Radial-EBUS-徑向超聲及其雜交技術(英文版)

RadialEndobronchial

Ultrasound(Radial-EBUS) 徑向超聲Radial-EBUS:For

What?Peripheralpulmonarylesions(PPLs)weredefinedasthosethatweresurroundedbypulmonaryparenchymaandnotvisiblebybronchoscopy(noevidenceofendobronchiallesion,extrinsiccompression,

submucosaltumour,ornarrowing,in?ammationorbleedingofthe

bronchus).PPLsarecommonproblemsinclinicalpractice.Clinicaldataandradiographicfinding,suchaschestradiographyandcomputedtomography(CT)canprovidesomecluesfordiagnosis.However,insomecircumstances,definitediagnosisisrequiredbeforedecidingontheappropriatetreatment.Therefore,respiratoryspecimensareneededtoidentifytheetiologyofthe

lesions.Flexiblebrochoscopy(FB)canreachintotheairwayuptothesubsegmentalbronchi;beyondthevisualrange,theairwaycontinuallydividesintomanygenerationsbeforetheperipheraltargetisreached.Withoutguidance,FBcannotguaranteeanaccuratesamplingattheexactlocationofthePPL.DiagnosticyieldforroutinebronchoscopyforinvestigationofPPL(i.e.lesionsnotendobronchiallyvisible)maybe

＜20%.ThehighestdiagnosticyieldforbronchoscopicevaluationofPPLsappearstobeassociatedwithuseofRadialEndobronchialultrasound(Radial-EBUS).RadialEBUShasa20-MHz(12-30MHzavailable)rotatingtransducerthatcanbeinsertedtogetherwithorwithoutaguidesheath(GS)throughtheworkingchannel

(2.0-2.8mm)ofastandard?exiblebronchoscope.RadialEBUStransducerprobescomeindifferentsizeswithexternaldiametersof

1.4-2.6

mm.EBUS‘Central’probesareutilisedwithballoonsheathsintheproximalairwaysforeitherbronchialwallassessmentortoguideTBNAoflymphnodes.

EBUS‘peripheral’probeswithoutballoonsheathsareusedtoidentifyparenchymallung

lesionsfor

biopsy.EBUSwasfurthercombinedwiththeguide-sheath(GS)technique.BiopsyforcepscoveredwithaGScanbemovedtothelesionsunderEBUSguidance,afterwhichbiopsyandbrushingspecimenscanbesequentiallyobtainedbykeepingtheGSinthe

lesion.1)toconfirmthepreciselocationofPPLsbyEBUSimagingevenwhensuchlesionsarenotvisibleonX-ray?uoroscopy;2)tofacilitateobtainingbiopsyandbrushingspecimensrepeatedlybyleavingtheGSinthePPLs;3)toobtainbiopsyspecimensfromPPLsthatareaccessibleonlythroughtheuseofacuretteviatheGS;4)todecreasebleedingresultingfromtrappingtheGSinthebronchus;and5)toassesstheinternalstructureofPPLs.Points2),3)and4)areadditionalvaluesoftheGStechniqueaboveRadialEBUS

alone.RadialEBUS:Howto

Use?RadialEBUSistypicallyperformedafterstandardbronchoscopicexaminationofthetracheobronchialtree,includingthesubsegmental

bronchi.EBUSwasperformedusinganendoscopicultrasoundsystem(EU-M30S;Olympus,Tokyo,Japan),equippedwitha20-MHzmechanicalradial-typeprobe(XUM-S20-17R;Olympus),havinganexternaldiameterof1.4mm.FBswithaworkingchannelof2.0mmindiameterwereused(BF-P-260F,BF-P-240,BF-P-200;

Olympus).Endobronchialultrasonography(EBUS)-guide-sheath(GS)-guidedtransbronchialbiopsy(TBB).a)EBUSprobewithGSisadvancedtothePPLviaFB.AfterconfirmationbyEBUSimaging,b)theUSprobeispulledout,andc)TBBandbronchialbrushingareperformedviatheGS.WhenthelesionisnotidentifiedbyEBUSimaging,d)acuretteisinsertedintotheGSandtheappropriatebronchusisselected.e)Thecuretteisthenpulledoutandf)theEBUSprobeisagaininsertedintotheGStoperformEBUSimaging.AfterconfirmationbyEBUSimaging,g)TBBandbronchialbrushingareperformed.Pulmonarymasseshaveahypoechoictexturewhencomparedwiththesurroundingtissue,andhavesharplydefinedbordersduetothestrongre?ectiveinterfaceproducedbetweentheaeratedlungandthe

