Biomarkers in abdominal imaging.

Imaging biomarkers are parameters measurable with imaging methods used to detect, stage or grade disease or assess the response to treatment. Compared with biochemical or histological markers, imaging biomarkers have the advantage of remaining non-invasive and being spatially and temporally resolved. Imaging biomarkers are used in multiple abdominal diseases, including cancer. Anatomical imaging biomarkers such as the RECIST criteria are often insufficient for the early assessment of treatment response. Molecular imaging biomarkers may be used when targeting a receptor or enzyme overexpressed in a given disease. Their use remains limited because of their narrow target specificity. Functional biomarkers are increasingly used with positron-emission tomography, perfusion MRI, diffusion-weighted MRI and MR spectroscopy. They have an important potential to help in selecting the patients and assessing the response to new treatments. However, important efforts of validation and standardization remain to be done before the wide use of imaging biomarkers in abdominal diseases.