Transmission acoustic microscopy of tissue sections (1 GHz)
SummaryThe acoustic microstructure of mouse small intestine has been studied with a transmission acoustic microscope working at 1 GHz and the influence of the histologic processing on the microacoustic pattern has been tested. Unstained thin sections provide pictures rich in details and highly contrasted. Gelatin has been used as hydrosoluble embedding medium and has been compared to paraffin. The former embedding procedure retained the viscoelastic properties of the specimen far more and provided the most detailed pictures. Osmiun tetroxide has been used to demonstrate acoustic staining.
Effects of tissue processing techniques in acoustical (1.2 GHz) and light microscopy
SummaryIn this study the influence of various tissue processing and staining techniques on the acoustical properties of liver tissue was investigated. A qualitative study was performed using ultrasound attenuation as the imaged parameter of a combined optical/acoustical microscope with a 1.2 GHz transducer. Images were made of three sets of adjacent liver sections (6 μm in thickness) which were prepared in ten different ways: fixed by alcohol or formalin; stained by hematoxylineosin (HE), toluidine blue (TB) or non-stained; sectioned by a cryostat or by a paraffin microtome. It was concluded that the images obtained from cryostat sections were of much higher quality than those from paraffin sections. Images obtained from sections that were sectioned while embedded in paraffin displayed no detail at all. No consistent effect was noticed with respect to staining by HE or TB. Alcohol fixed sections gave more detailed images than formalin fixed sections. Formalin fixation in combination with cryostat sectioning yielded many cytoplasmic vacuoles.
Ultrasonic tissue characterization: A Review
Present medical ultrasound systems are based on envelope detection methods and therefore display only echo intensity information. However, phase information is also recorded by the transducer which is a pressure‐sensitive device, but is not utilized in commercial display or measurement schemes. This additional information may be of diagnostic significance since the interaction between sound and tissue acoustical properties can be correlated with specific pathological states. Thus, in principle, in vivo techniques could be devised which would extract and separate the medically significant features of the ultrasound interactions with tissue and would display ultrasonic tissue signatures appropriate for a differential diagnosis. The development of such quantitative techniques for the measurement of ultrasonic tissue parameters and/or the display of ultrasonic tissue signatures has become known as ultrasonic tissue characterization. In this paper we review the physical basis for ultrasonic tissue characteriza...