Quantitative Analysis Of Spectral CT Imaging On Hypervascular Hepatic Metastasis And Hepatocellular Carcinoma

Objective:To evaluate the value of the spectral CT quantitative analysis in the differential diagnosis of hypervascular hepatic metastasis(HVHM)and hepatocellular carcinoma(HCC)by analyzing the quantitative multi-parameters acquired from the spectral CT contrast-enhanced scan.Materials and Methods:57 patients with hepatic malignant tumors underwent spectral CT contrast-enhanced scan including HVHM group(n=26)and HCC group(n=31)in Qianfoshan Hospital Affiliated to Shandong University.All the patients underwent gemstone spectral imaging(GSI)scan including plain scan and arterial,portal venous,delayed phase enhancement.The arterial and portal venous phase enhancement scanning were scaned in GSI mode,the plain scan and delayed phase enhancement scanning were scaned in routine mode.The raw data of arterial and portal venous phase conventional polychromatic images of thickness were reconstructed into 0.625 mm thicken monochromatic images and sent them to GE AW4.4work-station.All data were analyzed by GSI Viewer software.The region of interest(ROI)on the tumors were placed on the edge regions of the lesion with the most significant enhancement,the ROI on the normal liver parenchyma and abdominal aorta were placed at the same transverse slice.Measure the iodine concentration,water concentration of the lesion and the iodine concentration of normal liver parenchyma and abdominal aorta.Then calculated the normalized iodine concentration(NIC),the lesion-normal parenchyma iodine concentration ratio(LNR),iodine concentration difference(ICD)between the arterial phase and the portal venous phase.Obtained the spectral curve of the lesion and calculated the slope of the spectral curve.Independent samples t test and receiver operating characteristic curves(ROC)were applied to analyze the quantitative parameters.Results:Differences of the NIC,LNR and the slope of spectral curve were not statistically significant(P>0.05)between HVHM group and HCC group during arterial phase.Differences of the NIC,LNR and the slope of spectral curve were statistically significant(P<0.05)between HVHM group and HCC group during portal venous phase.Differences of water concentration in arterial and portal venous phase and ICD between HVHM group and HCC group were not statistically significant(P>0.05).The slope of spectral curve in the portal venous phase had the highest diagnostic efficiency in differentiating HVHM group from HCC group,the sensitivity and specificity were 92.3%,90.3% respectively.Conclusions:Differences of the NIC,LNR and the slope of spectral curve were not statistically significant(P>0.05)between HVHM group and HCC group during arterial phase.However the NIC,LNR and the slope of spectral curve in the HVHM group were statistically higher than HCC group during portal venous phase,and the slope of spectral curve had the highest diagnostic efficiency in the differential diagnosis.HVHM and HCC have different spectral characteristic parameters and spectral curves.Spectral CT imaging with the quantitative analysis provides a new multi-parameter imaging method for differentiating HVHM and HCC.