Application Of Quantitative Parameters Of Spectral CT In The Evaluation Of Vascular Architecture In Solitary Pulmonary Nodule/Mass

Objective: To explore application of quantitative parameters of spectral CT in the evaluation of vascular architecture in solitary pulmonary nodule/mass.Method: A total of 39 patients(22 males,17 females)with pulmonary solitary nodules or masses who underwent spectral CT scan and were confirmed by postoperative pathology in the first Affiliated Hospital of Guangxi Medical University from November 2018 to January 2020 were collected.The age ranges from 35 to 74,with an average age of 57.28 years.All the selected patients have Scanned with GSI arterial and venous thoracic imaging of GE’s Revolution CT.The images post-processing were uploaded to GE AW4.7 workstation.GSI General software is used to measure the quantitative parameters of spectral CT,For example,Iodine concentration(IC)、Normalized iodine concentration(NIC)and Spectral HU curve in the arterial and venous phases,and calculate the slope of Spectral HU curve.Immunohistochemical markers such as CD31,SMA and ki-67 were used in the postoperative pathological specimens,and the parameters of vascular architecture parameters were calculated.According to pathology,39 cases of lesions were divided into non-malignant group(10 cases)and malignant group(29 cases).Corresponding statistical methods were used to compare the quantitative parameters of spectral CT and vascular architecture indexes of the two groups.The correlation between the parameters of vascular architecture and the quantitative parameters of spectral CT was analyzed.To investigate the correlation between ki-67 expression and iodine concentration related parameters of spectral CT in malignant group.According to the diameters,29 cases of lung cancer were divided into group A and group B,with diameter≤2cm in group A and diameter > 2cm in group B,including 11 cases in group A and 18 cases in group B.Independent sample T test was used to compare the quantitative parameters of energy spectral CT between the two groups.The malignant group was then divided into low-differentiation group and middle-differentiation group according to the degree of pathological differentiation.Independent sample T-test was used to compare the differences of vascular parameters between the two groups.The malignant group was divided into low-differentiation group and Middle-high differentiation group according to the degree of pathological differentiation.Independent sample T-test was used to compare the differences of vascular parameters between the two groups.Results: The slope of spectral curves、IC 、NIC of Arterial phase and venous phase in the malignant group and the non-malignant group were statistically significant(P < 0.05);Spectral CT parameters of lung cancer tissues with different diameters were different(P < 0.05).In the malignant group,there were no correlation between double-phase IC and NIC and the percentage of ki-67 positive cells and the expression level of ki-67(P >0.05).IC and NIC were correlated with microvascular parameters(CD31-MVD,SMA-MVD)at both arterial and venous phase(P < 0.05),But there is no correlation with MPI.The vascular parameters,SMA-MVD and MPI in the malignant group were lower than that in the non-malignant group,and the differences were significant(P <0.05).Conclusion: 1.spectral CT imaging technology can be used as an effective method for the differentiation of benign and malignant lung lesions.2.Parameters related to spectral CT iodine concentration can reflect the blood supply of malignant tumors.The larger the tumor diameter,the lower the blood supply.3.The IC and NIC in the arterial and venous phase were not correlated with the percentage of ki-67 positive cells and the expression level of ki-67,suggesting that the parameters related to iodine concentration may have limitations in evaluating the proliferation of tumor cells.4.The quantitative parameters IC and NIC of spectral CT can indirectly quantify the microangiogenic state in the lesion,and then observe the vascular architecture state of isolated pulmonary lesions dynamically and repeatedly.5.Vascular parameters can reflect the difference in vascular architecture in benign and malignant lesions.