Background: Three-dimensional (3D) whole-liver perfusion magnetic resonance (MR) imaging with parallel imaging, a novel imaging method to characterize tumor vascularization in vivo, has recently been applied to comprehensively image perfusion changes in large tumors. Coupled with new perfusion software, this technique enables motion correction, registration, and evaluation of perfusion MR parameters. The purpose of this study was to assess the feasibility of 3D whole-liver perfusion MR, for imaging hepatocellular carcinoma (HCC) and colorectal hepatic metastases (CRHM).
Methods: 26 patients with hepatic tumors (10 HCC; 16 CRHM) were subjected to 3D whole-liver perfusion MR with a temporal resolution of 3.7 seconds. The following estimated perfusion parameters were measured: the volume transfer constant K(trans) (min(-1)); the volume (V(e)) of extravascular extracellular space (EES) per volume unit of tissue; and the flux rate constant between EES and plasma K(ep) (min(-1)). Statistical analysis was conducted to investigate inter-observer characteristics and significance of the measured parameters.
Results: Inter-observer agreement analysis (95% limits of agreement) yielded a mean difference of -0.0048 min(-1) (-0.0598 ~ 0.0502) for K(trans), -0.0630 ml (-0.5405 ~ 0.4145) for V(e), and -0.0031 min(-1) (-0.0771 ~ 0.0709) for K(ep) respectively. When comparing images from patients with HCC vs. CRHM, significant differences were seen for the mean K(trans) (p = 0.017), but not for V(e) (p = 0.117) or K(ep) (p = 0.595).
Conclusion: Herein we show that 3D whole-liver MR perfusion imaging with semi-automatic data analysis is feasible and enables the reliable quantitative evaluation of the perfusion parameters for HCCs and CRHMs.