Ultrasonic Tissue Characterization of Atherosclerosis by a Speed-of-Sound Microscanning System

Abstract

We have been developing a scanning acoustic microscope (SAM) system for medicine and biology featuring quantitative measurement of ultrasonic parameters of soft tissues. In the present study, we propose a new concept sound speed microscopy that can measure the thickness and speed of sound in the tissue using fast Fourier transform of a single pulsed wave instead of burst waves used in conventional SAM systems. Two coronary arteries were frozen and sectioned approximately 10 m in thickness. They were mounted on glass slides without cover slips. The scanning time of a frame with 300 300 pixels was 90 s and twodimensional distribution of speed of sound was obtained. The speed of sound was 1680 30 m/s in the thickened intima with collagen fiber, 1520 8 m/s in the lipid deposition underlying the fibrous cap, and 1810 25 m/s in a calcified lesion in the intima. These basic measurements will help in the understanding of echo intensity and pattern in intravascular ultrasound images.

Acoustic characteristics of fatty and fibrotic liver measured by an 80-MHz and 250 MHz scanning acoustic microscopy

“…An adjacent 10-μm thin section was placed on a microscope slide and scanned using a modified scanning acoustic microscope (AMS-50SI; Honda Elec. [1,2]) incorporating transducers operating at 80-and 250-MHz center frequencies. The 80-MHz transducer (Toray Eng.)…”

Carotid atherosclerotic plaque characterisation by measurement of ultrasound sound speed in vitro at high frequency, 20MHz

“…Chapter 1: Saijo et al (1998Saijo et al ( , 2004Saijo et al ( , 2006Saijo et al ( , 2007. Calibrated velocity test object.…”

“…Later studies investigated the acoustic properties of both normal and atherosclerotic coronary artery Saijo et al 2007). The results from this work is summarised in table 1.…”

Ultrasound monitoring of temperature and coagulation change during tumor treatment with microwave ablation

“…Ultrasonic tissue characterization can also be used to detect small pathological changes in the tumor in addition to observe its size, movement, and the neighboring structure. Therefore, this technique is of important clinical value (Huang et al, 2007;Lai et al, 2007;Mehdi et al, 2007;Saijo et al, 2007).…”