表现为磨玻璃密度影的细支气管肺泡癌与非典型腺瘤样增生的CT鉴别诊断

目的分析58例表现为肺单纯性磨玻璃密度结节(pGGO)的细支气管肺泡癌(BAC)与非典型腺瘤样增生(AAH)的薄层螺旋CT表现。方法回顾性分析经病理证实的薄层螺旋CT扫描的40例BAC和19例AAH资料,分析其病灶大小(直径)和薄层螺旋CT表现:如病灶形态、边缘形态、内部结构、邻近结构等。统计学方法用χ2检验进行分析。结果薄层螺旋CT所示病变直径、球形度和空泡征对鉴别BAC和AAH最有意义,两者之间均有统计学差异(P均<0.05)。结论较小的球形结节多是AAH。空泡征多见于BAC。     

亚实性结节肺腺癌的研究进展

【摘要】亚实性结节即磨玻璃密度结节（GGN）作为一个非特异性征象,可以出现在非典型腺瘤样增生（AAH）、原位腺癌（AIS）、腺癌和良性病变（如炎症、局部纤维化、局灶性肺出血）等多种病理状态下。GGN的良恶性鉴别诊断主要依靠其生长特性、密度、形态特征和影像组学技术等。计算机辅助诊断（CAD）已初步应用于肺结节良恶性的判别。本文对GGN的相关研究及CAD进展进行综述。     

低剂量MSCT对肺部磨玻璃结节的定性诊断

目的：探讨低剂量螺旋CT对肺部磨玻璃结节（GGN）性质的诊断价值。方法：回顾性分析87例肺部低剂量CT检出的GGN，将病灶分为浸润前病变组（34例）、肺腺癌组（53例）。对2组病灶的大小、实性成分、病灶边界、边缘毛刺、分叶、空泡征、血管集束征及胸膜凹陷征等进行对比分析。结果：87例中纯磨玻璃结节（pGGN）36例，混合磨玻璃结节（mGGN）51例。浸润前病变组主要表现为pGGN（28/34，82.35%），肺腺癌组主要表现为mGGN（45/53，84.90%）；浸润前病变最大径平均值（11.18±2.68）mm，肺腺癌为（16.43±3.36）mm，2组差异均有统计学意义（均P<0.001）。2组GGN中实性成分、毛刺、分叶比较差异均有统计学意义（均P<0.05）；而2组病灶边界是否清晰、空泡征、血管集束征、胸膜凹陷征比较差异均无统计学意义（均P>0.05）。结论：低剂量螺旋CT对肺部GGN性质的判断具有重要临床价值。     

CT密度直方图对肺内纯磨玻璃样结节病理分级的预测价值

目的探讨CT密度直方图定量分析对肺内纯磨玻璃样结节(pGGN)病理分级的预测价值。方法回顾分析经手术病理证实CT表现为pGGN的肺腺癌126例,共128个pGGN病灶的CT影像及病理资料。所有患者均行CT平扫,CT密度直方图定量分析pGGN中密度参数差异所包含的诊断信息,包括平均CT值、最小CT值、最大CT值、中位CT值、偏度、峰度。按有无浸润分为浸润前病变(包括AAH+AIS)和浸润性病变(包括MIA+IAC)两组,其中不典型腺瘤样增生(AAH)23个、原位腺癌(AIS)34个、微浸润性腺癌(MIA)31个、浸润性腺癌(IAC)40个。采用独立样本t检验比较浸润前病变和浸润性病变之间pGGN密度参数的差异。采用ROC评价pGGN密度指标鉴别浸润前病变和浸润性病变的效能。结果浸润前病变与浸润性病变之间pGGN密度指标(平均CT值、最大CT值、偏度、峰度)差异有统计学意义(P<0.05);最小CT值、中位CT值差异无统计学意义(P>0.05)。pGGN CT密度直方图参数中,最大CT值鉴别浸润前病变与浸润性病变的ROC下面积最大为0.89(P<0.001),是pGGN为浸润性病变的危险因素;最大CT值鉴别诊断的敏感性最高(95.8%);偏度特异性最高(96.5%)。结论CT密度直方图得到pGGN的平均CT值、最大CT值、偏度、峰度密度差异指标对pGGN的病理分级具有一定的预测作用。     

