孤立性肺結節(jié)petct良惡性鑒別診斷

1、孤立性肺結節(jié)的鑒別診斷，在臨床中經(jīng)常遇到。根據(jù)結節(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的相關征象在孤立性肺結節(jié)良惡性鑒別診斷中的意義。,The differential diagnosis of a solitary pulmonary nodule is broad and management depends on whether the lesion is benign or malig

2、nant.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 PET-CT findings,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

3、征PET-CT征象結論,CT: benign versus malignant Calcification Size Growth Shape Margin Air Bronchogram sign Solid and Ground-glass components Contrast enhancement PET-CT: benign versus malignant Conclusion,鈣化,良性鈣化征象

4、： 彌漫性 中心性 層狀 爆米花樣彌漫性、中心性、層狀及爆米花樣鈣化多見于良性結節(jié)。主要見于肉芽腫性疾病和錯構瘤。其他類型鈣化多見于惡性結節(jié)，不應該認為屬于良性表現(xiàn)。在已知有原發(fā)腫瘤存在的情況下，其鈣化類型不一定適用此結論。例如：骨肉瘤或軟骨肉瘤的病人，其鈣化多表現(xiàn)為彌漫性；同樣的，中心性和爆米花樣鈣化也可見于胃腸道腫瘤或接受過化療

5、的病人。,Calcification,Diffuse, central, laminated or popcorn calcifications are benign patterns of calcification.These types of calcification are seen in granulomatous disease and hamartomas.All other patterns of calcific

6、ation should not be regarded as a sign of benignity.The exception to the rule above is when patients are known to have a primary tumor.For instance the diffuse calcification pattern can be seen in patients with osteosa

7、rcoma or chondrosarcoma.Similarly the central and popcorn pattern can be seen in patients with GI-tumors and patients who previously had chemotherapy.,結節(jié)大小,結節(jié)大小與惡性可能性之間的關系孤立性肺結節(jié)（SPN）定義：肺實質內小于等于3cm的病灶（需除外肺不張和腫大的淋巴結）。大于

8、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. et al 研究了SPN大小與惡性可能性之間的關系（上圖），結論是小的結節(jié)，良性可能性大。超過2000例小于4mm的結節(jié)，無一例屬于惡性。,Size,A solitary pulmonary nodule (SPN) is defined as a single intraparenchymal lesi

9、on less than 3 cm in size and not associated with atelectasis or lymphadenopathy.A lesion greater than 3 cm in diameter is called a mass.This distinction is made, because lesions greater than 3 cm are usually malignant

10、, while smaller lesions can be either benign or malignant.Swensen et al studied the relationship between the size of a SPN and the chance of malignancy in a cohort at high risk for lung cancer (1).Their findings are li

11、sted in the table on the left.They concluded that benign nodule detection rate is high, especially if lesions are small.Of the over 2000 nodules that were less than 4 mm in size, none was malignant,生長速度,與以前的CT片進行比較，在結節(jié)

12、定性方面具有重要意義。超過2年無變化的結節(jié)多為良性。,Growth,Comparison with prior imaging studies is often the most useful procedure to determine the importance of the finding of a SPN, since stability over 2 years is highly associated with benig

13、nity.,形狀,左：橫斷圖像；右：冠狀重建圖像。三維比值=（最大）橫徑/長徑日本的相關研究證實，多角形、三維比值大于1.78的結節(jié)，多為良性。在肺的外圍、胸膜下的結節(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。,Shape,Japanese screening studies showed that a polygonal shape and a three

14、-dimensional ratio > 1.78 was a sign of benignity (2,3).A polygonal shape means that the lesion has multiple facets (multi-sided).A peripheral subpleural location was also a sign of benignity in this study.The thre

15、e-dimensional ratio is measured by obtaining the maximal transverse dimension and dividing it by the maximal vertical dimension.A large three-dimensional ratio indicates that the lesion is relatively flat, which is a be

16、nign sign.,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。,Margin,Corona radiata sign - highly associated with malignancy (figure) Lobulated or scalloped margins - intermediate probability Smooth ma

17、rgins - more likely benign unless metastatic in origin,充氣支氣管征,最新研究表明，有充氣支氣管征的結節(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。,Air Bronchogram sign,Recent studies have showed that an air bronchogram i

18、s more commonly seen in malignant pulmonary nodules.It is most commonly seen in BAC (bronchoalveolar cell carcinoma) and adenocarcinoma.The case on the left shows an airbronchogram seen as a linear lucency (broad arrow

19、) and as a more cystic lucency (small arrow) due to the fact that the bronchus is seen en face.,圖中兩個SPN，根據(jù)形態(tài)表現(xiàn)，哪個更像惡性的？左邊的結節(jié)邊緣呈毛刺狀，內部有透亮區(qū)；右側者呈分葉狀，邊緣毛刺并與胸膜粘連，但是內部均質。基于上面的表現(xiàn)，我們認為左側者更像惡性的。最終證實，左側者為腺癌，右側為真菌感染。,On the left

20、two solitary pulmonary nodules.Based upon the morphology, which lesion has the most malignant features?The lesion on the far left has a spicuated margin and has lucencies within it. The lesion next to it is lobulated

21、in contour and has some spicules radiating to the pleura.It is however homogeneous in attenuation.Based on these findings we should be most concerned that the lesion on the far left is malignant.It proved to be an ade

22、nocarcinoma, while the other one was a fungal infection.The lucencies and frank air bronchograms should not mislead you in thinking that it probably is infection.,實性和磨玻璃成分,一項研究表明：結節(jié)內含有磨玻璃樣成分的，更傾向于屬于惡性。結節(jié)內既含有部分實性成分，又含有

23、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%。,Solid and Ground-glass components,Another result from screening studies is that nodules containing a ground-glass component are more likely to be malignan

24、t.Partly solid lesions with ground-glass components had a malignancy rate of 63%. Nonsolid - only ground-glass lesions had a malignancy rate of 18%. Only solid lesions had a malignancy rate of only 7%.,左側者只有磨玻璃成分；右側者

25、既有磨玻璃成分又含有實性成分。左側者惡性可能性為1/5;右側者惡性可能性為2/3.,On the far left a lesion that only has a ground-glass appearance and next to it a lesion that has both ground-glass and solid components.The likelihood of malignancy is 1:5 for

26、 the lesion on the far left and 2:3 for the lesion with both ground-glass and solid components.,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。結節(jié)滿足以下條件者，才能采用這種方法評價：結節(jié)>5mm相對呈球形內部均質，沒有壞死、脂肪和鈣化圖像無明顯偽影,Contra

27、st enhancement,Contrast enhancement less than 15 HU has a very high predictive value for benignity (99%).After a baseline scan, 4 consecutive scans at 1 minute interval are performed.This applies only for nodules with

28、 the following selection criteria: Nodule > 5mm Relatively spherical Homogeneous, no necrosis, fat or calcification No motion or beam hardening artifacts,PET-CT,PET-CT在實性結節(jié)評價方面起著越來越重要的作用。在進行PET-CT檢查時，你必須意識到：PET-