Multimodal ultrasound microscopy for biomedical imaging

Acoustic microscopy provides not only high resolution imaging but also basic data for interpreting clinical ultrasound images and information on biomechanics of the tissues. Multimodal ultrasound microscope is developed for quantitative measurement of sound speed of the tissue. The frequency dependent characteristics of the amplitude and phase of a single pulse deduce the tissue thickness and sound speed. Specific acoustic impedance and elastic bulk modulus are derived by the sound speed and density of the tissue. Ultrasound impedance microscope visualizes microscopic image of the tissue surface by just touching the probe to the tissue. The reflection from the interface between the tissue and plastic plate is obtained to visualize two-dimensional distribution of specific acoustic impedance of the tissue. The multimodal ultrasound microscope realized conventional C-mode, surface impedance mode, B-mode, 3D mode and combination of photoacoustic imaging. The series of the ultrasound measurements of gastric cancer, renal cancer, prostatic cancer, myocardial infarction, atherosclerosis, cartilage-bone complex and brain have provided important information for clinical ultrasound imaging and pathophysiology from the point of view of biomechanics. Development of higher frequency transducer or arrayed transducer with newest technologies would realize higher resolution imaging and easier handling.