The Value Of Pleural Tail Sign Predicting Visceral Pleural Invasion Of The Non-small Cell Lung Cancer With The Maximum Diameter Of Less Than 3cm

Objective: To investigate the predictive value of pleural tail sign on CT images for visceral pleural invasion of non-adjacent non–small cell lung cancer(NSCLC)with the maximum diameter of less than 3 cm.Materials and Methods: A retrospective analysis was performed on 157 non-adjacent NSCLC patients with the maximum diameter of less than 3cm.All patients were scanned with Philips brilliance 256 i CT to evaluate the imaging features of the pleural.According to the eighth edition of the TNM staging system as follows: PL0,no pleural involvement;PL1,tumor invasion of the elastic layer of the visceral pleural without reaching the visceral pleural surface;PL2,tumor invasion to the visceral pleural surface;and PL3,tumor invasion of the parietal pleura or chest wall.Pleural tail sign is defined as one or more linear cords extending from the surface of the nodule to the surface of the pleural due to thickening of the lobular septum.According to the relationship between tumors and pleural on CT images,pleural tail signs were classified into three types(type 1,one or more linear pleural tail signs;type 2,one or more linear pleural tail signs with soft tissue component at the pleural end;and type 3,one or more soft tissue cord-like pleural tail signs)and prioritized into type 3,2,and 1 when more than one types were present.Diagnostic accuracy,sensitivity,specificity,positive predictive value(PPV),negative predictive value(NPV),and positive likelihood ratio(LR)were calculated.Hematoxylin eosin staining,Victoria blue staining and immunohistochemical staining were used to evaluate the stage of pleural invasion at the level of histopathology,so that the interpretation results were more accurate.Results:In this study,of 157 cases,the presence of pleural invasion was detected in 37 cases and the absence of pleural invasion was confirmed in the remaining 120 cases.1.pathological results: 61 cases of pleura invasion,86 cases of no pleura invasion and 10 cases of difficult to read were identified by conventional HE stained.Victoria blue staining and immunohistochemical staining were used to verify the results of HE staining: among 61 cases of pleural invasion by HE staining,30 cases were confirmed as invasion,31 cases were not invasion;among 86 cases of non-invasion,81 cases were confirmed as non-invasion,5 cases were invasion;among 10 cases of difficult to interpret,2 cases were confirmed as invasion,8 cases were not invasion.Finally,37 cases of pleural invasion were identified(PL1 16 cases,PL2 21 cases),120 cases had no pleural invasion,and no patients invaded parietal pleura,chest wall,or mediastinum(PL3).The histopathological level reference standard of pleura invasion was determined as the imaging reference standard.2.the result of clinical data: There was no statistically significant difference in terms of the age,location,gender,histological type and N stage between the pleural invasion group and the non-invasion group.The maximum diameter of tumor was statistically significant between the visceral pleural invasion group and the non-invasion group(P <0.05).The maximum diameter of tumor had good consistency among observers and ICC was 0.97.3.the result of Image data 3.1 CT image measurement results: the minimum distance from the lesion to the pleura(DLP)on transverse image was different statistically significantly between the visceral pleural invasion group and the non-invasion group(P <0.05).DLP had good consistency among observers and ICC was 0.98.3.2 The results of predicting the invasion of visceral pleural by various pleura tail signs: according to the above pathological results,the classification of the relationship between tumor and pleura were statistically significant in the visceral pleural invasion group and the non-invasion group(P <0.05).There was a good consistency between the observers(k = 0.85).The classification of the relationship between tumors and pleura: there were 127 cases(80.89%)with pleura tail sign,30 cases(19.11%)without pleura tail sign,89 cases(56.69%)with type I,18 cases(11.46%)with type II and 20 cases(12.74%)with type III.In patients with no pleural tail sign,no visceral pleural invasion was confirmed by pathology.The positive rate of visceral pleural invasion in type ? is higher than that in type ? and type ? for NSCLC with the following results: accuracy,77.17%;sensitivity,37.84%;specificity,93.33%;PPV,70.00%;NPV,78.50%;and positive LR,5.67.The results of the presence of type II pleural tail sign were as follows: accuracy,66.14%;sensitivity,16.22%;specificity,86.67%;PPV,33.33%;NPV,71.56%;and positive LR,1.22.The presence of type 1 pleural tail sign was deemed weak evidence to rule out visceral pleural invasion,and the results were as follows: accuracy,27.56%;sensitivity,45.95%;specificity,20.00%;PPV,19.10%;NPV,47.37%;and positive LR,0.57.The presence of pleural tail sign overall was shown to minimally increase the likelihood of visceral pleural invasion,and the results were as follows: accuracy,42.68%;sensitivity,100%;specificity,25.00%;PPV,29.13%;NPV,100%;and positive LR,1.33.3.3 Conclusion: Pleural tail sign on CT images is valuable for predicting visceral pleural invasion in non-small cell lung cancer.No pleura tail sign on CT is suggestive of no invasion of visceral pleural.The type ? pleural tail sign is highly predictive of the invasion of visceral pleural for non-adjacent NSCLC with maximum diameter less than or equal to 3cm.