Extracellular Volume Fraction Based On Contrast-enhanced CT Images Predicts Hepatic Metastasis And Lymphatic Metastasis From Colon Carcioma

Purpose:To assess whether extracellular volume(ECV)fraction with equilibrium contrast-enhanced multidetector computed tomography(MDCT)predicts hepatic metastasis and lymphatic metastasis from colon carcinoma.Methods:From February 2017 to March 2019,90 patients(65 males,25 females;median age 63 years;range 30-85 years)with histologically confirmed colonic adenocarcinoma underwent equilibrium contrast-enhanced multidetector computed tomography(MDCT),and 58 patients underwent surgery.Tumour contrast enhancement(CE)and ECV fraction were calculated by using region-of-interest measurement within the colonic adenocarcinoma and aorta on unenhanced and equilibrium phase-enhanced CT.Two radiologists also determined the peak enhancement phase by independently reviewing the CT images and they measured the CT attenuation value of the colonic lesion for each phase.We compared the parameters including CE,ECV fraction,CT attenuation value and the peak enhancement phase by using analysis of rank sum test for comparison of two independent samples or chi-square test.We calculated diagnostic performance of ECV fraction and CE for diagnosing hepatic metastasis and lymphatic metastasis of coloncarcinoma by receiver operating characteristic(ROC)analysis and decision curveanalysis(DCA)analysis.Results:The ECV fraction and CE of hepatic metastasis were significantly higher than those of negative hepatic metastasis(34.0% vs 28.1%,P=0.00<0.05;42.81 vs 37.65,P=0.017<0.05).In the ROC analysis,the area under curve(AUC)of hepatic metastasis predicted by ECV fraction and CE were 0.807 and 0.654,respectively.When the optimal cut-off was set at31.2% and 32.75 HU,the sensitivity,specificity in predicting hepatic metastasis were 74.2%,78.1% with ECV fraction and 93.5%,27.1% with CE.The ECV fraction and CE of lymphatic metastasis were significantly higher than those of negative lymphatic metastasis(33.4% vs 28.3%,P=0.001<0.05;42.74 vs 37.72,P=0.013<0.05).In the ROC analysis,the area under curve(AUC)of lymphatic metastasis predicted by ECV fraction and CE were 0.768 and 0.691,respectively.When the optimal cut-off was set at 27.5% and 36.50 HU,the sensitivity,specificity in predicting lymphatic metastasis were 92.0%,48.5% with ECV fraction and 88.0%,51.5% with CE.In decision curveanalysis analysis,ECV fraction models also had a larger net benefit than CE.The peak enhancement and the CT values were no signifificantly difffferent(p>0.05).Conclusion:The ECV fraction with equilibrium contrast-enhanced MDCT could be a useful imaging biomarker for predicting hepatic metastasis and lymphatic metastasis from colon carcinoma.