Development and multicenter validation of a multiparametric imaging model to predict treatment response in rectal cancer.

Objectives: To develop and validate a multiparametric model to predict neoadjuvant treatment response in rectal cancer at baseline using a heterogeneous multicenter MRI dataset.

Methods: Baseline staging MRIs (T2W (T2-weighted)-MRI, diffusion-weighted imaging (DWI) / apparent diffusion coefficient (ADC)) of 509 patients (9 centres) treated with neoadjuvant chemoradiotherapy (CRT) were collected. Response was defined as (1) complete versus incomplete response, or (2) good (Mandard tumor regression grade (TRG) 1-2) versus poor response (TRG3-5).

Sources of variation in multicenter rectal MRI data and their effect on radiomics feature reproducibility.

Objectives: To investigate sources of variation in a multicenter rectal cancer MRI dataset focusing on hardware and image acquisition, segmentation methodology, and radiomics feature extraction software.

Methods: T2W and DWI/ADC MRIs from 649 rectal cancer patients were retrospectively acquired in 9 centers. Fifty-two imaging features (14 first-order/6 shape/32 higher-order) were extracted from each scan using whole-volume (expert/non-expert) and single-slice segmentations using two different software packages (PyRadiomics/CapTk).

Evolutions in rectal cancer MRI staging and risk stratification in The Netherlands.

Purpose: To analyze how the MRI reporting of rectal cancer has evolved (following guideline updates) in The Netherlands.

Methods: Retrospective analysis of 712 patients (2011-2018) from 8 teaching hospitals in The Netherlands with available original radiological staging reports that were re-evaluated by a dedicated MR expert using updated guideline criteria. Original reports were classified as "free-text," "semi-structured," or "template" and completeness of reporting was documented.