Objective  To discuss the value of CT quantitative parameters in prediction of the invasiveness of pulmonary mixed ground glass nodules (mGGNs).

  Methods  CT images of 164 patients with pulmonary ground-glass nodules (mGGNs), enrolled in Tianjin Medical University Cancer Institute and Hospital from January 2013 to September 2016, confirmed by surgical pathology were analyzed retrospectively. CT quantitative parameters including maximum diameter, largest diameter perpendicular to the maximum diameter, volume on both pulmonary window and mediastinal window, mean CT value and TDR (tumor shadow disappear rate) were evaluated between minimally invasive adenocarcinoma (MIA) and invasive adenocarcinoma (IAC) with ROC and Logistic regression analysis.

  Results  Logistic regression analysis showed that the maximum diameter of the pulmonary window (OR=3.080, 95% CI:1.135-8.355, P= 0.027) and the maximum diameter of the mediastinal window (OR=5.881, 95%CI:1.634-21.166, P=0.007) independently predicted the invasiveness of mGGNs; the corresponding values of area under the curve of the combination of two parameters were 0.855, with sensitivity of 77.61% and specificity of 86.67 %. The cut-off point to the corresponding value of the maximum diameter on pulmonary window and mediastinal window was 1.902cm and 1.273cm, respectively.

  Conclusions  CT quantitative parameters are helpful in predicting the invasiveness of mGGNs. The maximum diameters on both pulmonary window and mediastinal window are independent predictors.