| Part I Pulmonary ground glass nodules:The correlations between HRCT features and 2015 WHO pathological classification of lung adenocarcinomaOBJECTIVE To evaluate the correlations between high resolution CT (HRCT) findings and 2015 WHO pathological classification of pulmonary ground glass nodules (GGNs) and to evaluate the accuracy of HRCT for GGN pathological subtypes and infiltrated status.METHODS From October 2010 to December 2015,316 GGNs (260 pure ground glass nodules and 47 part solid nodules with solid portion< 5mm in largest diameter) pathologically confirmed in 287 patients were included in this study. All nodules were divided into two groups according to the pathological result:pre-invasive/minimally invasive adenocarcinoma and invasive adenocarcinoma. The patient gender, age, nodular location, size (including diameter and volume), mean CT value, relative CT value, mass and imaging features (including lobulated shape, spiculated sign, marginal limit sign, vocule sign or air bronchogram, pleural tag or pleural indentation sign) were assessed. Pearson x2 test, one-way ANOVA, Mann-Whitney U were used to analyze the variables. The variables that exhibited statistically significant differences were included in a binary logistic regression analysis. Receiver operating characteristic (ROC) analyses were conducted for the variables that exhibited statistically significant differences in the binary logistic regression, drew ROC curves, then the optimal cut-off values were confirmed.RESULTS Of 316 pulmonary GGNs, all the 9 thin-walled cavitary GGNs were histologically confirmed invasive adenocarcinoma (IAC), the other 307 GGNs were divided into two groups according to the pathological result:112 AAH/AIS/MIA nodules and 195 IAC nodules (100 lepidic adenocarcinomas,76 acinar adenocarcinomas and 19 papillary adenocarcinomas). There were no significant differences among patient gender, lesion location, and nodular marginal limit sign between the both groups (P> 0.05). Patient age (52.8±9.5 VS 56.4±9.5), imaging features (including lobulated shape, spiculated sign, vocule sign or air bronchogram and pleural tag or pleural indentation), nodular size, mean attenuation value, relative CT value, volume and mass were significantly different between the both groups (P<0.05). The results of binary logistic regression and ROC analysis showed that nodular mass was an independent factor in differentiating AAH/AIS/MIA from IAC [P=0.000,Odds Ratio(OR)=840.864], The sensitivity and specificity of GGN mass (cutoff,0.28g) were 68.7% and 92.9%. In IAC histopathologic subtypes analysis, vocule sign or air bronchogram was significantly different between lepidic adenocarcinoma and acinar adenocarcinoma (p=0.013). The mean attenuation value of papillary adenocarcinoma was higher than that of lepidic adenocarcinomas and acinar adenocarcinoma (p< 0.001, 0.047), and the mean attenuation value of acinar adenocarcinoma was higher than that of lepidic adenocarcinoma (p=0.001). There was significantly different between acinar adenocarcinoma and papillary adenocarcinoma in terms of the relative CT value (p=0.045).CONCLUSION GGN mass can be used as a reliable reference in differentiating between IAC and AAH/AIS/MIA. GGN morphological characteristics including lobulated shape, spiculated sign, vocule sign or air bronchogram, pleural tag or pleural indentation sign are more common in the IAC. The nodule size, CT value and volume of GGNs are higher than that of AAH/AIS/MIA. In IAC pathological subtypes, vocule sign or air bronchogram is more common in acinar adenocarcinoma, and the CT value is the highest in papillary adenocarcinoma, followed by the acinar adenocarcinoma and the lepidic predominant adenocarcinoma. AAH of more than 10mm in size and AIS of more than 15mm in size are rare. Thin-walled cavitary GGN have more diagnostic value for invasive adenocarcinoma. Interstitial infiltration can appear as nonsolid on HRCT, and the solid composition in GGN is not necessarily the infiltration.Part II The correlation between imaging features of adenocarcinoma ground-glass nodules with EGFR mutationsOBJECTIVE Our study was retrospectively identify quantitative high-resolution computed tomography (HRCT) features that correlate with epidermal growth factor receptor(EGFR)mutation in surgically resected lung adenocarcinomas with pure ground glass nodule (pGGN) and GGN with solid portion less than 5 mm.METHODS From April 23rd,2012 to October 30th,2015, the HRCT appearances were retrospectively analyzed in 79 resected GGNs in Cancer Hospital/Institute,Chinese Academy of Medical Sciences which were confirmed lung adenocarcinomas in pathology. EGFR mutations were detected by quantitative PCR. All the patients were divided into EGFR mutation group and wild type group. The patient gender, age, nodular size (including diameter and volume), relative CT value, mass and imaging features (including lobulated shape, spiculated sign, vocule sign or air bronchogram, pleural tag or pleural indentation) were recorded in each group respectively. The correlation between HRCT features of GGN and EGFR mutations was analyzed. The statistical analysis was made.RESULTS Of all 79 patients, EGFR mutations were found in 41 patients (51.9%) and EGFR wild types were found in 38 patients(48.1%). There were no significant differences among patient gender, age, lesion location, relative CT value, and imaging features (including lobulated shape, spiculated sign, vocule sign or air bronchogram) between EGFR mutation and wild type. The pleural tags or pleural indentations were more often seen in EGFR mutation group than in wild type group (p=0.037). There were significant differences among GGN size, volume and mass between EGFR mutation group and wild group (p=0.000,0.002,0.001). For predicting EGFR mutation, the area under the curve (AUC) was 0.720,0.752 and 0.801 respectively in GGN size, volume and mass. The cutoff value was 10.45mm,540.6mm3 and 0.255 g, respectively.CONCLUSION The HRCT features may be useful in predicting EGFR gene mutation for pGGN and GGN with solid portion less than 5 mm. |
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