Predictive Value of Fast & Slow ADC Component Analysis for Rectal Cancer Response Monitoring After Neo-Adjuvant Radiochemotherapy: Initial Results.

Martijn Intven¹, Onne Reerink¹, Marielle E. P. Philippens¹

After neo-adjuvant radiochemotherapy (RCT) for locally advanced rectal cancer good pathological response correlates with good long term outcome. Reliable pathological response prediction is needed to enable safe omission of surgery in good responders. Diffusion weighted imaging showed already promising results in pathological response prediction. In this study tumour response was assessed with both fast and slow apparent diffusion coefficient (ADC) component analysis, which reflects the perfusion and diffusion contribution in the ADC value, respectively. 8 patients were analysed pre- and post-RCT. In both the fast and slow ADC values a larger increase correlated with a good pathological response.