Effects of multi-vendor gradient non-linearity correction on breast tumor ADC measurements in the ACRIN 6698 trial

Motivation: MRI scanner gradient non-linearity (GNL) is a known source of variability and spatially-dependent bias in quantitative ADC measurements derived from diffusion-weighted imaging (DWI). Goal(s): Evaluate the effects of GNL correction on DWI from the ACRIN 6698 multi-center trial, which investigated ADC as a marker breast cancer response in patients receiving neoadjuvant therapy. Approach: Retrospective GNL correction was performed on the ACRIN 6698 DWI dataResults: Percent decrease in mean tumor ADC post-GNC ranged from 0.5%-11% for different MRI gradient sets, illustrating that GNL can confer significant bias to ADC measurements and should be corrected in multi-center clinical DWI trials.Impact: Implementation of gradient non-linearity correction to reduce bias and variability of tumor ADC measurements from DWI data acquired in multi-center, multi-platform oncology trials may improve the quantitative utility of ADC for characterizing response to treatment.