Solitary pulmonary nodule: benign versus malignant 孤立性肺结节：良性与恶 性对比nThe differential diagnosis of a solitary pulmonary nodule is broad and management depends on whether the lesion is benign or malignant.n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 features that can help to differentiate between benign and malignant nodules based upon CT and PET-CT findings.n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 malignantnCalcification nSize nGrowth nShape nMargin nAir Bronchogram sign nSolid and Ground-glass components nContrast enhancement CT:良性与恶性n钙化n大小n生长速度n形状n边缘n支气管含气征n实性或磨玻璃样n增强特征Calcification 钙化nDiffuse, central, laminated or popcorn calcifications are benign patterns of calcification. n弥漫性，中心性，分层，爆米花钙化是良性 钙化，nThese types of calcification are seen in granulomatous disease and hamartomasn这些形式的钙化最常见于错构瘤、肉芽肿 性病变nThe 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 osteosarcoma or chondrosarcoma. Similarly the central and popcorn pattern can be seen in patients with GI-tumors and patients who previously had chemotherapy.n一些病人有原发肿瘤病史，可以表现为良性钙化n例如骨肉瘤、软骨肉瘤可以表现弥漫性钙化。n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nA 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3cm，不伴有肺不张、淋巴 结转移，大于3cm的为肿块nThis distinction is made, because lesions greater than 3 cm are usually malignant, while smaller lesions can be either benign or malignant. n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 结节大小与恶性度具有密切相关性Growth 生长速度nComparison 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.n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nJapanese 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nA 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 in this study n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nThe 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nCorona radiata sign - highly associated with malignancy (figure) 放射冠征nLobulated or scalloped margins - intermediate probability 分叶征和锯齿征nSmooth margins - more likely benign unless metastatic in origin n边缘光滑见于良性结节，除外转移瘤Air Bronchogram sign 空气支气管征nRecent studies have showed that an air bronchogram is more commonly seen in malignant pulmonary nodules. It is most commonly seen in BAC (bronchoalveolar cell carcinoma) and adenocarcinoma.n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nThe 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 bronchus is seen en face.nOn the left two solitary pulmonary nodules. Based upon the morphology, which lesion has the most malignant features? n下列两个结节有哪些恶性特征呢nThe 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 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 you in thinking that it probably is infection. Solid and Ground-glass components 实性与磨玻璃样nAnother result from screening studies is that nodules containing a ground-glass component are more likely to be malignant (5).n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。nPartly solid lesions with ground-glass components had a malignancy 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%nNonsolid - 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nOnly solid lesions had a malignancy rate of only 7%.完全实性结 节是仅7%是恶性结节nPartly solid nodule containing ground-glass component most likely to be malignantnOn 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 the lesion on the far left and 2:3 for the lesion with both ground-glass and solid components.nLEFT: 1 in 5 malignant 左边图是5个病灶1个为恶性结节nRIGHT: 2 in 3 malignantn右边图是3个病灶2个为恶性结节Contrast enhancement 对比增强nContrast enhancement less than 15 HU h