肺腺癌的能谱CT参数与肿瘤浸润性及 Ki-67表达的相关性研究

目的：探究能谱CT成像参数与肺腺癌病理上的浸润性及Ki-67表达的相关性。材料与方法：收集我院2016年3月至2017年 7月经手术病理证实为肺腺癌患者的资料,共计60例,免疫组化均包含Ki-67,术前均已行宝石能谱成像（Gemstone spectral imaging,GSI）扫描。其中纯磨玻璃结节（pGGN）15例、混合磨玻璃结节（mGGN）组15例、实性结节组30例,采用spearman相关分析分别比较三组结节动、静脉期IC和Ki-67抗原表达的相关性。其中30例磨玻璃结节（GGN）分为A组,包括浸润前病变（2例）和微浸润腺癌（14例）,共计16例;B组为浸润性腺癌,共计14例。比较两组腺癌动、静脉期IC和Ki-67抗原表达的差异。结果：所有病例中,动、静脉期IC和Ki-67抗原表达呈负相关（r1=-0.749,P1=0.000;r2=-0.624,P2=0.000）;pGGN组动、静脉期IC和Ki-67抗原表达无相关性（P＞0.05）;mGGN组和实性结节组的动、静脉期IC和Ki-67抗原表达呈负相关（r1=-0.754、-0.617 ,P1＜0.05;r2=-6.09、-0.460,P2=＜0.05）。A组Ki-67抗原表达小于B组（P=0.001）,两组动、静脉IC的差异无统计学意义。结论：肺腺癌能谱CT相关参数和KI-67抗原表达有显著的负相关性,在评估肿瘤增殖能力方面具有潜在的价值,但在诊断GGN浸润程度的作用还有待进一步研究论证。     

MSCT薄层重建对表现为肺纯磨玻璃结节的肺腺癌浸润性的定量分析

目的 通过对表现为纯磨玻璃结节(pGGN)的浸润性肺腺癌组和非浸润性肺腺癌组的CT影像特征定量分析,提高两组之间的鉴别诊断.方法 选取并分析经手术及病理确诊的151例表现为单发pGGN患者,其中非浸润性腺癌组包括不典型腺瘤样增生(AAH)46例,原位癌(AIS)49例;浸润性腺癌组包括微浸润腺癌(MIA)31例,浸润性...     

肺局灶性磨玻璃密度结节的多层螺旋CT诊断

目的探讨肺局灶性磨玻璃密度结节(fGGO)的多层螺旋CT(MSCT)特征与病灶良恶性的相关性。资料与方法回顾性分析36例fGGO患者的影像学资料,包括8例炎症,18例肺泡癌,8例腺癌,2例非典型腺瘤样增生,评价病灶形态学特征及内部结构与良恶性的相关性。结果 8例炎症中7例呈斑片状;肺不典型腺瘤样增生(AAH)均为圆形或类圆形;细支气管肺泡癌(BAC)和腺癌主要呈圆形、不规则形及分叶征。11例BAC和腺癌边缘毛糙或伴毛刺征,16例边缘清晰、光整。15例胸膜凹陷征,均见于BAC和腺癌;16例胸膜增厚,3例见于炎症,13例见于BAC和腺癌。6例炎症和2例AAH为纯GGO,18例BAC和8例腺癌为混杂GGO。结论 fGGO的CT征象与病灶病理类型具有较高的相关性,对于提高其诊断准确率具有重要的临床价值。     

纯磨玻璃肺小腺癌内异常空气支气管征与病理亚型的相关性

目的探讨纯磨玻璃肺小腺癌(≤20mm)内异常空气支气管征与病理亚型的相关性。方法回顾性分析204例(216个结节)经手术病理证实为肺腺癌,均径在20mm以内的纯磨玻璃结节(pGGN)的影像、病理及临床资料。216个病灶中浸润前病变(PIL)130个,微浸润性腺癌(MIA)55个,浸润性腺癌(IAC)31个。将全部pGGN组(≤20mm)及亚厘米pGGN组(≤10mm)按有无异常空气支气管征各分为两组,采用χ~2检验或Fisher精确概率法分析两组间计量资料的差异,采用独立样本t检验分析两组间计数资料的差异。结果全部216个pGGN组(≤20mm)内,有异常空气支气管病灶23个,无异常空气支气管病灶193个,两组间在病理亚型和结节均径的差异有统计学意义(P0.05),密度差异无统计学意义(P0.05);在150个亚厘米pGGN组(≤10mm)内,有异常空气支气管病灶8个,无异常空气支气管病灶142个,两组间在病理亚型、密度、瘤肺界面的差异无统计学意义(P0.05),但两组的结节均径、边缘形态、胸膜凹陷征差异存在统计学意义(P0.05)。结论 pGGN肺小腺癌(≤20mm)内异常空气支气管征与病变的浸润性存在一定相关性;而亚厘米pGGN肺腺癌的浸润性则需要结合病灶大小、边缘形态等特征综合判断。     

