孤立性肺結(jié)節(jié)PET-CT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：http://www.radiologyassistant.nl/en/460f9fcd50637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(zhǎng)速度形狀邊界充氣支氣管征實(shí)性和磨玻璃成分強(qiáng)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(shí)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?yàn)榇笥?cm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,nonewasmalignant生長(zhǎng)速度與以前的CT片進(jìn)行比較，在結(jié)節(jié)定性方面具有重要意義。超過2年無變化的結(jié)節(jié)多為良性。形狀左：橫斷圖像；右：冠狀重建圖像。三維比值=（最大）橫徑/長(zhǎng)徑日本的相關(guān)研究證實(shí)，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(zhǎng)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。邊緣輻射冠征：絕大多數(shù)都為惡性（上圖：惡性病灶周圍的輻射冠征--毛刺）。病灶邊緣呈分葉狀的，可以是良性或惡性邊緣光滑，多為良性。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(xì)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(xì)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.圖中兩個(gè)SPN，根據(jù)形態(tài)表現(xiàn)，哪個(gè)更像惡性的？左邊的結(jié)節(jié)邊緣呈毛刺狀，內(nèi)部有透亮區(qū)；右側(cè)者呈分葉狀，邊緣毛刺并與胸膜粘連，但是內(nèi)部均質(zhì)?；谏厦娴谋憩F(xiàn)，我們認(rèn)為左側(cè)者更像惡性的。最終證實(shí)，左側(cè)者為腺癌，右側(cè)為真菌感染。Onthelefttwosolitarypulmonarynodules.

Baseduponthemorphology,whichlesionhasthemostmalignantfeatures?Thelesiononthefarlefthasaspicuatedmarginandhaslucencieswithinit.

Thelesionnexttoitislobulatedincontourandhassomespiculesradiatingtothepleura.

Itishoweverhomogeneousinattenuation.

Basedonthesefindingsweshouldbemostconcernedthatthelesiononthefarleftismalignant.

Itprovedtobeanadenocarcinoma,whiletheotheronewasafungalinfection.

Thelucenciesandfrankairbronchogramsshouldnotmisleadyouinthinkingthatitprobablyisinfection.實(shí)性和磨玻璃成分一項(xiàng)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(shí)性成分，又含有磨玻璃成分的，為惡性的可能性為63%。沒有實(shí)性成分，只有磨玻璃成分的，惡性可能性有18%。全部為實(shí)性成分的，惡性可能性為7%。左側(cè)者只有磨玻璃成分；右側(cè)者既有磨玻璃成分又含有實(shí)性成分。左側(cè)者惡性可能性為1/5;右側(cè)者惡性可能性為2/3.Onthefarleftalesionthatonlyhasaground-glassappearanceandnexttoitalesionthathasbothground-glassandsolidcomponents.

Thelikelihoodofmalignancyis1:5forthelesiononthefarleftand2:3forthelesionwithbothground-glassandsolidcomponents.ContrastenhancementContrastenhancementlessthan15HUhasaveryhighpredictivevalueforbenignity(99%).

Afterabaselinescan,4consecutivescansat1minuteintervalareperformed.

Thisappliesonlyfornoduleswiththefollowingselectioncriteria:Nodule>5mmRelativelysphericalHomogeneous,nonecrosis,fatorcalcificationNomotionorbeamhardeningartifactsPET-CTPET-CT在實(shí)性結(jié)節(jié)評(píng)價(jià)方面起著越來越重要的作用。在進(jìn)行PET-CT檢查時(shí)，你必須意識(shí)到：PET-CT敏感性高達(dá)95%，但特異性只有81%；肉芽腫性疾病可以呈假陽(yáng)性；小于10mm的結(jié)節(jié)、良性腫瘤以及低度惡性的結(jié)節(jié)包括支氣管肺泡癌可以呈假陰性。上圖為一例腺癌病人，結(jié)節(jié)并不顯示為高代謝狀態(tài)，所以呈假陰性。結(jié)論在良惡性肺結(jié)節(jié)的鑒別診斷中，我們要尤其注意以下影像學(xué)特征：磨玻璃征、充氣支氣管征及結(jié)節(jié)的三維比值。在進(jìn)行PET-CT檢查時(shí)，要注意PET-CT的準(zhǔn)確性問題，要注意感染性或非感染性肉芽腫性疾病診斷的可能性。ConclusionInthedifferentiationofbenignversusmalignantsolitarypulmonarynodulesnowadaysnewimagingfeatureshavetobeadded.

Weespeciallyhavetolookforthepresenceofareasofground-glassopacity,airbronchogramsorcaviti