孤立性肺结节PET-CT良恶性鉴别诊断教学内容.ppt

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1、孤立性肺结节PET-CT良恶性鉴别诊断孤立性肺结节的鉴别诊断，在临床中经常遇到。根据结节的良恶性差异，处理方法有很大差别。在这篇文章中，我们主要探讨CT和PET-CT的相关征象在孤立性肺结节良恶性鉴别诊断中的意义。n nThe differential diagnosis of a solitary pulmonary nodule is broad and The differential diagnosis of a solitary pulmonary nodule is broad and management depends on whether the lesion is beni

2、gn or malignant.management depends on whether the lesion is benign or malignant.In this overview we will discuss some of the new features that can help to In this overview we will discuss some of the new features that can help to differentiate between benign and malignant nodules based upon CT and d

3、ifferentiate between benign and malignant nodules based upon CT and PET-CT findings PET-CT findings 结节大小 结节大小与恶性可能性之间的关系结节大小与恶性可能性之间的关系n n孤立性肺结节（孤立性肺结节（SPNSPN）定义：肺实质内小于等于）定义：肺实质内小于等于3cm3cm的病灶（需除外的病灶（需除外肺不张和肿大的淋巴结）。大于肺不张和肿大的淋巴结）。大于3cm3cm的病灶称为肿块（的病灶称为肿块（massmass）。）。n n之所以这样定义，是因为大于之所以这样定义，是因为大于3cm3cm的

4、病灶多为恶性，而更小的病灶可的病灶多为恶性，而更小的病灶可能是良心或恶性。能是良心或恶性。n nSwensen.et al Swensen.et al 研究了研究了SPNSPN大小与恶性可能性之间的关系（上图），大小与恶性可能性之间的关系（上图），结论是小的结节，良性可能性大。超过结论是小的结节，良性可能性大。超过20002000例小于例小于4mm4mm的结节，无的结节，无一例属于恶性。一例属于恶性。Size n nA solitary pulmonary nodule(SPN)is defined as a single A solitary pulmonary nodule(SPN)is

5、defined as a single intraparenchymal lesion less than 3 cm in size and not intraparenchymal lesion less than 3 cm in size and not associated with atelectasis or lymphadenopathy.associated with atelectasis or lymphadenopathy.A lesion greater than 3 cm in diameter is called a mass.A lesion greater tha

6、n 3 cm in diameter is called a mass.This distinction is made,because lesions greater than 3 cm This distinction is made,because lesions greater than 3 cm are usually malignant,while smaller lesions can be either are usually malignant,while smaller lesions can be either benign or malignant.benign or

7、malignant.n nSwensen et al studied the relationship between the size of a Swensen et al studied the relationship between the size of a SPN and the chance of malignancy in a cohort at high risk SPN and the chance of malignancy in a cohort at high risk for lung cancer(1).for lung cancer(1).Their findi

8、ngs are listed in the table on the left.Their findings are listed in the table on the left.They concluded that benign nodule detection rate is high,They concluded that benign nodule detection rate is high,especially if lesions are small.especially if lesions are small.Of the over 2000 nodules that w

9、ere less than 4 mm in size,Of the over 2000 nodules that were less than 4 mm in size,none was malignantnone was malignant生长速度n n与以前的CT片进行比较，在结节定性方面具有重要意义。超过2年无变化的结节多为良性。Growthn nComparison with prior imaging studies is often the most useful procedure to determine the importance of the finding of a S

10、PN,since stability over 2 years is highly associated with benignity.形状 左：横断图像；右：冠状重建图像。三维比值左：横断图像；右：冠状重建图像。三维比值=（最大）横径（最大）横径/长径长径n n日本的相关研究证实，多角形、三维比值大于日本的相关研究证实，多角形、三维比值大于1.781.78的结节，多为的结节，多为良性。在肺的外围、胸膜下的结节也多为良性。良性。在肺的外围、胸膜下的结节也多为良性。n n三维比值三维比值=（最大）横径（最大）横径/长径。大的三维比值说明病灶的形状是长径。大的三维比值说明病灶的形状是扁平的（是扁平

11、的（是“片片”不是不是“块块”），这是良性的特征。），这是良性的特征。Shapen nJapanese screening studies showed that a Japanese screening studies showed that a polygonal shape and a three-dimensional ratio polygonal shape and a three-dimensional ratio 1.78 was a sign of benignity(2,3).1.78 was a sign of benignity(2,3).A polygonal sha

12、pe means that the lesion has A polygonal shape means that the lesion has multiple facets(multi-sided).multiple facets(multi-sided).A peripheral subpleural location was also a sign of A peripheral subpleural location was also a sign of benignity in this study.benignity in this study.n nThe three-dime

13、nsional ratio is measured by The three-dimensional ratio is measured by obtaining the maximal transverse dimension and obtaining the maximal transverse dimension and dividing it by the maximal vertical dimension.dividing it by the maximal vertical dimension.A large three-dimensional ratio indicates