lesions.RadialEBUS,snowstormpatternofnormalEBUSimageinlungperiphery.Radialprobe

endobronchialultrasoundimageindicatingpresenceofperi-bronchialmasslesion.Thepositionoftheprobeisindicatedbythecentralblackcircleandthehyper-echoicline(arrows)demonstratesthesolidtissue–airinterfacebetweentheperibronchialpulmonarymasslesion(P)andthesurroundinglung(L).An82-yr-oldmalewhounderwentrightupperlunglobectomyforpulmonaryadenocarcinomaandwhohadthyroidcarcinoma12yrspreviouslywasadmittedtothestudyhospitalwithanabnormalchestshadow.a)Chestradiographandb)computedtomographyshowedapulmonarynoduleof8mmindiameterintheleftS3a(arrows).c)Endobronchialultrasonographyshowedalowe-choicnodulesurroundedbyastrongreflectedinterfaceproducedbetweentheaeratedlungandthelesion(arrowheads;scalebar=0.5cm).MetastaticadenocarcinomaofthethyroidwasdiagnosedbyEBUS-guide-sheath-guidedtransbronchial

biopsy.Typicalendobronchialultrasonographicimageofasinglesolidpulmonarynodule,inthiscaseanoduleof14mmindiameterintheleftupperlobeofa53-yr-oldmalewithasuspecteddiagnosisoflung

cancer.RadialEBUS,image

oftheperipheralpulmonary

lesion.RadialEBUSimageofthetransducerprobewithinaperipherallunglesionthatwasproventobeadenocarcinomaon

histology.RadialEBUS:The

SensitivityResultsforsensitivityfordetectionofmalignancyinindividualstudiesrangedfrom49%to88%.Thepointsensitivityforpooleddatawas0.73(95%CI

0.70–0.76).Pooledstatisticsdemonstratedadiagnosticyieldof56.3%(95%CI51–61%)and77.7%(95%CI73–82%)forlesions＜=20mm(364patients)andlesions＞20mm(367patients),respectively.RadialEBUS:Complication

RatesComplicationrates

instudies

variedfrom

0% to7.4%.Experiencedonlyminorself-limitingbleeding.Nopatientsinanystudyexperiencedbleedingrequiringintervention.Pneumothoraxratevariedfrom0%to5.1%,withapooledrateofpneumothoraxacrossstudiesof1.0%(11outof1,090).Thepooledrateofintercostalcatheterdrainageofpneumothoraxwas

0.4%.NodeathswerereportedinanyRadialEBUSstudies.RadialEBUS:AdvantagesoverAlternative Techniquesfor

PPLs1.Routine

bronchoscopyDiagnosticyieldforroutinebronchoscopyforinvestigationofPPLs(i.e.lesionsnotendobronchiallyvisible)maybe

＜20%.2.FBunderX-ray?uoroscopicguidanceNodulesof＜20mmindiameteraredifficultorimpossibletovisualisewithfluoroscopicguidance.Thus,forthesenodules,anoveralldiagnosticsensitivityof33%(range5–76%)inameta-analysis.AccuracyofdiagnosingPPLsusingFBunderX-ray?uoroscopicguidanceisreportedly14–71%.Onefactorthatpotentiallylimitsthediagnosticaccuracyofthestandardbronchoscopeislesionsize,aslesions＜2cmhaveverylowyieldsranging11–42%.3.Electromagneticnavigation(EMN)Analternativetofluoroscopicguidanceiselectromagneticnavigation,whichcanguidethebiopsyofperipherallesions.Thereportedsuccessinsamplinglesionsof＜30mmindiameteris

～65%.However,electromagneticnavigationisnotwidelyavailableandrequiresthin-sectioncomputedtomography(CT)forplanningandexpensivedisposables.EMNisanalternateguidancemechanismhoweverit

isveryexpensiveanddiagnosticaccuracyisnotsignificantlybetterthan

EBUS-TBLB.4.CT-guidedpercutaneousneedleaspiration

(CT-PNB)CT-guidedtransthoracicneedleaspirationmayresultinadiagnosisin74–96%ofpatients,againdependingonlesionsize,butisassociatedwithreportedpneumothoraxratesthatrange

15–44%.CT-guidedneedlebiopsyandobservedthatsensitivityfordetectionofmalignancyusingCT-PNBinmoststudiesexceeds90%;however,～20%ofprocedureswerenon-diagnostic,reflectingtheloweryieldofCT-PNBinbenignconditions.4.CT-guidedpercutaneousneedleaspiration

