The accuracy of whole-body magnetic resonance imaging (MRI) is sufficiently accurate to replace other tests for the diagnosis, staging, and treatment planning of colorectal cancer (CRC), according to an article published in BMJ, which summarized the research findings of a study published in The Lancet (Taylor S, et al. 2019).

Treatment options for CRC depend on the cancer stage and presence of metastases. Presently, staging pathways are based on a series of diagnostic imaging tests, which includes computerized tomography (CT), positron emission tomography/CT, and MRI, all of which differ in their usefulness for detecting metastases in different areas of the body. The study by Taylor and colleagues compared the diagnostic accuracy of whole-body MRI CRC staging pathways with the standard staging pathways by prospective analysis of 299 adults with a new diagnosis of CRC. Differences in staging times, extra testing, costs, and treatment decisions were also analyzed to compare whole-body MRI staging with standard staging.

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A comparison reference for a correct diagnosis was determined by an expert multidisciplinary review panel. For patients later confirmed to have metastatic disease, the whole-body MRI staging pathways and standard pathways were similar in sensitivity, with 67% sensitivity shown for whole-body MRI compared with 63% for standard pathways (difference 4%; 95% CI, -5% to 13%). No difference was found in specificity, with 95% shown for whole-body MRI compared with 93% for standard pathways (difference 2%; 95% CI, -2% to 6%). Rates of agreement between decisions made using either pathway and those made by the expert review panel were similar (96% for whole-body MRI and 95% for standard pathway). However, median number of days for the staging process was reduced with whole-body MRI compared with standard pathways (8 days; 95% CI, 6-9 vs 13 days; 95% CI, 11 to 15), and average per-patient costs were also reduced, with £216 for whole-body MRI (95% CI, £211 to £221), compared with £285 for standard pathway (95% CI, £260 to £310).

The authors conclude that the study results suggest that “whole-body MRI is accurate enough to replace other tests for diagnosis, staging, and planning treatment of CRC. The whole body MRI pathway gave similar results to current pathways in terms of identifying metastatic disease and resulted in the same treatment decisions. It also reduced the number of tests needed, sped up the staging process, and lowered the costs…. The findings support a change in practice and may inform future updates to relevant guidance.”


  1. Cook R, Davidson P, Martin R; NIHR Dissemination Centre. Whole body MRI is effective for identifying metastatic disease in colorectal cancer patients. BMJ. 2019;366:l5453.
  2. Taylor SA, Mallet S, Beare S, et al. Diagnostic accuracy of whole-body MRI versus standard imaging pathways for metastatic disease in newly diagnosed colorectal cancer: the prospective Streamline C trial. Lancet Gastroenterol Hepatol. 2019;4(7):529-537.