A New Criterion for Shear Wave Elastometric Assessment Using Modulus of Stiffness Difference between Object and Environment.

Ultrasound shear wave elastography is a modern method that is based on measuring the shear wave velocity making it possible to determine stiffness of soft biological tissues at an arbitrary point (point elastography) or to construct a two-dimensional color image with a subsequent point measurement of stiffness (two-dimensional elastography) and therefore to compare the stiffness of an object with a medium or objects with each other. The aim of the study is to develop a new criterion for the comparative assessment of objects with different stiffness during shear wave elastometry: modulus of stiffness difference between object and environment. Materials and Methods: Using the original technology of building two-dimensional color elastogram, point and two-dimensional shear wave elastography were performed using linear sensors on commercial ultrasound scanners: Aixplorer (SuperSonic Imagine, France), Acuson S2000 (Siemens, Germany), and Verasonics acoustic system (Verasonics Inc., USA) with an open architecture to determine the stiffness values of focal inclusions and compare them with each other with the help of a new comparative elastomeric assessment criterion: modulus of stiffness difference between object and environment. First, the accuracy of the scanners under test was compared on a calibrated Elasticity QA Phantom, model 049 (Computerized Imaging Reference Systems Company, USA) with a known stiffness of various inclusions and thereafter on an uncalibrated BP1901 phantom (Blue Phantom, USA) with unknown stiffness of inclusions. The obtained values were compared to determine the influence of subjective factors on the measurement results. Results: To assess the stiffness of the foci and compare the values with each other taking into account the rigidity of the environment, it is proposed to use a new criterion for the comparative assessment - the modulus of stiffness difference between focus and environment, which quantitatively characterizes the difference between these values. According to this criterion, all three ultrasound scanners have been established to show high and comparable accuracy in determining the stiffness of inclusions within the homogeneous medium in the experiments on phantoms. Two-dimensional shear wave elastography has revealed the effect of the control volume size and the correctness of the color scale setting, especially in the heterogeneous objects, on the results of elastometry. Methodological techniques to reduce the influence of subjective factors have also been proposed. Conclusion: The study has showed the possibility of using the modulus of stiffness difference between object and environment as a new criterion for comparative assessment of objects in shear wave elastometry taking into account stiffness of the environment. To reduce operator-dependence, it is necessary to take into consideration both the way of realizing elastometry (point or two-dimensional color elastography) and a number of other methodological factors.

[Focus ultrasound for cardiology practice. Russian consensus document].

This document is a consensus document of Russian Specialists in Heart Failure, Russian Society of Cardiology, Russian Association of Specialists in Ultrasound Diagnostics in Medicine and Russian Society for the Prevention of Noncommunicable Diseases. In the document a definition of focus ultrasound is stated and discussed when it can be used in cardiology practice in Russian Federation.

[Ultrasound study of the liver and kidneys after different types of resection].

The ultrasound pattern of hepatic and renal changes after different types of resection is depicted. Ultrasound studies were performed in 335 patients operated on for focal hepatic masses and in 72 patients operated on for focal renal masses. The authors identified 3 patient groups after hepatic resection (segment-oriented liver resection (99 patients), portal hemihepatectomy (n=163), and extended hemihepatectomy (n=73)) and 3 patient groups after renal resection (planar (n = 83), wedge (n = 104), and frontal (n = 66)). It has been established that the number and location of hepatic veins in the liver stump, which the authors have designated as a hepatic vein rule, are of basic value in defining the type of hepatic resection. To determine the type of renal resection, it is essential to assess the shape of the organ and the area of its resection. The found echosemiotic patterns allow the type of performed resection of parenchymatous organs to be correctly determined in the majority of cases.

[Ultrasonic diagnosis of subpleural parietal formations of the lung]. / Ul'trazvukovaia diagnostika subplevral'nykh pristenochnykh obrazovanii legkikh.

The article generalizes experiences with ultrasonic scanning of the chest in patients with subpleural parietal formations of the lungs of inflammatory and tumorous etiology. The technique of the investigation and criteria of the assessment of the pathological focus are described. The normal echoscopic picture of the chest was determined. The ultrasonic images of the abscesses were compared with those of the peripheral lung carcinoma. The echoscopic pictures typical of each disease were revealed.