Diffusion-Related MRI Parameters for Assessing Early Treatment Response of Liver Metastases to Cytotoxic Therapy in Colorectal Cancer

Abstract

OBJECTIVE. The objective of our study was to evaluate early therapeutic response after cytotoxic chemotherapy in patients with liver metastasis from colorectal cancer (CRC) using intravoxel incoherent motion (IVIM) DWI and dynamic contrast-enhanced MRI (DCE-MRI). SUBJECTS AND METHODS. Nineteen patients with liver metastasis from CRC underwent DCE-MRI and IVIM DWI at baseline and after the first cycle of chemotherapy. IVIM DWI parameters including the apparent diffusion coefficient (ADC), true diffusion coefficient (D), pseudodiffusion coefficient (D*), and perfusion fraction (f) and DCE-MRI perfusion parameters including the volume transfer constant (K-trans), reverse volume transfer constant (K-ep), extravascular extracellular volume fraction (V-e), and initial area under the concentration curve in 60 seconds (iAUC) were calculated. The response evaluation was based on Response Evaluation Criteria in Solid Tumors version 1.1. RESULTS. There were eight responding and 11 nonresponding patients. ADC (baseline value vs value after first cycle of chemotherapy [mean +/- SD]: 1191.9 +/- 232.2 vs 1263.5 +/- 266.4 x 10(-3) mm(2)/s; p = 0.012), D (1085.9 +/- 232.9 vs 1173.5 +/- 248.9 x 10(-3) mm(2)/s; p = 0.012), and f (173.7% +/- 39.8% vs 133.5% +/- 28.3%; p = 0.017) showed a significant change after the first cycle of chemotherapy in the response group, whereas ADC and D showed no significant change in the nonresponse group. In addition, DCE-MRI perfusion parameters showed no significant changes. A correlation was found between each of perfusion-related IVIM parameters and the DCE-MRI parameters before chemotherapy (r = 1.33, p > 0.05). CONCLUSION. Diffusion-related MRI parameters are useful for the early prediction of therapeutic response after cytotoxic chemotherapy for liver metastasis from CRC.