Relationship between myocardial tissue density measured by microgravimetry and sound speed measured by acoustic microscopy

• Published in: Ultrasound in medicine & biology Vol. 25; no. 9; pp. 1459 - 1463
• Main Authors: Masugata, Hisashi, Mizushige, Katsufumi, Senda, Shoichi, Kinoshita, Aki, Sakamoto, Haruhiko, Sakamoto, Seiji, Matsuo, Hirohide
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.11.1999; Elsevier
• Subjects: Acoustic microscopes; Acoustic microscopy; Acoustics; Aged; Amyloidosis - pathology; Amyloidosis - physiopathology; Biological and medical sciences; Bulk modulus; Cardiomyopathies - pathology; Cardiomyopathies - physiopathology; Cardiovascular system; Densitometry - methods; Density; Density measurement (specific gravity); Elasticity; Gravimetric analysis; Heart - physiology; Heart - physiopathology; Humans; Hypertrophy, Left Ventricular - pathology; Hypertrophy, Left Ventricular - physiopathology; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; Middle Aged; Myocardial tissue; Myocardium - cytology; Sound speed; Tissue; Ultrasonic investigative techniques; Ultrasonic velocity; Elasticity; Myocardial tissue; Acoustic microscopy; Density; Bulk modulus; Sound speed; Heart; Human; Cardiovascular disease; Case control study; Conduction velocity; In vitro; Measurement technique; Heart disease; Myocardium; Circulatory system; Elastic properties; Microgravity; Ultrasound; Comparative study; Hypertrophy
• ISSN: 0301-5629; 1879-291X
• DOI: 10.1016/S0301-5629(99)00091-5

If myocardial tissue can be assumed to be fluid-like, myocardial tissue elasticity can be estimated by the sound speed of tissue based on the equation K= ρc 2, where K is the elastic bulk modulus, ρ is density, and c is the sound speed of tissue. However, little data exist regarding the relationship between the sound speed of tissue and tissue density. The purpose of the present study was to evaluate the relationship between the sound speed of tissue and tissue density of various diseased myocardia. Myocardial tissue specimens at autopsy were obtained from 10 control patients without cardiovascular disease, 8 patients with pressure overload left ventricular hypertrophy (POLVH), and 8 patients with cardiac amyloidosis (AMD). Myocardial tissue sound speed was measured using a scanning acoustic microscope operating in the frequency of 450 MHz, and tissue density was measured by microgravimetry. The sound speed in POLVH (1639 ± 17 m/s) was higher and that in AMD (1565 ± 11 m/s) was lower than that in control patients (1615 ± 15 m/s) ( p < 0.001) at the temperature of 20–22°C. The density in POLVH (1.087 ± 0.004 g/cm 3) was higher and that in AMD (1.072 ± 0.003 g/cm 3) was lower than that in control patients (1.082 ± 0.003 g/cm 3) ( p < 0.001). Tissue density correlated with sound speed in all three groups ( r = 0.96, p < 0.001). Therefore, myocardial tissue sound speed data obtained by acoustic microscopy enabled us to evaluate tissue elasticity without measuring tissue density directly.