(CT-PNB)AlthoughsuccessratesCT-PNBmightbeveryhigh,with76–97%diagnosticaccuracy,thesetechniqueshaveseveralproblems.First,theyhavethepotentialtospreadmalignantcellsfromthetumourintothepleuralcavity.Forpatientswithpoorpulmonaryfunction,thesetechniquesresultinanincreasedriskofpneumothorax.Moreover,systemicarterialairembolismisararebutsevere

complication.4.CT-guidedpercutaneousneedleaspiration

(CT-PNB)Incomparison,manystudiesdescribingCT-PNBreportpneumothoraxrates~25%,andashighas69%,withmanyofthesepatientsrequiringadmissionorevenintercostalcatheterdrainage.Pulmonaryhaemorrhageislessfrequent,butstillcomplicates1–10%ofCT-PNB.5.RadialEBUS:Initial

procedureWithadditionaluseofaGS,localizationofthelesionhasconsistentlytranslatedtobetterdiagnosticyieldsrangingfrom73to92percent.EBUS-TBLBhasimproveddiagnosticyieldofbronchoscopicinvestigationofPPLstoalevelmorecomparabletoCT-PNB,withimprovementinsensitivitymostapparentforsmallerlesions.5.RadialEBUS:Initial

procedureThemajoradvantageofEBUS-TBLBoverCT-PNBisitssafetyprofile.Ameta-analysisdemonstratedanoverallpneumothoraxrateofjust1.0%,andanoverallintercostaldraininsertionrateof

0.4%.RadialEBUS:

ProspectWithexcellentspecificityandsensitivitymarkedlyhigherthanforroutinebronchoscopy,althoughalittlelowerthanforCT-PNB,anextremelyfavourablesafetyprofileofEBUS-TBLB,supportinginitialinvestigationofpatientswithPPLsusing

EBUS-TBLB.EBUShasthepotentialtobecomepartofstandardbronchoscopybecauseofnegligiblecomplications,improveddiagnosticyieldandshortlearning

curve.RadialEBUS:InfluencingFactorsofSensitivityLesionsize?---Mostimportant,variationinsizeof

PPLs.Lobe?---YAMADAetal.notedahigheryieldforPPLspositionedintherightmiddlelobeandlingularlobe,EBERHARDTetal.notedhigheryieldintherightmiddleandrightlowerlobesandKURIMOTOetal.notedasignificantlyloweryieldfortheapicoposteriorleftupperlobesegment.Malignant?---Highersensitivityfordetectionofmalignantcomparedtobenign

lesions.Probewithinlesion?---Unsurprisingly,identificationofPPLpositionbytheEBUSprobewasassociatedwithhigher

diagnostic.Centralorperipherallesion?---ProximityofPPLtothepulmonaryhilumwasreportedtobeassociatedwithincreaseddiagnostic,alowersensitivityinpleurallybasedorsub-pleurallesions.Numberofsamples?---Notedanimprovedyieldtoaplateauoffive

biopsies.RadialEBUS:Images

PPLsRadialendobronchialultrasoundimagesforground-glassopacitypulmonary

lesionsSincetheintroductionoflow-dosehelicalcomputedtomography(CT)scanningforlungcancerscreening,thefrequencyofdetectingpulmonaryground-glassopacity(GGO)hasbeenabout20%.GGOscommonlyrepresentavarietyofdiseasessuchasinterstitialpneumonia,pulmonarylymphoproliferativedisease,organisingpneumonia,andpre-invasive,minimallyinvasiveormoderately/poorlydifferentiated

carcinoma.RadialEBUS

imagesTheR-EBUSimagesofGGOswerenamedblizzardormixed

blizzard.Blizzard

signTheblizzardsignwasdefinedasasubtle,butnoticeableincreaseintheintensityandradiusofthewhitishacousticshadowwhilescanningfromnormallungtissuetotheground-glassarea.ThischangeintheultrasoundsignalissimilartoawhiteoutandhasarelativelylargerradiusfromthecentreoftheprobecomparedwiththeR-EBUSsnowstormappearancegeneratedwhilescanningtheareaofnormalalveolartissue.Onmeticulousinspection,thedetailsthatconstitutetheacousticsignalarerelativelythickandcrudecomparedwiththedetailsthatconstitutetherefinedsnowstormappearanceofnormallungtissue.Mixedblizzard