多层螺旋CT在肺部局灶性磨玻璃密度结节诊断中的应用

目的探究多层螺旋CT在肺部局灶性磨玻璃密度结节诊断中的应用,并分析其应用价值。方法选取62例参与者都是肺部局灶性磨玻璃密度结节患者,先对患者肺部局灶性磨玻璃密度结节影像进行诊断分析,再对良性病变与恶性病变患者的病灶的病理特征、内部结构、邻近结构以及充气支气管征方面做对比分析。结果良性病变(炎症和AAH)和恶性病变(腺癌和BAC)的患者在病灶大小1cm方面,具有明显的差别(P0.05);恶性病变患者在近圆形、分叶状、不规则、光滑形、刺状、棘状突起、清晰、充气支气管征、Ⅱ型、Ⅲ型、胸膜凹陷和胸膜增厚等方面都要比良性病变患者人数多的多,具有明显的差别(P0.05)。结论 fGGO的MSCT征象和病灶的形态方面存在很高的相关性,在fGGO疾病的诊断方面提高精准度,有很高的应用价值。     

肺腺癌浸润前病变的CT诊断

【摘要】目的：探讨肺腺癌浸润前病变的CT表现。方法：回顾性分析2011年3月－2016年12月经手术病理证实的45例肺腺癌浸润前病变患者的临床和CT资料,其中不典型腺瘤样增生（AAH）10例、原位癌（AIS）35例,主要分析指标包括病灶分布、大小、密度、分叶征、毛刺征、空泡征、充气支气管征、肿瘤微血管成像征和胸膜凹陷征。结果：35例表现为纯磨玻璃密度结节、10例为部分实性成分磨玻璃密度结节;AAH组和AIS组中病灶直径分别为（10.15±3.72）和（11.73±4.58）mm,平均CT值分别为（－514±70.66）和（－477.2±168.08）HU,两组间差异均无统计学意义（P>0.05）。CT征象中以肿瘤微血管成像征最多见（出现率为68.9％）,其次是分叶征、空泡征（均为26.7％）,充气支气管征最少见（4.4％）;两组间各征象的差异均无统计学意义（P>0.05）。结论：肺腺癌浸润前病变的CT征象中肿瘤微血管成像征具有一定特异性,CT形态学征象并不能准确鉴别不典型腺瘤样增生和原位癌。     

磨玻璃密度小肺癌CT表现与病理类型相关性研究

目的：探讨磨玻璃密度（GCO）小肺癌的CT表现与病理类型相关性。方法：搜集43例（45个）表现为纯磨玻璃密度（pGGO）或混合磨玻璃密度（mGGO）的周围型小肺癌,根据GGO占整个病灶比例的不同分三型,分别与病理对照。并有12个小肺癌术前行中长期动态观察。结果：I型（GGO成分占91％-100％）11个,病理均为细支气管肺泡癌（BAC）;II型（GGO成分占51％。90％）21个,BAC11,BAC伴高分化腺癌4个,高分化腺癌4个,中分化腺癌2个;Ⅲ型（GGO成分占≤50％）13个,BAC3个,中分化腺癌5个,低分化腺癌3个,低分化鳞癌2个;通过三型间比较发现GGO所占比例越高,小肺癌的病理分化越好,GGO成分占≥50％时,病理多数为BAC（22／32）;同时对部分小肺癌术前中长期动态观察及术后随访,发现肿瘤生长缓慢、预后良好。结论：局限性GGO不仅是周围型肺癌的重要征象之一,而且通过半定量分析GGO所占比例的多少,能一定程度上预测其病理类型、分化程度、倍增时间及预后。     

