CEE Seminar - From Cavity Expansion to Clinical Diagnosis

The mechanical properties of biological tissues change over time and with disease progression. Quantifying these mechanical properties can thus be instrumental for medical diagnosis and for evaluation of tissue viability for transplant. However, it is exceptionally challenging to mechanically characterize soft and biological materials using conventional testing methods, especially in-vivo. In recent years, volume controlled cavity expansion (VCCE) has emerged as a powerful needle-based method for quantifying the nonlinear properties of soft materials in-situ. In this talk, after briefly revisiting the fundamentals of VCCE, I will describe the translation of VCCE into Digital Palpation (DP); a minimally invasive diagnostic tool offering a quantitative alternative to a clinician's sense of touch. I will describe the application of DP for testing in human tissue and will focus on an ex-vivo study of 35 tests in freshly resected human thyroid nodules. I will show how data from this rapid and minimally invasive mechanical test enables separation between benign and malignant nodules of this highly prevalent cancer and can even hint at resolving oncocytic and follicular sub-types that routinely confound existing diagnosis methods. At present, up to one third of thyroid nodules cannot be decisively classified, leading to avoidable surgical removal of the thyroid gland. We hope that these results can, in the future, help to reduce the large fraction of thyroidectomies (40-70%) that ultimately prove benign and thus avoidable; potentially relieving patients from the potential life-long implications of surgical complications and hormone replacement, and paving the way for the diagnosis of additional diseases.