Compact Tabletop Magnetic Resonance Elastography for Mapping Soft Tissue Viscoelasticity

Compact, cost-effective tabletop magnetic resonance elastography (ttMRE) is an emerging research tool for assessing bulk soft tissue biomechanics but still lacks spatially resolved imaging of viscoelastic properties in heterogeneous specimens like tumors. Here, we develop and validate ttMRE for quantifying intratumoral biomechanical heterogeneity in human colorectal liver metastasis (CRLM). We excite cylindrical, multifrequency shear waves and reconstruct viscoelastic maps using adaptive bandpass filters constrained by rheological Bessel-fit priors. In this way, we obtain biophysical markers that agree with ground-truth measurements in numerical and viscoelastic phantoms. In CRLM, shear-wave-speed and penetration-rate maps - proxies of stiffness and attenuation, respectively - as well as their derived interquartile range and Shannon entropy, suggest markedly less viscous, stiffer, and more biomechanical heterogeneous tissue in specimens from responders to chemotherapy versus non-responders, with heterogeneity metrics outperforming direct viscoelastic parameters in diagnostic accuracy. These findings establish compact, automated ttMRE as a low-cost, scalable platform for spatial biomechanical profiling and quantitative assessment of treatment response in bulky colorectal liver metastasis specimens.