肺小腺癌中原位腺癌半定量量化分级和病灶中磨玻璃密度含量的相关性研究

目的探讨肺小腺癌中原位腺癌半定量量化分级和病灶中磨玻璃密度含量的相关性。方法收集超高分辨率CT（UHRCT）发现并具病理诊断腺癌的最大径≤2cm的肺部孤立性结节fGGO104例,用计算机软件测量肿瘤内GGO成分的百分比,并对腺癌中的AIS成分半定量测定分为4级：Ⅰ级为AIS含量≥90％病灶面积,Ⅱ级为AIS含量占约50oA～89％病灶面积,Ⅲ级为AIS含量占约10％～49％病灶面积,Ⅳ级为AIS含量〈10oA病灶面积。对两者相关性进行分析。结果AISI级病灶32例,GGO平均含量85．69％;II级病灶30例,GGO平均含量68．75％;Ⅲ级病灶32例,GGO平均含量51．57％;Ⅳ级病灶10例,GGO平均含量37．46％;除3组和4组间差异无统计学意义外（P=0．078）,其他各组两两间GGO含量差异均有统计学意义（P〈O．05）。结论小腺癌中AIS含量与GGO含量正相关,但当AIs含量小于50％时,GG0含量与AIS含量没有明显相关性。     

甲型H1N1肺炎初诊CT表现

目的：探讨甲型H1N1肺炎特征性CT表现。方法：回顾性分析46例经咽拭子RT-PCR法检测确诊的甲型H1N1流感病毒肺炎的临床与CT资料,CT检查包括常规平扫、高分辨力CT（HRCT）及多平面重组（MPR）,4例行CT增强扫描。结果：46例H1N1肺炎累及双侧45例、累及单侧1例,40例侵犯3个肺叶及以上、6例侵犯2个肺叶及以下,均呈多灶性与弥漫性,32例沿支气管血管束分布、其中28例合并胸膜下分布,39例为GGO或GGO合并实变,20例可见马赛克征,15例见少量或中等量胸腔积液,仅1例合并肺栓塞。HRCT显示26例小叶间隔及小叶内间隔增厚、2例小叶中心模糊结节。结论：H1N1肺炎具有较特征性的CT表现,HRCT与MPR有助于其肺内病变的评价。     

Multidetector CT features of pulmonary focal ground-glass opacity: differences between benign and malignant

Objective

To evaluate different features between benign and malignant pulmonary focal ground-glass opacity (fGGO) on multidetector CT (MDCT).

Methods

82 pathologically or clinically confirmed fGGOs were retrospectively analysed with regard to demographic data, lesion size and location, attenuation value and MDCT features including shape, margin, interface, internal characteristics and adjacent structure. Differences between benign and malignant fGGOs were analysed using a χ² test, Fisher''s exact test or Mann–Whitney U-test. Morphological characteristics were analysed by binary logistic regression analysis to estimate the likelihood of malignancy.

Results

There were 21 benign and 61 malignant lesions. No statistical differences were found between benign and malignant fGGOs in terms of demographic data, size, location and attenuation value. The frequency of lobulation (p=0.000), spiculation (p=0.008), spine-like process (p=0.004), well-defined but coarse interface (p=0.000), bronchus cut-off (p=0.003), other air-containing space (p=0.000), pleural indentation (p=0.000) and vascular convergence (p=0.006) was significantly higher in malignant fGGOs than that in benign fGGOs. Binary logistic regression analysis showed that lobulation, interface and pleural indentation were important indicators for malignant diagnosis of fGGO, with the corresponding odds ratios of 8.122, 3.139 and 9.076, respectively. In addition, a well-defined but coarse interface was the most important indicator of malignancy among all interface types. With all three important indicators considered, the diagnostic sensitivity, specificity and accuracy were 93.4%, 66.7% and 86.6%, respectively.