signInthemixedblizzardsigntheinternalechoofthelesionsdemonstrateddiffuseheterogeneitywithseveralhyperechoicdots,lineararcsandvesselsthatweredistributedirregularlyorcombinedwiththeblizzard

sign.Blizzardsign--

mechanismsBlizzardsignontheR-EBUSimagewasconsistentlyobservedinlesionswithmoreGGOcomponent.Themechanismbehindthischangeisdiffractionphenomenon.PureandGGO-dominantlesionsdemonstratethispatternonR-EBUS(blizzard)andthiscouldbeexplainedbythelargeamountofresidualairintheintactalveoli(withoutstromal

invasion).Mixedblizzardsign--

mechanismsThemixedblizzardsignontheR-EBUSimagewasnotfoundinanypureGGOlesion,butwasconsistentlyobservedinlesionswithalargerproportionofsolidcomponent.Allblizzardlesionswereonthespectrumofadenocarcinomainsitutowell-differentiatedadenocarcinoma,whilethemajorityofmixedblizzardlesionswerewell-differentiatedinvasivelepidic-predominantandmoderatelytopoorlydifferentiatedadenocarcinoma.Thissignal,mixedblizzard,mayrepresenttumourinvasionbeyondthealveolarspaces,whichusuallyhappenswhenaGGOlesiondevelopsasolid

component.Mixedblizzardsign--

mechanismsTheultrasoundimagecanbeeasilyrecognizedbecauseitappearshypoechoiccomparedwiththesnowstormappearanceofnormallungandcanbeexplainedbythedifferenceinthemediumthroughwhichtheultrasoundwavewaspropagated(i.e.,air-filledalveolarspaceversusalveolarspacewithlessornoair).TheGGOcomponentthatusuallysurroundstheperipheryofapart-solidlesioncorrespondstotheareathatgeneratesablizzardsignalintheR-EBUS

image.a)Normallung.b)Asubtle,butnoticeableincreaseintheintensityandradiusofthewhitishacousticshadow(blizzardsign).c)Mixedblizzardsign,adiffuselyheterogenousacousticshadow(withsomehyperechoicdots,lineararcsandvessels)thatisdistributedirregularlywithina

blizzard.Arepresentativecaseina74-year-oldwomanwithpureground-glassopacity(GGO)intherightupperlobe.a)Thin-sectioncomputedtomographyscanshowingapureGGOintherightS3b.b)Radialendobronchialultrasound(EBUS)showedasubtlebutnoticeableincreaseintheintensityand

radiusofthewhitishacousticshadow(blizzardsign).c)Real-timefluoroscopyimageofthechestduringradialEBUSscanning.d)Histopathologicalspecimenfromtransbronchialbiopsyshowingcuboidaltumourcellsliningtheentrappedalveolarspace.e)Histopathologicalspecimenfromsurgicalbiopsyshowingawell-differentiatedmicroinvasiveadenocarcinoma.Arepresentativecaseina80-year-oldmanwithapartsolidground-glassopacity(GGO)intheleftlowerlobe.a)Thin-sectioncomputedtomographyscanshowingapartsolidGGOintheleftS10a.b)Radialendobronchialultrasound(EBUS)showingmixedblizzardsign,adiffuseheterogeneity(withsomehyperechoicdots,lineararcsandvessels)thatisdistributed

irregularlywithinablizzard.c)Real-timefluoroscopyimageofthechestduringradialEBUSscanning.d)Histopathologicalspecimenfromthetransbronchialbiopsyshowingadenocarcinomawithlepidicgrowthpattern.e)Histopathologicalspecimenfromthesurgicalbiopsyshowingawelldifferentiatedinvasivelepidic-predominantadenocarcinoma.ItisimportanttonotethattheR-EBUSimagedependsonwhichpartofthelesiontheprobeisin.EBUSgeneratesanacousticshadowfromtheareatheprobetouches.IftheprobeisinabronchusthatisclosetotheGGOportiontheR-EBUSimagewillshowblizzard.Bycontrast,iftheprobeisinabronchusthatisclosetothesolidportiontheR-EBUSimagewillshowmixed

blizzard.EBUS-GSvs.

