1、Solitary pulmonary nodule:benign versus malignant 孤立性肺结节：良性与恶孤立性肺结节：良性与恶性对比性对比 The differential diagnosis of a solitary pulmonary nodule is broad and management depends on whether the lesion is benign or malignant.孤立性肺结节的鉴别诊断是很多的，处理方法依赖于该病变是良性还是恶性 In this overview we will discuss some of the new fea
2、tures that can help to differentiate between benign and malignant nodules based upon CT and PET-CT findings.在此篇文章，我们着重讨论下一些有助于鉴别良恶性结节的新特征，此特征是基于CT与PET-CT的检查结果 CT:benign versus malignant Calcification Size Growth Shape Margin Air Bronchogram sign Solid and Ground-glass components Contrast enhancement
3、 CT:良性与恶性良性与恶性 钙化 大小 生长速度 形状 边缘 支气管含气征 实性或磨玻璃样 增强特征 Calcification 钙化钙化 Diffuse,central,laminated or popcorn calcifications are benign patterns of calcification.弥漫性，中心性，分层，爆米花钙化是良性钙化，These types of calcification are seen in granulomatous disease and hamartomas 这些形式的钙化最常见于错构瘤、肉芽肿性病变 The exception to t
4、he rule above is when patients are known to have a primary tumor.For instance the diffuse calcification pattern can be seen in patients with osteosarcoma or chondrosarcoma.Similarly the central and popcorn pattern can be seen in patients with GI-tumors and patients who previously had chemotherapy.一些
5、病人有原发肿瘤病史，可以表现为良性钙化 例如骨肉瘤、软骨肉瘤可以表现弥漫性钙化。胃肠间质瘤的病人化疗后可以表现为中心性或苞米花钙化。Size 大小大小 A solitary pulmonary nodule(SPN)is defined as a single intraparenchymal lesion 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.孤立性结节定义为小于3
6、cm，不伴有肺不张、淋巴结转移，大于3cm的为肿块 This distinction is made,because lesions greater than 3 cm are usually malignant,while smaller lesions can be either benign or malignant.以3cm为界，因为大于3cm的通常是恶性的，而小于3cm的可能是良性或恶性。Relationship between SPN-size and chance of malignancy in patients with high risk for lung cancer 结
7、节大小与恶性度具有密切相关性结节大小与恶性度具有密切相关性 Growth 生长速度 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 benignity.与前次影像结果相比是鉴别孤立性结节良恶性的一个非常有用的方法。如果超过2年以上保持不变，这个结节就是良性结节 Shape 形态 Japa
8、nese screening studies showed that a polygonal shape and a three-dimensional ratio 1.78 was a sign of benignity(2,3).日本的一项研究表明，多变形和三维立体比率大于1.78是良性结节的标志 A polygonal shape means that the lesion has multiple facets(multi-sided).多边形意味这个病灶具有多个面A peripheral subpleural location was also a sign of benignity
9、 in this study 在这项研究中，周围的胸膜下的病变也是良性结节的一个标志 The three-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 benign sign.Margin 边缘 Corona radi
10、ata sign-highly associated with malignancy(figure)放射冠征 Lobulated or scalloped margins-intermediate probability 分叶征和锯齿征 Smooth margins-more likely benign unless metastatic in origin 边缘光滑见于良性结节，除外转移瘤 Air Bronchogram sign 空气支气管征 Recent studies have showed that an air bronchogram is more commonly seen i
11、n malignant pulmonary nodules.It is most commonly seen in BAC(bronchoalveolar cell carcinoma)and adenocarcinoma.最近一项研究表明，在恶性结节中经常看见空气支气管征，主要见于支气管肺泡癌或腺癌 The case on the left shows an airbronchogram seen as a linear lucency(broad arrow)and as a more cystic lucency(small arrow)due to the fact that the
12、bronchus is seen en face.On the left two solitary pulmonary nodules.Based upon the morphology,which lesion has the most malignant features?下列两个结节有哪些恶性特征呢 The lesion on the far left has a spicuated margin and has lucencies within it.The lesion next to it is lobulated in contour and has some spicules
13、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 adenocarninoma,while the other one was a fungal infection.The lucencies and frank air bronchograms should not mislead y
14、ou in thinking that it probably is infection.Solid and Ground-glass components 实性与磨玻璃样 Another result from screening studies is that nodules containing a ground-glass component are more likely to be malignant(5).另一项研究表明，含有磨玻璃样密度的结节很可能是恶性结节。Partly solid lesions with ground-glass components had a mali
15、gnancy rate of 63%.部分实性和磨玻璃样密度是恶性结节的可能性事63%Nonsolid-only ground-glass lesions had a malignancy rate of 18%.完全磨玻璃样密度结节16%是恶性结节 Only solid lesions had a malignancy rate of only 7%.完全实性结节是仅7%是恶性结节 Partly solid nodule containing ground-glass component most likely to be malignant On the far left a lesion
16、 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 the lesion on the far left and 2:3 for the lesion with both ground-glass and solid components.LEFT:1 in 5 malignant 左边图是5个病灶1个为恶性结节 RIGHT:2 in 3 malignant 右边图是3个病灶2个为恶性结节 Contrast enhancement 对比增强 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 interva
