A consistent pre-clinical/clinical elastography approach for assessing tumor mechanical properties in therapeutic systems

Unlike many other experimental imaging methods, elastography has enjoyed a strong link to the standard diagnostic and interventional evaluation technique of soft tissue palpation. As a result, the initial excitement about elastography quickly translated to clinical use (e.g., [1-3]) which now includes commercially available ultrasound and magnetic resonance (MR) elastography products. However, despite these advances, understanding what these macroscopic clinical-scale tissue measurements indicate with respect to the underlying cellular and tissue-matrix scale phenomena is largely unclear. In this work, we present preliminary data towards a more systematic study of the elasticity biomarker in characterizing cancer for therapeutic design and monitoring. In addition, we demonstrate that we can conduct these studies with techniques that are consistent across both pre-clinical (i.e., mouse) and clinical length scales. The elastography method we use is called modality independent elastography (MIE) [4, 5] and can be described as a highly translatable model-based inverse image-analysis method that reconstructs elasticity images using two acquired image volumes in a pre-post state of deformation. Quantitative phantom results using independent testing methods report an elastic property contrast between the inclusion and background as a 14.9 to 1 stiffness ratio with MIE reconstructing the ratio as 13.1 to 1. Preliminary elasticity reconstructions in murine and human systems are reported and are consistent with literature findings.