Preliminary Study For CT Spectral Imaging In The Diagnosis Of Lung Benign And Malignancy Mass

ObjectiveTo investigate the preliminary application of spectral CT on the discrimination of benign and malignant lung mass by spectral CT scan and multi-parameter quantitative measurement such as Iodine concentration, water concentration, spectrum energy curve and CT value at40keV.MethodsEighty-one patients who were found lung mass by X-ray or CT plain scan at first time were scanned in spectral mode by using spectral CT, the non-ionic contrast medical lohexol (300mg I/ml) at the dose of1.5ml/kg was injected with power injector at a rate of3ml per second through median cubital vein,collimation:40mm, thickness:5.0mm,inter-val:5.0mm, auto-mA,voltage:140/80kv, Iodine concentration, water conce-ntration, spectrum energy curve and CT value at40keV in the region of interest of the mass were measured with spectral post-processing software.Reform the5.0mm thicken conventional polychromatic images into0.625mm thicken monochromatic ones and send them to AW4.4work-station. All the data was processed by GSI Viewer software. The lump substance composition was selected as region of interest,avoiding the necrotic tissue, cavity, calcification and blood vessels to measure iodine concentration, water concentration and40keV corresponding CT value, and calculate the corresponding spectral curve slope:CT (40keV)-CT (100keV)/(40keV-100keV), all energy spectrum curves were standardized by water energy spectrum curve.70eligible patients were divided into pneumonia group and tumor group. SPSS17.0software with ANOVA method was used for statistic analysis in the two groups and P<0.05was considered statistically significant difference.ResultsIn81cases of patients,5cases was not obtain pathologic findings,2cases failed to measure with contrast material artifacts affect,4cases with obvious signs and benign lesions confirmed by pathologic findings (bronchial cyst, myxoma, border was clear with internal uniform density, there was no obvious enhancement in the lesion, the spectral curve and water spectrum curve of approximate parallel).Included in the statistical analysis of70cases, male51cases, and female19cases, mean age was62years old (minimum age48, the biggest age82years),70eligible patients were divided into pneumonia group and tumor group, in which inflammation group including pneumonia group (acute and chronic inflammation, activity, including machine pneumonia, tuberculosis, inflammatory pseudotumor and suppurative pneumonia)22cases and tumor group (non-small cell lung cancer)48patients.The iodine concentration in pneumonia group and tumor group were (1.47±0.17),(0.77±0.19)(F=203.97, P<0.05) respectively; The spectrum energy curve in pneumonia group and tumor group were (1.65±0.27),(0.88±0.22)(F=161.59, P<0.05) respectively; The CT value at40keV in pneumonia group and tumor group were (139±16.25),(83.29±17.44)(F=160.45.P<0.05),which indicated difference existed in iodine concen-tration, spectrum energy curve and CT value at40keV between pneu-monia group and tumor group, while water concentration were found no difference between them (F=0.19,P>0.05),the water concentration in pneumonia group and tumor group were (1021.56±11.68),(1022.62±8.56) respectively.ConclusionSpectral CT with multi-parameter quantitative measurement such as Iodine concentration, water concentration, spectrum energy curve and CT value at40keV have important value in the discrimination of benign and malignant lung mass by providing qualitative and quantitative infor-mations.