Conclusion

An fGGO with lobulation, a well-defined but coarse interface and pleural indentation gives a greater than average likelihood of being malignant.With the availability of low-dose spiral CT scan of the lung, focal ground-glass opacity (fGGO) that was difficult to detect on conventional chest radiographs has increasingly been detected [1-3]. Ground-glass opacity (GGO) is defined as an area of a slight homogeneous increase in density, which does not obscure underlying bronchial structures or vascular margins on high-resolution CT (HRCT) [4]. Pathologically, GGO may be caused by partial airspace filling, interstitial thickening with inflammation, oedema, fibrosis, neoplastic proliferation, the normal respiratory condition or increased pulmonary capillary blood volume [5]. GGO can be classified as pure GGO (pGGO) or mixed GGO (mGGO) based on the presence of solid components. Although GGO is a common and non-specific finding of lung HRCT, and may occur in benign lung conditions such as organising pneumonia, focal fibrosis and haemorrhage [6-8], it has recently received considerable attention because it may indicate an early underlying lung cancer, which in most cases presents as bronchioloalveolar carcinoma (BAC) and adenocarcinoma with a predominant BAC component. It was reported in a study [9] that 17 of 28 pGGOs were BAC, 3 were adenocarcinoma and 8 were atypical adenomatous hyperplasia (AAH). Several other studies [10,11] have also indicated that mGGOs are more likely to be malignant, with the malignant rate of pGGO and mGGO being 18% and 63%, respectively [12]. The aim of the present study was to retrospectively compare the features of benign and malignant fGGOs on thin section multidetector CT (MDCT) images in an attempt to identify characteristics that would help the differential diagnosis of fGGOs.     

磨玻璃密度肺小腺癌病理亚型的Ultra-HRCT分析

目的:探讨直径≤2cm磨玻璃密度(GGO)肺腺癌的超高分辨率CT影像学表现与病理Noguchi分型的相关性.方法:回顾性分析56例表现为单纯磨玻璃密度(pGGO)或混合磨玻璃密度(mGGO)的周围型小肺癌的超高分辨率CT征象,分别与病理Noguchi分型对照.结果:病灶纯磨玻璃密度、分叶征、毛刺、胸膜凹陷、血管集束征/增粗和棘突征在各不同病理亚型中出现比率有显著差异,P值分别为0.001,0.022,0.002,0.022,0.032和0.012.而边缘、空泡、蜂房征在不同病理亚型无显著差异.结论:磨玻璃密度结节的部分形态学征象与病理Noguchi亚型有明显相关性,有助于预测病灶的恶性程度.     

Persistent pulmonary nodular ground-glass opacity at thin-section CT: histopathologic comparisons

PURPOSE: To retrospectively compare pure pulmonary ground-glass opacity (GGO) nodules observed on thin-section computed tomography (CT) images with histopathologic findings. MATERIALS AND METHODS: The institutional review board approved this study and waived informed consent. Histopathologic specimens were obtained from 53 GGO nodules in 49 patients. CT scans were assessed in terms of nodule size, shape, contour, internal characteristics, and the presence of a pleural tag. The findings obtained were compared with histopathologic results. Differences in thin-section CT findings according to histopathologic diagnoses were analyzed by using the Kruskal-Wallis test or Fisher exact test. RESULTS: Of 53 nodules in 49 patients (20 men, 29 women; mean age, 54 years; range, 29-78 years), 40 (75%) proved to be broncholoalveolar cell carcinoma (BAC) (n=36) or adenocarcinoma with predominant BAC component (n=4), three (6%) atypical adenomatous hyperplasia, and 10 (19%) nonspecific fibrosis or organizing pneumonia. No significant differences in morphologic findings on thin-section CT scans were found among the three diseases (all P>0.05). A polygonal shape (25%, 10 of 40 nodules) and a lobulated or spiculated margin (45%, 18 of 40) in BAC or adenocarcinoma with predominant BAC component were caused by interstitial fibrosis or infiltrative tumor growth. A polygonal shape and a lobulated or spiculated margin were observed in two (20%) and three (30%) of 10 nodules, respectively, in organizing pneumonia/fibrosis were caused by granulation tissue aligned in a linear manner in perilobular regions with or without interlobular septal thickening. CONCLUSION: About 75% of persistent pulmonary GGO nodules are attributed to BAC or adenocarcinoma with predominant BAC component, and at thin-section CT, these nodules do not manifest morphologic features that distinguish them from other GGO nodules with different histopathologic diagnoses.     

