孤立性肺結(jié)節(jié)petct良惡性鑒別診斷課件

孤立性肺結(jié)節(jié)

CT、PET-CT良惡性鑒別診斷Solitarypulmonarynodule:benignversusmalignant

DifferentiationwithCTandPET-CTAnnLeungandRobinSmithuis原文地址：孤立性肺結(jié)節(jié)的鑒別診斷，在臨床中經(jīng)常遇到。根據(jù)結(jié)節(jié)的良惡性差異，處理方法有很大差別。

在這篇文章中，我們主要探討CT和PET-CT的相關(guān)征象在孤立性肺結(jié)節(jié)良惡性鑒別診斷中的意義。Thedifferentialdiagnosisofasolitarypulmonarynoduleisbroadandmanagementdependsonwhetherthelesionisbenignormalignant.

InthisoverviewwewilldiscusssomeofthenewfeaturesthatcanhelptodifferentiatebetweenbenignandmalignantnodulesbaseduponCTandPET-CTfindings目錄（contents）CT征象鈣化大小生長速度形狀邊界充氣支氣管征實性和磨玻璃成分強化特征PET-CT征象結(jié)論CT:benignversusmalignantCalcification

SizeGrowth

Shape

Margin

AirBronchogramsign

SolidandGround-glasscomponents

Contrastenhancement

PET-CT:benignversusmalignantConclusion

CalcificationDiffuse,central,laminatedorpopcorncalcificationsarebenignpatternsofcalcification.

Thesetypesofcalcificationareseeningranulomatousdiseaseandhamartomas.

Allotherpatternsofcalcificationshouldnotberegardedasasignofbenignity.Theexceptiontotheruleaboveiswhenpatientsareknowntohaveaprimarytumor.

Forinstancethediffusecalcificationpatterncanbeseeninpatientswithosteosarcomaorchondrosarcoma.

SimilarlythecentralandpopcornpatterncanbeseeninpatientswithGI-tumorsandpatientswhopreviouslyhadchemotherapy.結(jié)節(jié)大小

結(jié)節(jié)大小與惡性可能性之間的關(guān)系孤立性肺結(jié)節(jié)（SPN）定義：肺實質(zhì)內(nèi)小于等于3cm的病灶（需除外肺不張和腫大的淋巴結(jié)）。大于3cm的病灶稱為腫塊（mass）。之所以這樣定義，是因為大于3cm的病灶多為惡性，而更小的病灶可能是良心或惡性。Swensen.etal研究了SPN大小與惡性可能性之間的關(guān)系（上圖），結(jié)論是小的結(jié)節(jié)，良性可能性大。超過2000例小于4mm的結(jié)節(jié)，無一例屬于惡性。SizeAsolitarypulmonarynodule(SPN)isdefinedasasingleintraparenchymallesionlessthan3cminsizeandnotassociatedwithatelectasisorlymphadenopathy.

Alesiongreaterthan3cmindiameteriscalledamass.

Thisdistinctionismade,becauselesionsgreaterthan3cmareusuallymalignant,whilesmallerlesionscanbeeitherbenignormalignant.SwensenetalstudiedtherelationshipbetweenthesizeofaSPNandthechanceofmalignancyinacohortathighriskforlungcancer(1).

Theirfindingsarelistedinthetableontheleft.

Theyconcludedthatbenignnoduledetectionrateishigh,especiallyiflesionsaresmall.

Oftheover2000nodulesthatwerelessthan4mminsize,nonewasmalignantGrowthComparisonwithpriorimagingstudiesisoftenthemostusefulproceduretodeterminetheimportanceofthefindingofaSPN,sincestabilityover2yearsishighlyassociatedwithbenignity.形狀

左：橫斷圖像；右：冠狀重建圖像。三維比值=（最大）橫徑/長徑日本的相關(guān)研究證實，多角形、三維比值大于1.78的結(jié)節(jié)，多為良性。在肺的外圍、胸膜下的結(jié)節(jié)也多為良性。三維比值=（最大）橫徑/長徑。大的三維比值說明病灶的形狀是扁平的（是“片”不是“塊”），這是良性的特征。ShapeJapanesescreeningstudiesshowedthatapolygonalshapeandathree-dimensionalratio>1.78wasasignofbenignity(2,3).

