Chemotherapy response monitoring of colorectal liver metastases by dynamic Gd-DTPA-enhanced MRI perfusion parameters and 18F-FDG PET metabolic rate

D. Vriens, H. van Laarhoven, J. van Asten, P. Krabbe, E. Visser, A. Heerschap, C. Punt, L. de Geus-Oei and W. Oyen

Department of Nuclear Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
Nov, 2009



In this study, we examined the in vivo relationship between functional tumor vasculature, determined by dynamic contrast-enhanced (DCE-) MRI, and tumor metabolism, determined by dynamic (18)F-FDG PET, during cytotoxic treatment of patients with colorectal liver metastases.Twenty-three patients underwent DCE-MRI (using gadolinium dimeglumine) and dynamic (18)F-FDG PET at baseline and after 3 treatment cycles, unless treatment was terminated because of toxicity. Parameters for vasculature (rate constant between extravascular extracellular space and blood plasma [k(ep)] and volume transfer constant [K(trans)]), extracellular space (v(e)), tumor size (the maximal axial diameter of each included lesion [MAD]), and metabolism (glucose metabolic rates [MR(glc)]) were derived, and changes during treatment were correlated. Overall survival (OS) and progression-free survival (PFS) served as outcome measures for the predictive abilities of pretreatment parameters and of treatment-related parameter changes.Pretreatment MR(glc) and MAD were individually predictive for OS and PFS. During treatment, K(trans) increased significantly, but this increase could not be confirmed in a lesion-by-lesion analysis. MR(glc) decreased significantly (P < 0.001). No correlations were found for changes in DCE-MRI parameters and DeltaMR(glc). No relationship was found between changes in DCE-MRI parameters and OS or PFS. DeltaMR(glc) was able to predict OS (P = 0.008) after correction for confounders.The efficacy of cytotoxic chemotherapy assessed by reduction in tumor metabolism does not depend on pretreatment properties of the tumor vasculature determined by DCE-MRI. Cytotoxic chemotherapy does not alter DCE-MRI-derived properties of tumor vasculature but decreases glucose consumption of tumor cells.