Quantitative Synthetic MRI in Body Imaging: Technical Basis, Current Applications, and Future Directions.

Quantitative synthetic MRI (SyMRI) enables simultaneous acquisition of quantitative T1, T2, and proton density maps and retrospective generation of multiple contrast-weighted images from a single acquisition. By moving beyond conventional qualitative MRI, SyMRI may improve workflow efficiency while providing objective tissue biomarkers. Although most extensively studied in neuroimaging, its application to body MRI has expanded rapidly. This narrative review summarizes the technical basis of body SyMRI, focusing on the predominant 2-dimensional QRAPMASTER/multidynamic multiecho (MDME) framework and the newer 3-dimensional quantification using an interleaved Look-Locker acquisition sequence with T2 preparation pulse (QALAS) approach, and discusses current evidence across breast, prostate, gynecologic, rectal, head and neck, and musculoskeletal imaging. Available studies indicate that SyMRI is technically feasible across these applications and shows promise for lesion characterization, tumor grading, prognostic assessment, treatment-response evaluation, and quantitative analysis of normal and diseased tissues. In several settings, SyMRI-derived parameters provide additional value when combined with diffusion-weighted imaging, dynamic contrast-enhanced MRI, clinicopathologic variables, histogram analysis, radiomics, and predictive modeling. However, current evidence remains limited by small, single-center, and methodologically heterogeneous studies, and most body applications still rely on two-dimensional implementations. Future progress will depend on multicenter prospective validation, standardization of quantitative workflows, and broader evaluation of newer three-dimensional methods.