CT-PNBComparativeeffectivenessofradialprobeendobronchialultrasoundversusCT-guidedneedlebiopsyforevaluationofperipheralpulmonarylesions:Arandomizedpragmatictrial.Allpatientswerereviewedinamultidisciplinarymeeting(MDM)toensurethatconsensusopinionisthatinvestigationiswarrantedandthateitherCT-PNBorEBUSwouldbeacceptablemodesofinitialinvestigationofthelesion.Clinicianscouldexcludepatientsfromthestudyifclinicalacumen(onthebasisofclinicoradiologicfeatures)suggestedahigherdiagnosticaccuracyorlowercomplicationsrateforoneofthetwoprocedures,thusmakingthealternateprocedureunacceptable.Clinicianswereabletoexcludepatientsfromrandomizationiftheyfelttherewasanundulyhighriskofcomplicationsassociatedwithoneprocedure.TwopatientsweredeclinedfromCT-PNBbyinterventionalradiologistsonthebasisofahighriskofcomplicationssuggestedbyradiologic

appearances.CTchestdemonstratesaleftupperlobenoduleadjacenttoanemphysematousbullus,suggestingahighriskofpneumothorax.B)CT/PETdemonstratesFDG-avidlesionwithintheleftupperlobeabuttingtheaorticarch,raisingconcernregardingofvasculartraumacomplicatingtheprocedure.Performanceof

EBUS-TBLBPerformanceof

CT-PNBDiagnosticaccuracywassimilarforbothEBUS-TBLBandCTPNB(87.5%v.93.3%respectively,p=1.0).thereforeourresultsindicatethatEBUS-TBLBisnon-inferiortoCT-PNBforthediagnosisof

PPLs.Therewasasignificantdifferenceintheoverallcomplicationratebetweenthegroups(EBUS3%v.CT-PNB27%,p=

0.03).OurfindingssuggestthatdiagnosticaccuracyofEBUS-TBLBinevaluationofPPLisnon-inferiortoCT-PNB.However,clinicoradiologic

factorsin?uencingdiagnosticaccuracyandcomplicationratesshouldallowclinicianstodeterminewhichprocedureismostappropriateastheinitialinvestigationforindividualpatients.ComplicationratesfollowingEBUS-TBLBaresignificantlylowerthanfollowingCT-PNBandasaresult,ifexpecteddiagnosticsensitivityisequivalent,patientsshouldbepreferentiallyreferredforEBUS-TBLBforinvestigationof

PPL.InEBUS:Centralvs.

PeripheralEndobronchialultrasoundwithaguidesheathforsmallmalignantpulmonarynodules:aretrospectivecomparisonbetweencentralandperipheral

locations.PPNwasdefinedasanabnormal

lungparenchymallesionmeasuring≤30mminlargestdiameteronaxialplaneCTscanandthatwasnotvisibleendoscopically.CTscancharacteristicswereclassifiedassolidorgroundglassopacity(GGO).Locationinthepulmonaryparenchymawasdecidedbasedonapreviousstudyandwasdesignatedas“centralparenchymal”ifthenodulewasnotadjacenttothecostal

visceralpleura;or“peripheralparenchymal”ifthe

nodulewasadjacentto,orwithin10mmfromthecostalvisceralpleura.Thisone-yearstudyon212smallmalignantPPNsdemonstratedthatTBBwithEBUS-GShasanoveralldiagnosticperformanceof67.5percentandmajoritywereadenocarcinoma.Therewerenomajorpost-proceduralcomplications.Thediagnosticyieldforcentralparenchymallesionswassignificantlyhigherthanthatforperipheralparenchymallesions(77%vs.55%,P=0.001).Intheunivariateanalysis,lesionswhereintheEBUSprobecouldbeplacedwithinhadasignificantlyhigherdiagnosticyieldcomparedtowhentheEBUSprobewasadjacentorinvisible(68%vs.54%,P=0.001).Inthemultivariateanalysis,centralparenchymallocationandEBUSprobewithinwerethepredictorsofasuccessful

TBB.Inaddition,thediagnosticyieldforcentralparenchymalwasatleast75%andsignificantlyhigherthanthatofperipheralparenchymalwhenthelesionwas<20mminsize,solidonCTscan,locatedintheupperandlowerlobes,andwhenasmallsizeGSkitwasused.Accuracyoftheprocedureforlesionsthatweretouchingthevisceralpleurawasonly35-50

percent.A43-year-oldmanwithasmallsolidcentralparenchymalnodule.(A)

CTscanshoweda14-mmlesionintherightsegment3thatwaslocalizedby;(B)heterogenousechogenicity,withinonradialEBUS;(C)TBBwithalargeguidesheathkitunderfluoroscopyguidanceyielded;(D)adenocarcinoma(hematoxylin-eosin

stain,×4).A79-year-oldmanwithasmall,part-solidground-glassopacitycentralparenchymalnodule.(A)CTscanshoweda15-mmlesionintherightsegment4thatwaslocalizedby;(B)Blizzardsignonradial