14、that the A large three-dimensional ratio indicates that the lesion is relatively flat,which is a benign sign.lesion is relatively flat,which is a benign sign.边缘n n辐射冠征辐射冠征辐射冠征辐射冠征：绝大多数都为恶性（上图：恶性病灶：绝大多数都为恶性（上图：恶性病灶周围的辐射冠征周围的辐射冠征-毛刺）。毛刺）。n n病灶边缘呈病灶边缘呈分叶状分叶状分叶状分叶状的，可以是良性或恶性的，可以是良性或恶性n n边缘边缘光滑光滑光滑光滑，多为良

15、性。，多为良性。Marginn nCorona radiata sign-highly associated with malignancy(figure)n nLobulated or scalloped margins-intermediate probability n nSmooth margins-more likely benign unless metastatic in origin 充气支气管征n n最新研究表明，有充气支气管征的结节多为恶性。最新研究表明，有充气支气管征的结节多为恶性。主要见于主要见于BACBAC（细支气管肺泡癌）和腺癌。（细支气管肺泡癌）和腺癌。n n上图

16、显示充气的支气管呈线样（粗箭）或囊状上图显示充气的支气管呈线样（粗箭）或囊状（细箭）透亮区，这是支气管走向不同造成的。（细箭）透亮区，这是支气管走向不同造成的。Air Bronchogram signn nRecent studies have showed that an air Recent studies have showed that an air bronchogram is more commonly seen in bronchogram is more commonly seen in malignant pulmonary nodules.malignant pulmona

17、ry nodules.It is most commonly seen in BAC It is most commonly seen in BAC(bronchoalveolar cell carcinoma)and(bronchoalveolar cell carcinoma)and adenocarcinoma.adenocarcinoma.n nThe case on the left shows an The case on the left shows an airbronchogram seen as a linear lucency airbronchogram seen as

18、 a linear lucency(broad arrow)and as a more cystic(broad arrow)and as a more cystic lucency(small arrow)due to the fact that lucency(small arrow)due to the fact that the bronchus is seen en face.the bronchus is seen en face.n n图中两个图中两个SPNSPN，根据形态表现，哪个更像恶性的？，根据形态表现，哪个更像恶性的？n n左边的结节边缘呈毛刺状，内部有透亮区；右侧者呈分

19、叶左边的结节边缘呈毛刺状，内部有透亮区；右侧者呈分叶状，边缘毛刺并与胸膜粘连，但是内部均质。状，边缘毛刺并与胸膜粘连，但是内部均质。n n基于上面的表现，我们认为左侧者更像恶性的。最终证实，基于上面的表现，我们认为左侧者更像恶性的。最终证实，左侧者为腺癌，右侧为真菌感染。左侧者为腺癌，右侧为真菌感染。n nOn the left two solitary pulmonary nodules.On the left two solitary pulmonary nodules.Based upon the morphology,which lesion has the Based upon th

20、e morphology,which lesion has the most malignant features?most malignant features?n nThe lesion on the far left has a spicuated margin The lesion on the far left has a spicuated margin and has lucencies within it.and has lucencies within it.The lesion next to it is lobulated in contour and The lesio

21、n next to it is lobulated in contour and has some spicules radiating to the pleura.has some spicules radiating to the pleura.It is however homogeneous in attenuation.It is however homogeneous in attenuation.Based on these findings we should be most Based on these findings we should be most concerned

22、 that the lesion on the far left is concerned that the lesion on the far left is malignant.malignant.It proved to be an adenocarcinoma,while the It proved to be an adenocarcinoma,while the other one was a fungal infection.other one was a fungal infection.The lucencies and frank air bronchograms shou

23、ld The lucencies and frank air bronchograms should not mislead you in thinking that it probably is not mislead you in thinking that it probably is infection.infection.实性和磨玻璃成分一项研究表明：结节内含有磨玻璃样成分的，更倾向于属于恶性。结节内既含有部分实性成分，又含有磨玻璃成结节内既含有部分实性成分，又含有磨玻璃成分的，为恶性的可能性为分的，为恶性的可能性为63%63%。没有实性成分，只有磨玻璃成分的，恶性可能没有实性成分，

24、只有磨玻璃成分的，恶性可能性有性有18%18%。全部为实性成分的，恶性可能性为全部为实性成分的，恶性可能性为7%7%。Solid and Ground-glass componentsAnother result from screening studies is that Another result from screening studies is that nodules containing a ground-glass nodules containing a ground-glass component are more likely to be component are mo

25、re likely to be malignant.malignant.Partly solid lesions with ground-glass Partly solid lesions with ground-glass components had a malignancy rate of 63%.components had a malignancy rate of 63%.Nonsolid-only ground-glass lesions had a Nonsolid-only ground-glass lesions had a malignancy rate of 18%.m

