Value of dynamic contrast-enhanced MRI parameters of Extended Tofts and Exchange model in the differential diagnosis of hepatocellular carcinoma and hepatic metastases / 中华放射学杂志

ABSTRACT

Objective To analyze the value of dynamic contrast-enhanced MRI(DCE-MRI) parameters of Extended Tofts and Exchange model in the differential diagnosis of hepatocellular carcinoma (HCC) and hepatic metastases of colorectal cancer. Methods A retrospective analysis of 40 pathologically confirmed cases was conducted , including 25 cases of HCC and 15 cases of hepatic metastases of colorectal cancer,all patients underwent DCE-MRI. Applying liver double blood supplement model , and respectively using Extended Tofts two-compartment model and Exchange model liver microvascular permeability parameters [volume transfer constant of the contrast agent(Ktrans), efflux rate from extracellular extravascular space to plasma(Kep), extravascular extracellular volume fraction(Ve)and blood plasma space volume fraction (Vp)] and the perfusion parameter hepatic arterial perfusion index(HPI) in the lesion parenchyma of HCC and metastases were calculated. We used t test to compare the differences of the parameters measured from the two types of tumors , statistically significant parameters between HCC and metastases were screened which compared with the gold standard of pathological findings in order to draw the ROC curves to evaluate the diagnostic efficacy of different model parameters, using χ2 test compared the diagnostic accuracy of optimal parameters between the two models. Results By using Extended Tofts and Exchange model , Ktrans value of HCC were (0.661 ± 0.402)/min and (0.604 ± 0.316)/min respectively, Ktrans value of hepatic metastases were (0.196±0.175)/min and (0.179±0.135)/min respectively;Vp value of HCC were (0.334±0.217) and (0.294± 0.098), Vp value of hepatic metastases were (0.089 ± 0.015) and (0.089 ± 0.022),respectively; HPI value of HCC were (0.680±0.281) and (0.769±0.245) , HPI value of hepatic metastases were (0.326±0.216), (0.373± 0.298), respectively. There were significant differences between HCC and hepatic metastases in Ktrans, Vp and HPI values in both models(P0.05).Drawn ROC curves of Ktrans, Vp, HPI , the Ktrans value (area under the curve of 0.869) among Extended Tofts model parameters was selected as optimal parameter to identify HCC and hepatic metastases; the HPI value (area under the curve of 0.845) among Exchange model parameters was selected as optimal parameter to differentiate these two types of tumors.The diagnostic accordance rate of Extended Tofts model and Exchange model were 80.0%(32/40), 82.5%(33/40), respectively ; There was no significant difference between them(χ2=0.082,P=0.775). Conclusions Parameters including Ktrans, Vp, HPI of the Extended Tofts model and Exchange model in DCE-MRI perfusion can be used to identify HCC and hepatic metastases of colorectal cancer. Among these parameters, Ktrans of Extended Tofts model and HPI of Exchange model have higher diagnostic value in differentiating HCC and hepatic metastases of colorectal cancer.