EBUS;(C)TBBwithalarge

guidesheathkitunderfluoroscopyguidanceyielded;(D)adenocarcinoma(hematoxylin-eosin

stain,×10).EBUS-GS+Virtualbronchoscopicnavigation(VBN,DirectPath)+Ultrathin

(P-260F)VirtualBronchoscopicNavigationImprovestheDiagnosticYieldofRadial-EndobronchialUltrasoundforPeripheralPulmonaryLesionswithInvolvedBronchion

CT.Virtualbronchoscopicnavigation(VBN)isamethodinwhichvirtualbronchoscopy(VB)imagesofthebronchialpathtotheperipherallesionareproducedandusedasaguidetonavigatethebronchoscope.Inordertoconfirmthearrivalofthebronchoscopeatthelesionsite,itisnecessarytocombineVBNwithanotherprocedure.Forinstance,thecombinationofVBNand

EBUS-GSTheper-protocolpopulation(194cases)oftheVBNcombinedwithEBUSRCTwasdividedintosubgroupsbasedonthelesionsize,lunglobecontainingthelesion,lesionlocation,presenceorabsenceofinvolvedbronchi(bronchussign)onthin-sectionCTandwhetherthelesionwasdetectedonposterioranterior(P-A)radiographs.ThedifferenceinthediagnosticyieldbetweentheVBN-assisted(VBNA)andnon-VBN-assisted(NVBNA)groupswasinvestigated.Regardingthepresenceorabsenceofthebronchussign,withinthebronchussign-positivesubgroup,thediagnosticyieldintheVBNAandNVBNAgroupswas94.4%and77.8%,respectively,showingasignificantlyhigheryieldintheVBNA

group.Inthebronchussign-negativesubgroup,thediagnosticyieldwasnotsignificantlydifferentbetweenthetwogroups.Inaddition,therewerenosignificantdifferencesinthediagnosticyieldbetweentheVBNAandNVBNAgroupsinanyofthesubgroupsintermsofthelunglobecontainingthelesion,lesionlocationandwhetherthelesionwasdetectedonP-Aradiographs.Withinthebronchussign-positivesubgroup,thediagnosticyieldwassignificantlyhigherintheVBNAgroupamongthepatientswithalesionsizeof<20mm(94.6%vs.70.7%;p=0.006;oddsratio:7.2;95%CI:1.5-35.0),lesionslocatedintheperipheralthirdofthelungfield(95.1%vs.71.4%;p=0.005;oddsratio:7.8;95%CI:1.6-38.6)andinvisiblelesionsonP-Aradiographs(90.0%vs.41.7%;p=0.026;oddsratio:12.6;95%CI:1.2-133.9).Therewerenosignificantdifferencesinthediagnosticyieldbetweenthetwogroupsforanyother

items.Inconclusion,VBNimprovesthediagnosticyieldwhencombinedwithR-EBUSforlesionsshowinginvolvedbronchionCTimages.AsEBUSisrecommendedaccordingtotheACCPguidelines,thenumberofcasesinwhichthistechniqueisappliedmayincrease.VBNshouldbeactivelyusedtoassesslesionsexhibitinginvolvedbronchi,particularlylesionssmallerthan20mmandthoselocatedintheperipheralthirdofthelungfieldand/orinvisibleonP-Aradiographsduetothehighdiagnosticyieldofthis

modality.EBUS-GS+Virtualbronchoscopicnavigation(VBN,LungPoint)+Ultrathin

(P-260F)Diagnosticyieldofcombinedbronchoscopyandendobronchialultrasonography,underLungPointguidanceforsmallperipheralpulmonary

lesions.TheLungPointVBNSystem(hereafterreferredtoas‘LungPoint’;BroncusTechnologies,Inc.,MountainView,CA,USA)combinesanewVBNsystemandcomputer-assistedimage-basednavigationsoftware;itenablesnavigationtoalocalizedareaofinterestinthelung.Supineposition;180mASeff,120kV;collimation,

16×0.75mm;pitch,0.95;1-mmslicethickness,0.5-mmincrement;andtheB70falgorithm.Scanswereperformedattotallungcapacity(inspiratorybreath-hold)sothatthesmallerairwayswere

expanded.TheCTstudywasdirectlysentandimportedintotheLungPointsystemacrossournetwork,andtheimageswereautomatically