肺部局灶性磨玻璃影的CT诊断

目的探讨肺部良恶性局灶性磨玻璃影的CT表现,以期减少误诊和早期诊断周围型小肺癌。方法搜集资料完整的良性GGO结节43个(AAH6个,炎性37个)、恶性GGO结节77个(其中BAC62个、腺癌或混合性腺癌15个),对其CT表现作回顾分析。结果①大小:AAH≤1cm,6/6;炎性≥2cm,32/37;恶性1～2cm,44/77;②形态:球形,AAH6/6、炎性4/37、BAC43/32、腺癌10/15;③密度:纯GGO,AAH6/6、炎性33/37、BAC36/62;混杂GGO,炎性4/37、BAC26/62、腺癌15/15;④边缘:光滑,AAH6/6、炎性4/37、恶性73/77;⑤其它倾向肺癌征象(分叶、细毛刺、空泡、空气支气管征、血管集束、胸膜凹陷):AAH无;炎性极少;恶性常见;⑥.随访:10～45天抗炎后复查,无明显变化AAH6/6、炎性3/37、恶性70/77,缩小或吸收炎性34/37。结论①球形、边界清楚局灶性纯GGO影多为AAH或BAC,并且AAH多≤1cm;②混杂密度GGO,恶性可能大;③较大边界模糊斑片、不规则形纯GGO傾向炎性;④短期随访是重要鉴别手段。     

侵袭性肺曲霉菌病的MSCT表现

目的:探讨侵袭性肺曲霉菌病的MSCT表现。方法:回顾性分析19例经病理证实的侵袭性肺曲霉菌病的MSCT表现。结果:MSCT表现为小结节影(1～3cm)14例(73.6%,14/19),大结节或团块影(>3cm)6例(31.6%,6/19);肺段或亚段分布的实变影8例(42.1%,8/19),磨玻璃影3例(15.8%,3/19);6例(31.6%,6/19)合并CT晕圈征,5例(26.3%,5/19)合并空气新月征或空洞影,2例(10.5%,2/19)可见中心低密度征,5例(26.3%,5/19)合并胸水。结论:侵袭性肺曲霉菌病的主要征象是单发或多发的结节伴空洞形成及肺段或亚段的实变,而出现结节晕圈征和空气新月征时,则高度提示侵袭性肺曲霉菌病。     

甲型H1N1流感肺炎CT演变特点

目的:探讨甲型H1N1流感肺炎近中期CT演变特点。方法:回顾性分析35例临床确诊的甲型H1N1流感肺炎患者发热后1个月内86次CT资料,分析其肺部病变出现、进展及吸收时间和影像特点。结果:肺部病变发生时CT表现主要为肺部磨玻璃密度影或实变,胸腔积液等。CT复查表现分为3组:完全吸收组4例,表现为肺部磨玻璃密度影或实变在6～13d(平均11.25d)吸收;明显减轻组29例,表现为磨玻璃密度影及实变减轻或缩小,胸腔积液减少或消失;进展组2例,1例发热后第10天进展为ARDS,另1例合并真菌感染,复查后表现为实变及空洞扩大。2例远期复查中1例第73天仍浅淡磨玻璃密度影,1例第90d遗留少许磨玻璃密度影、小叶间隔增厚、小叶性结节及少许索条影。结论:甲型H1N1流感肺炎肺部病变多在发热后3天内出现,2周左右完全或部分吸收,部分病例中期复查可见间质性病变,危重症患者早中期CT即可见病变迅速进展。     

Progression of focal pure ground-glass opacity detected by low-dose helical computed tomography screening for lung cancer

OBJECTIVE: To clarify the progression of focal pure ground-glass opacity (pGGO) detected by low-dose helical computed tomography (CT) screening for lung cancer. METHODS: A total of 15,938 low-dose helical CT examinations were performed in 2052 participants in the screening project, and 1566 of them were judged to have yielded abnormal findings requiring further examination. Patients with peripheral nodules exhibiting pGGO at the time of the first thin-section CT examination and confirmed histologically by thin-section CT after follow-up of more than 6 months were enrolled in the current study. Progression was classified based on the follow-up thin-section CT findings. RESULTS: The progression of the 8 cases was classified into 3 types: increasing size (n = 5: bronchioloalveolar carcinoma [BAC]), decreasing size and the appearance of a solid component (n = 2: BAC, n = 1; adenocarcinoma with mixed subtype [Ad], n = 1), and stable size and increasing density (n = 1: BAC). In addition, the decreasing size group was further divided into 2 subtypes: a rapid-decreasing type (Ad: n = 1) and a slow-decreasing type (BAC: n = 1). The mean period between the first thin-section CT and surgery was 18 months (range: 7-38 months). All but one of the follow-up cases of lung cancer were noninvasive whereas the remaining GGO with a solid component was minimally invasive. CONCLUSIONS: The pGGOs of lung cancer nodules do not only increase in size or density, but may also decrease rapidly or slowly with the appearance of solid components. Close follow-up until the appearance of a solid component may be a valid option for the management of pGGO.