Value of Diffusion Weighted Imaging (DWI) as an Early Imaging Biomarker for Prediction of Therapy Effect in Patients with Colorectal Metastases Following Selective Internal Radiotherapy (SIRT)

Martin Zeile¹, Christian Wybranski¹, David Loewenthal¹, Maciej Pech¹, Frank Fischbach¹, Ricarda Ruehl¹, Holger Amthauer¹, Jens Ricke¹, Oliver Dudeck¹

Clinical studies revealed the potential of diffusion weighted imaging (DWI) as a biomarker for predicting tumor response. 41 colorectal liver metastases in 18 patients who underwent SIRT were examined before, 1 to 3 days after and 6 weeks following radioembolization by MRI including DWI. Lesions were categorized in responding (RL) and non-responding (NRL) according to change in tumor volume after 6 weeks. On early MRI, NRL showed no change in apparent diffusion coefficient (ADC), while a significant decrease in ADC was noted for RL (p<0.0001). DWI was capable of predicting therapy response in patients with colorectal liver metastases following radioembolization.