¹⁸F-FDG PET-CT Characteristics In Differenting Diagnosis Of Lung Adenocarcinoma With Pure Ground Glass Density

Objective Analysis of the metabolic characteristics and CT morphological features of¹⁸F-FDG PET in the pre-invasive lesions?AAH-AIS?,microinvasive adenocarcinoma?MIA?,and invasive adenocarcinoma?IAC?of purely ground glass-density pulmonary nodules?pGGN?,propose differential diagnosis points.Materials and Methods Retrospective analysis of imaging data from ¹⁸F-FDG PET-CT in our hospital from October 2010 to August 2018,all cases were confirmed by surgical pathology.A total of 173 patients,a total of 189 lesions were included in the study,26cases of preinvasive lesions?including AIS and AAH?,27 lesions,40 cases of MIA,49lesions,107 cases of IAC,113 lesions.According to the pathological diagnosis results,the patients were divided into three groups:group A was compared with non-invasive cancer?including MIA,AIS and AAH?,group B was compared with IAC and MIA,group C was MIA and pre-invasive lesions?including AIS and AAH?comparative analysis.Analysis of clinical data,size,density,morphology and metabolic characteristics.Univariate logistic regression was performed on the data between groups,and multivariate logistic regression was performed on the statistically significant differences.P<0.05 was meaningful.A receiver working curve?ROC curve?was constructed for Dmax,density,SUVmax,and T/N values to calculate the optimal cut off value.Results Group A:Dmax,CT value,SUVmax,and T/N values of non-invasive cancer group in IAC group were?19.14±5.47?mm and?11.41±5.20?mm,?-435.76±134.13?HU and?-578.72±142.37?HU,1.03±0.56 and 0.64±0.31,2.24±1.18 and 1.41±0.58,AUC were 0.87,0.81,0.73,0.79,the critical values were 12.60mm,-520.75HU,0.76,1.41,the sensitivity were 0.90.0.78,0.68,0.80,the specificities were 0.72,0.72,0.78,0.65,and the accuracy were 0.83,0.88,0.67,0.78.The IAC group had higher Dmax,higher density and higher metabolism than the non-invasive cancer group.There were a total of 79 lung tumors in the IAC group and 16 in the non-invasive cancer group.The incidence of the IAC group was higher than that of the non-invasive cancer group.There were 28 vascular signs in the IAC group and 6 in the non-invasive cancer group.The proportions were higher than that of the non-invasive cancer group.Dmax,maximum volume,CT value,clear junction of the tumor,vascular sign were independent factors influencing the invasive and non-invasive cancer groups,and the OR values were 1.78,0.99,1.00,0.02,and 255.13,respectively.Group B:Dmax,CT value,SUVmax,and T/N values of IAC group and MIA group were?19.14±5.47?mm and?11.34±4.97?mm,?-435.76±134.13?HU and?-572.68±142.61?HU,1.03±0.56 and 0.63±0.32,2.24±1.18 and 1.37±0.48,AUC were 0.87,0.80,0.74,0.80,the critical points were 11.74mm,-558.83HU,0.85,1.41,the sensitivity were 0.89.0.89,0.59,0.80,the specificity were 0.74,0.61,0.84,0.69,the accuracy were 0.95,0.81,0.59,0.80.The IAC group was larger than the MIA group,with high density and high metabolism.There were 28 vascular signs in the IAC group and 4in the MIA group.The proportion of IAC group was higher than that in the MIA group.Dmax,maximum volume,and vascular signs were independent influencing factors in the IAC and MIA groups,with OR values of 1.93,0.98,and 969.73.Group C:Dmax,CT,SUVmax,and T/N values of the MIA group and the pre-invasive lesion group were?11.34±4.97?mm and?11.54±5.64?mm,?-572.68±142.61?HU and?-589.67±143.98?HU,0.63±0.32 and 0.65±0.29,1.37±0.48 and 1.48±0.74.There were no significant difference in Dmax,CT value and metabolism between MIA group and pre-invasion group.There were 10 vacuoles in the MIA group and 9 in the pre-invasive lesion group.The incidence of the pre-invasive lesion group was higher than that in the MIA group.There were 31lobular signs in the MIA group and 9 in the pre-invasive lesion group.The MIA group The incidence was significantly higher than the pre-invasive lesions.The lobulated,vacuolated,maximum cross-sectional area and maximum volume of the lesions were statistically significant,with OR values of 12.46,0.16,0.92,and 1.00.Conclusion The clearer the interface of the tumor and the occurrence of vascular signs suggest that the lesion was likely to be IAC.The lobulation sign indicates that the lesion begins to appear invasive,which was likely to be a lesion of MIA and IAC.The results of ROC curve analysis indicated that Dmax?11.74mm,density?-558.83HU,and T/N value?1.41 were the best critical values for differential diagnosis of IAC and MIA.