Application Of Gemstone Spectral CT In Differentiation Of Solitary Pulmonary Nodules Or Masses

Objective:To explore the value of gemstone Spectral CT in differentiation of lung cancer,pneumonia and pulmonary tuberculosis.Methods:A total of 78 patients with lung nodules or mass received dual phase(arterial phase,AP;venous phase,VP)contrast enhanced chest CT scan on a dual energy spectral CT(Discovery CT750 HD,GE healthcare).The patients were divided into lung cancer group(38 cas es),pneumonia group(20 cases)and pulmonary tuberculosis group(20 cases)accor ding to pathology and follow-up results after treatment.The CT value of monochro matic at the energy levels ranging from 40 to 100 keV,iodine concentration(IC),wa ter concentration(WC)and slopes of spectral attenuation curves in the peripheral zo ne of lesions were measured,and iodine concentrations in the central zone of pneu monia and lung cancer were measured.Then the iodine concentration and water con centration of thoracic aorta or subclavian artery at the same level were measured,a nd the normalized iodine concentration(NIC)and standard water concentration(N WC)were calculated by IC of lesions relative to that of aorta.The ANOVA and Kr uskal-Wallis H test were used to compare parameters among 3 groups.Independent student T test was used to compare parameters between two groups.Receiver operat ing characteristic(ROC)curve was performed to access the value of differential dia gnosis.Results:The CT value of monochromatic(40-100keV),IC,NIC and slope rate of spectral curve in the three groups had statistically significant differences in both phases(all P<0.05).WC?NWC show no statistically significant difference(P>0.05).Multiple comparison between lung cancer and pulmonary tuberculosis,pneumonia an d pulmonary tuberculosis were statistically significant(P<0.05),but there is no statis tically significant between lung cancer and pneumonia(P>0.05).IC,NIC and dNIC in central zone of pneumonia and lung cancer has statistically significant differences in both phases(all P<0.05).When NICper-VP=0.325,0.297,the sensitivity of diagnosing pneumonia and pulmonary tuberculosis,lung cancer and tuberculosis were respectiv ely 95%,97%,and the specificity of them were 85%,75% respectively.And whenNICcen-AP=0.062,the sensitivity and specificity of diagnosing lung cancer and pneum onia is 95%,75% respectively.Conclusion:The quantitative analysis of multiple para meters from spectral CT imaging has great value in the differentiation of lung can cer,pneumonia and pulmonary tuberculosis.