[Ultrasonic tissue characterisation in cardiology]

Ultrasonic tissue characterization is a relatively new non-invasive examination method the application of which in cardiology is steadily increasing. It is therefore the objective of the present work to summarize hitherto assembled knowledge on the use of this method in clinical practice. Ultrasonic tissue characterization uses scattering of ultrasonic waves which penetrate into the heart muscle. This scatter is due to particles inside the heart muscle, their size being smaller than the wave length of the incident ultrasonic undulation. Evaluation of the intensity of the backscatter makes it possible to evaluate structural and functional changes of the examined cardiac tissue. Ultrasonic tissue characterization is so far used in cardiology for evidence of myocardial ischaemia, for evaluation of structural myocardial changes with hypertrophic cardiomyopathy, to detect rejection after transplantation of the heart and in the diagnosis of myocarditis. Other possibilities for application of this method is assessment of the viability of the heart muscle, quantification of the amount of fibrous tissue in the heart muscle and differentiation of acute from chronic vegetation in patients with infectious endocarditis. Due to some limitations ultrasonic tissue characterization is in the majority of the mentioned indications rather a subsidiary method which can supplement the diagnosis and make it more accurate. Its future position will obviously depend on further technical improvement and simplification.