BME Professor Steve McAleavey Awarded PumpPrimer II Grant

April 29, 2015

BME Professor Steve McAleavey has been awarded a University of Rochester PumpPrimer II grant for his research project titled “Towards Diagnostic Ultrasonic Imaging of Tissue Non-Linearity: Strain Dependence of Shear Wave Velocity in Liver and Breast Tissue.” 

This project is a first step towards a long-term goal of characterizing non-linear mechanical properties of tissues non-invasively and in vivo with ultrasound, with application to clinical disease monitoring as well as basic research. 

Current tissue elastography systems characterize tissue under the simplifying assumption that it is a linear elastic material. Real tissues are viscoelastic (lossy) and non-linear – their apparent stiffness is dependent on the degree to which they are deformed. The McAleavey lab has developed significant improvements in methods for quantifying the viscoelastic characteristics of tissue. 

Biopsy is the standard for diagnosing breast cancer and liver fibrosis. However, biopsies come at a cost – in monetary terms as well as patient health and anxiety. For instance, breast biopsies are often (75-80%) negative; the ability to improve confidence in classification breast lesions could allow more patients to be followed up rather than biopsied, avoid needless anxiety, and lead to significant reductions in health care costs. There is strong evidence that malignant and benign lesions of the breast can be differentiated based on their non-linear mechanical properties, e.g. nonlinear shear modulus and strain dependent shear wave velocity.

Similarly, while elastography has shown promise for non-invasive staging of liver fibrosis, it is currently limited in its ability to distinguish early stages of fibrosis, when this ability would be most useful. Liver biopsy carries significantly more risk and cost than breast biopsy and is not suitable for patient monitoring. Liver is known to have strongly non-linear mechanical properties, which can confound the ability of elastography to stage fibrosis. The goal of the McAleavey lab in this area is to develop systems and methods that incorporate tissue non-linearity and yield a more precise staging of fibrosis.