26、alignancy rate of 18%.Only solid lesions had a malignancy rate of Only solid lesions had a malignancy rate of only 7%.only 7%.n n左侧者只有磨玻璃成分；右侧者既有磨玻璃成分左侧者只有磨玻璃成分；右侧者既有磨玻璃成分又含有实性成分。又含有实性成分。n n左侧者恶性可能性为左侧者恶性可能性为1/5;1/5;右侧者恶性可能性为右侧者恶性可能性为2/3.2/3.n nOn the far left a lesion that only has a ground-glass a

27、ppearance and next to it a lesion that has both ground-glass and solid components.The likelihood of malignancy is 1:5 for the lesion on the far left and 2:3 for the lesion with both ground-glass and solid components.强化特征n n增强扫描强化程度小于增强扫描强化程度小于15HU15HU的，有的，有99%99%的可能性为良性。的可能性为良性。平扫后增强扫描，每一分钟扫描一次，连续平扫

28、后增强扫描，每一分钟扫描一次，连续4 4次。次。n n结节满足以下条件者，才能采用这种方法评价：结节满足以下条件者，才能采用这种方法评价：结节结节5mm5mm 相对呈球形相对呈球形 内部均质，没有坏死、脂肪和钙化内部均质，没有坏死、脂肪和钙化 图像无明显伪影图像无明显伪影Contrast enhancement n nContrast enhancement less than 15 HU Contrast enhancement less than 15 HU has a very high predictive value for has a very high predictive va

29、lue for benignity(99%).benignity(99%).After a baseline scan,4 consecutive scans After a baseline scan,4 consecutive scans at 1 minute interval are performed.at 1 minute interval are performed.This applies only for nodules with the This applies only for nodules with the following selection criteria:f

30、ollowing selection criteria:Nodule 5mm Nodule 5mm Relatively spherical Relatively spherical Homogeneous,no necrosis,fat or calcification Homogeneous,no necrosis,fat or calcification No motion or beam hardening artifacts No motion or beam hardening artifacts PET-CTn nPET-CTPET-CT在实性结节评价方面起着越来越重要的作用。在

31、实性结节评价方面起着越来越重要的作用。n n在进行在进行PET-CTPET-CT检查时，你必须意识到：检查时，你必须意识到：PET-CTPET-CT敏感性高达敏感性高达95%95%，但特异性只有，但特异性只有81%81%；肉芽肿性疾病可以呈假阳性；肉芽肿性疾病可以呈假阳性；小于小于10mm10mm的结节、良性肿瘤以及低度恶性的结节包括支气管肺的结节、良性肿瘤以及低度恶性的结节包括支气管肺泡癌可以呈假阴性。泡癌可以呈假阴性。n n上图为一例腺癌病人，结节并不显示为高代谢状态，所以上图为一例腺癌病人，结节并不显示为高代谢状态，所以呈假阴性。呈假阴性。PET-CT:benign versus mal

32、ignant n nPET-CT plays an increasingly important role in the PET-CT plays an increasingly important role in the evaluation of solitary nodules.evaluation of solitary nodules.n nWhen you perform PET-CT,you have to realize When you perform PET-CT,you have to realize the following:the following:PET has

33、 a very high sensitivity 95%,but a lesser specificity of PET has a very high sensitivity 95%,but a lesser specificity of only 81%only 81%PET is false positive in granulomatous disease PET is false positive in granulomatous disease PET is usually false negative in size 10 mm and low-grade PET is usua

34、lly false negative in size 10 mm and low-grade malignancy including bronchoalveolar carcinoma and carcinoid malignancy including bronchoalveolar carcinoma and carcinoid n nWith these specificity numbers,there will be false With these specificity numbers,there will be false positives in about 20%,dep

35、ending on the positives in about 20%,depending on the background prevalence of granulomatous disease.background prevalence of granulomatous disease.On the left a patient with an adenocarcinoma,On the left a patient with an adenocarcinoma,that was not hypermetabolic on the PET,so it is a that was not

36、 hypermetabolic on the PET,so it is a false negative PET.false negative PET.结论n n在良恶性肺结节的鉴别诊断中，我们要尤其注意以下影像学特征：磨玻璃征、充气支气管征及结节的三维比值。n n在进行PET-CT检查时，要注意PET-CT的准确性问题，要注意感染性或非感染性肉芽肿性疾病诊断的可能性。Conclusionn nIn the differentiation of benign versus malignant In the differentiation of benign versus malignant s

37、olitary pulmonary nodules nowadays new solitary pulmonary nodules nowadays new imaging features have to be added.imaging features have to be added.We especially have to look for the presence of We especially have to look for the presence of areas of ground-glass opacity,air bronchograms areas of gro

38、und-glass opacity,air bronchograms or cavities and the three-dimensional ratios of a or cavities and the three-dimensional ratios of a lesion.lesion.n nWith the increasingly important role of PET-CT,With the increasingly important role of PET-CT,we have to be aware of the accuracy of PET-CT we have

39、to be aware of the accuracy of PET-CT and we should have an idea about the prevalence and we should have an idea about the prevalence of infectious and non-infectious granulomatous of infectious and non-infectious granulomatous disease in the area that we practice.disease in the area that we practice.