医学影像学 放射科 (1) 学习资料

Solitarypulmonarynodule:

benignversusmalignantDifferentiationwithCT

良性VS.恶性孤立性肺结节CT鉴别Thedifferentialdiagnosisofasolitarypulmonarynoduleisbroadandmanagementdependsonwhetherthelesionisbenignormalignant.

WewilldiscusssomeofthefeaturesthatcanhelptodifferentiatebetweenbenignandmalignantnodulesbaseduponCT.孤立性肺结节的鉴别诊断内容宽泛，治疗措施依赖于病变的良恶性。我们将讨论CT所见上良恶性结节的一些特征以资鉴别诊断。CT：良性VS.恶性钙化大小生长形状边缘空气支气管征（支气管气相）实性和毛玻璃样成分对比增强结论CT:benignversusmalignantCalcificationSizeGrowthShapeMarginAirBronchogramsignSolidandGround-glasscomponentsContrastenhancementConclusionCalcification钙化

Diffuse,central,laminatedorpopcorncalcificationsarebenignpatternsofcalcification.

Thesetypesofcalcificationareseeningranulomatousdiseaseandhamartomas.

弥漫性，中心性，层状或爆米花样钙化是钙化的良性类型。

Allotherpatternsofcalcificationshouldnotberegardedasasignofbenignity.

其他类型的钙化不应认为是良性病变的征象。

Theexceptiontotheruleaboveiswhenpatientsareknowntohaveaprimarytumor.

Forinstancethediffusecalcificationpatterncanbeseeninpatientswithosteosarcomaorchondrosarcoma.

如果已知病患罹患原发性肿瘤则上述规律可有例外。比如，弥漫性钙化可见于骨肉瘤或软骨肉瘤的患者。

SimilarlythecentralandpopcornpatterncanbeseeninpatientswithGI-tumorsandpatientswhopreviouslyhadchemotherapy.

同样，中心性和爆米花样钙化可见于胃肠道肿瘤患者和以前做过化疗的患者。Size大小

Asolitarypulmonarynodule(SPN)isdefinedasasingleintraparenchymallesionlessthan2cminsizeandnotassociatedwithatelectasisorlymphadenopathy.

孤立性肺结节的定义是单发、病变大小小于2厘米并且不伴有肺不张或淋巴结肿大。

Alesiongreaterthan2cmindiameteriscalledamass.

病变直径大于2厘米叫做肿块。

Thisdistinctionismade,becauselesionsgreaterthan2cmareusuallymalignant,whilesmallerlesionscanbeeitherbenignormalignant.

做这种区别是因为大于2厘米的病变常常是恶性的，而较小的病变可以是良性的或恶性的。

SwensenetalstudiedtherelationshipbetweenthesizeofaSPNandthechanceofmalignancyinacohortathighriskforlungcancer.Swensen等研究了一组肺癌高风险患者孤立性肺结节大小与恶性病变发生几率间的关系。

Theirfindingsarelistedinthetableontheleft.其所见列于左侧表内。

Theyconcludedthatbenignnoduledetectionrateishigh,especiallyiflesionsaresmall.

Oftheover2000nodulesthatwerelessthan4mminsize,nonewasmalignant.他们的结论是良性病变检出率高尤其是病变较小时。超过2000个结节中小于4毫米的结节无一例是恶性。肺结节，最大横截面1.7cm×1.4cmGrowth生长ComparisonwithpriorimagingstudiesisoftenthemostusefulproceduretodeterminetheimportanceofthefindingofaSPN,sincestabilityover2yearsishighlyassociatedwithbenignity.

与原先图像进行对比常常是判定孤立性肺结节所见重要性的最有效方法。因为稳定超过两年的病变高度指向良性病变。肺结节一年后随访对比图片Shape形状Japanesescreeningstudiesshowedthatapolygonalshapeandathree-dimensionalratio>1.78wasasignofbenignity.

日本人筛查研究显示多边形和三维之比大于1.78是良性病变征象。

Apolygonalshapemeansthatthelesionhasmultiplefacets(multi-sided).

多边形意味着病变有多个小面（多边）。

Aperipheralsubpleurallocationwasalsoasignofbenignityinthisstudy.

此项研究中胸膜下肺外周部位也是良性病变的征象。

Thethree-dimensionalratioismeasuredbyobtainingthemaximaltransversedimensionanddividingitbythemaximalverticaldimension.

三维比是指最大横径除以最大垂径。

Alargethree-dimensionalratioindicatesthatthelesionisrelativelyflat,whichisabenignsign.较大的三维比提示病变相对扁平，是一种良性征象。Margin边缘

Coronaradiatasign

-highlyassociatedwithmalignancy(figure)Lobulatedorscallopedmargins

-intermediateprobabilitySmoothmargins

-morelikelybenignunlessmetastaticinorigin辐射征高度指向恶性病变（图示）分叶形或圆顿锯齿形边缘良恶性概率居中平滑边缘更可能是良性除非是原发部位的转移AirBronchogramsign支气管气相

Recentstudieshaveshowedthatanairbronchogramismorecommonlyseeninmalignantpulmonarynodules.最近研究表明支气管气相较常见于恶性肺结节。

ItismostcommonlyseeninBAC(bronchoalveolarcellcarcinoma)andadenocarcinoma.

此征象最常见于BAC（支气管肺泡细胞癌）和腺癌。

Thecaseontheleftshowsanairbronchogramseenasalinearlucency(broadarrow)andasamorecysticlucency(smallarrow)duetothefactthatthebronchusisseenenface.

左侧病例示支气管气相，表现为线样腔隙（宽箭）和囊状腔隙（小箭）是迎面看到的支气管。Onthelefttwosolitarypulmonarynodules.

Baseduponthemorphology,whichlesionhasthemostmalignantfeatures?Thelesiononthefarlefthasaspiculatedmarginandhaslucencieswithinit.

Thelesionnexttoitislobulatedincontourandhassomespiculesradiatingtothepleura.

Itishoweverhomogeneousinattenuation.

Basedonthesefindingsweshouldbemostconcernedthatthelesiononthefarleftismalignant.

Itprovedtobeanadenocarninoma,whiletheotheronewasafungalinfection.

Thelucenciesandfrankairbronchogramsshouldnotmisleadyouinthinkingthatitprobablyisinfection.左侧两个孤立性肺结节。根据形态，那个具备最多恶性特征？最左侧病变有锯齿样边缘其内有透光影。另一个轮廓上有分叶，近胸膜处可见少许锯齿样改变。但是密度均匀。基于这些表现，我们会认为最左侧是恶性的。实际证明是一例腺癌，另一例是真菌感染。透亮影或直接说是支气管气相不应误导你认为可能是感染。SolidandGround-glasscomponents

实性和磨玻璃样成分Partlysolidlesionswithground-glasscomponentshadamalignancyrateof63%.部分为实性部分为磨玻璃样成分的恶性率约63%Nonsolid-onlyground-glasslesionshadamalignancyrateof18%.没有实性成分仅磨玻璃样成分的恶变率约18%Onlysolidlesionshadamalignancyrateofonly7%.只有实性成分的恶变率约7%whichlesionhasthemostmalignantfeatures?

Contrastenhancement对比增强

Contrastenhancementlessthan15HUhasaveryhighpredictivevalueforbenignity(99%).

Afterabaselinescan,4consecutivescan