DCE-MRI of hepatocellular carcinoma: perfusion quantification with Tofts model versus shutter-speed model—initial experience

Objective: To quantify hepatocellular carcinoma (HCC) perfusion and flow with the fast exchange regime-allowed Shutter-Speed model (SSM) compared to the Tofts model (TM). Materials and methods: In this prospective study, 25 patients with HCC underwent DCE-MRI. ROIs were placed in liver parenchyma, portal vein, aorta and HCC lesions. Signal intensities were analyzed employing dual-input TM and SSM models. ART (arterial fraction), K^trans (contrast agent transfer rate constant from plasma to extravascular extracellular space), v_e (extravascular extracellular volume fraction), k_ep (contrast agent intravasation rate constant), and τ_i (mean intracellular water molecule lifetime) were compared between liver parenchyma and HCC, and ART, K^trans, v_e and k_ep were compared between models using Wilcoxon tests and limits of agreement. Test–retest reproducibility was assessed in 10 patients. Results: ART and v_e obtained with TM; ART, v_e, k_e and τ_i obtained with SSM were significantly different between liver parenchyma and HCC (p < 0.04). Parameters showed variable reproducibility (CV range 14.7–66.5 % for both models). Liver K^trans and v_e; HCC v_e and k_ep were significantly different when estimated with the two models (p < 0.03). Conclusion: Our results show differences when computed between the TM and the SSM. However, these differences are smaller than parameter reproducibilities and may be of limited clinical significance.