A New Tissue Resonator Indenter Device and Reliability Study

Ming Jia,Alireza Hariri,Jean W Zu

doi:10.3390/s110101212

Abstract

Knowledge of tissue mechanical properties is widely required by medical applications, such as disease diagnostics, surgery operation, simulation, planning, and training. A new portable device, called Tissue Resonator Indenter Device (TRID), has been developed for measurement of regional viscoelastic properties of soft tissues at the Bio-instrument and Biomechanics Lab of the University of Toronto. As a device for soft tissue properties in-vivo measurements, the reliability of TRID is crucial. This paper presents TRID’s working principle and the experimental study of TRID’s reliability with respect to inter-reliability, intra-reliability, and the indenter misalignment effect as well.

Highlights

The measurement of soft tissue mechanical properties is useful in many applications
Reliability of Tissue Resonator Indenter Device (TRID) is crucial and should be investigated before TRID being developed as a consumer product in the real world
The experimental results show that indenter misalignment has extremely small effect on TRID’s measurements of soft tissue dynamic properties, which means TRID can be developed as a reliable clinical application for diagnostics of disease

Summary

Introduction

The measurement of soft tissue mechanical properties is useful in many applications. For centuries, physicians have used palpation as an important diagnostic tool. If an external system with known natural frequencies and damping ratios comes into contact with a soft tissue under study, a shift will be observed in its natural frequencies and its damping ratios will increase This simple idea is the underlying principle based on which TRID works. When a soft tissue, which is assumed as a Kelvin model [17], comes into contact with the indenter tip of the device, its viscoelastic properties will be felt through the shift in the natural frequencies and damping ratios of the device. The amplified signal is applied to a voice coil actuator inside the mechanical system This produces motion in the indenter tip of the device to excite the attached tissue with extremely small amplitude. The experimental study of TRID’s reliability with respect to inter-reliability, intra-reliability, and the indenter misalignment effect is performed

Theoretical Fundament of Measurement

Experimental Study of Indenter Misalignment

Experimental Study of Inter-Reliability and Intra-Reliability

Conclusions