Apparent diffusion coefficient derived from diffusion-weighted imaging to differentiate between tumor, tumor-adjacent and tumor-distant tissues in resectable rectal adenocarcinoma

To evaluate feasibility of apparent diffusion coefficient (ADC) at different b-values to differentiate between tumor, tumor-adjacent and tumor-distant tissues in rectal adenocarcinoma (RA).Seventy consecutive patients with RA undergoing preoperative diffusion-weighted imaging were retrospectively enrolled. ADCs of tumor, proximal tumor-adjacent tissue (PTA) and tumor-distant tissue (PTD), and distal tumor-adjacent tissue (DTA) and tumor-distant tissue (DTD) were calculated with b-values of 0 and 800 sec/mmMean ADC of tumor was lower than those of PTA, PTD, DTA and DTD; and mean ADCs of PTA and DTA were lower than those of PTD and DTD at all b-values, respectively (all P-values 0.001). ADC cut-offs of 1.089 × 10ADC can help differentiate between tumor, tumor-adjacent and tumor-distant tissues in RA.