Value of ADC measurements for nodal staging after chemoradiation in locally advanced rectal cancer - A per lesion validation study

Abstract

Objectives: To evaluate the performance of diffusion-weighted MRI (DWI) in addition to T2-weighted (T2W) MRI for nodal restaging after chemoradiation in rectal cancer. Methods: Thirty patients underwent chemoradiation followed by MRI (1.5 T) and surgery. Imaging consisted of T2W-MRI and DWI (b0, 500, 1000). On T2W-MRI, nodes were scored as benign/malignant by two independent readers (R1, R2). Mean apparent diffusion coefficient (ADC) was measured for each node. Diagnostic performance was compared for T2W-MRI, ADC and T2W+ADC, using a per lesion histological validation. Results: ADC was higher for the malignant nodes (1.43∈±∈0.38 vs 1.19∈±∈0.2710-3 mm2/s, p∈