Apolygonalshapemeansthatthelesionhasmultiplefacets(multi-sided).

Aperipheralsubpleurallocationwasalsoasignofbenignityinthisstudy.Thethree-dimensionalratioismeasuredbyobtainingthemaximaltransversedimensionanddividingitbythemaximalverticaldimension.

Alargethree-dimensionalratioindicatesthatthelesionisrelativelyflat,whichisabenignsign.MarginCoronaradiatasign-highlyassociatedwithmalignancy(figure)Lobulatedorscallopedmargins-intermediateprobabilitySmoothmargins-morelikelybenignunlessmetastaticinorigin充氣支氣管征最新研究表明，有充氣支氣管征的結(jié)節(jié)多為惡性。主要見于BAC（細支氣管肺泡癌）和腺癌。上圖顯示充氣的支氣管呈線樣（粗箭）或囊狀（細箭）透亮區(qū)，這是支氣管走向不同造成的。AirBronchogramsignRecentstudieshaveshowedthatanairbronchogramismorecommonlyseeninmalignantpulmonarynodules.

ItismostcommonlyseeninBAC(bronchoalveolarcellcarcinoma)andadenocarcinoma.Thecaseontheleftshowsanairbronchogramseenasalinearlucency(broadarrow)andasamorecysticlucency(smallarrow)duetothefactthatthebronchusisseenenface.Onthelefttwosolitarypulmonarynodules.

Baseduponthemorphology,whichlesionhasthemostmalignantfeatures?Thelesiononthefarlefthasaspicuatedmarginandhaslucencieswithinit.

Thelesionnexttoitislobulatedincontourandhassomespiculesradiatingtothepleura.

Itishoweverhomogeneousinattenuation.

Basedonthesefindingsweshouldbemostconcernedthatthelesiononthefarleftismalignant.

Itprovedtobeanadenocarcinoma,whiletheotheronewasafungalinfection.

Thelucenciesandfrankairbronchogramsshouldnotmisleadyouinthinkingthatitprobablyisinfection.實性和磨玻璃成分一項研究表明：結(jié)節(jié)內(nèi)含有磨玻璃樣成分的，更傾向于屬于惡性。結(jié)節(jié)內(nèi)既含有部分實性成分，又含有磨玻璃成分的，為惡性的可能性為63%。沒有實性成分，只有磨玻璃成分的，惡性可能性有18%。全部為實性成分的，惡性可能性為7%。SolidandGround-glasscomponentsAnotherresultfromscreeningstudiesisthatnodulescontainingaground-glasscomponentaremorelikelytobemalignant.

Partlysolidlesionswithground-glasscomponentshadamalignancyrateof63%.Nonsolid-onlyground-glasslesionshadamalignancyrateof18%.Onlysolidlesionshadamalignancyrateofonly7%.Onthefarleftalesionthatonlyhasaground-glassappearanceandnexttoitalesionthathasbothground-glassandsolidcomponents.

Thelikelihoodofmalignancyis1:5forthelesiononthefarleftand2:3forthelesionwithbothground-glassandsolidcomponents.強化特征增強掃描強化程度小于15HU的，有99%的可能性為良性。平掃后增強掃描，每一分鐘掃描一次，連續(xù)4次。結(jié)節(jié)滿足以下條件者，才能采用這種方法評價：結(jié)節(jié)>5mm相對呈球形內(nèi)部均質(zhì)，沒有壞死、脂肪和鈣化圖像無明顯偽影ContrastenhancementContrastenhancementlessthan15HUhasaveryhighpredictivevalueforbenignity(99%).

Afterabaselinescan,4consecutivescansat1minuteintervalareperformed.

Thisappliesonlyfornoduleswiththefollowingselectioncriteria:Nodule>5mmRelativelysphericalHomogeneous,nonecrosis,fatorcalcificationNomotionorbeamhardeningartifactsPET-CT:benignversusmalignantPET-CTplaysanincreasinglyimportantroleintheevaluationofsolitarynodules.Whenyouper