseitherredorblue,dependingonitsdirection.Non-laminarbloodflowisindicatedbyanycolorotherthanredorblue.
Youre...[阅读全文]
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(2005-04-20 15:40:40)

ColorMaps:EnhancedVelocityMaps
Theexamplesinthefirstsectionofthistutorialusedanenhancedvelocitymap.Enhancedvelocitycolormapsdisplaybloodflowmovingtowardthetransducerwithredschangingtoyellowswithvelocityincreases.Bloodflowmovingawayfromthetransducerisdisplayedwithdarkbluesthatgraduallychangetolightbluesasthevelocitiesincrease.Themanycolorsinthismapletyoumoreeasilydistinguishbetweendifferentmean...[阅读全文]
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(2005-04-20 15:39:58)

FactorsAffectingColorFlowImages:ColorMaps
Colormaps,thepatternsofcolorsonthecolorbar,canhelpyoudetectvariousbloodflowcharacteristics.Somecolormapshighlightdifferencesinvelocity,whileothershighlightturbulence.Thefollowingexamplesallusetheredtoward,blueawayformat.Remember,youcanchangethetoward/awaycolororientation.
ColorMaps:StandardRed/BlueMaps
Withstandardred/bluemaps,redsrepresentbloo...[阅读全文]
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