Quantitative ultrasound has been widely used for tissue characterization. In this paper we propose a new approach for tissue compression assessment. The proposed method employs the relation between the tissue scatterers’ local spatial distribution and the resulting frequency power spectrum of the backscattered ultrasonic signal. We show that due to spatial distribution of the scatterers, the power spectrum exhibits characteristic variations. These variations can be extracted using the empirical mode decomposition and analyzed. Validation of our approach is performed by simulations and in-vitro experiments using a tissue sample under compression. The scatterers in the compressed tissue sample approach each other and consequently, the power spectrum of the backscattered signal is modified. We present how to assess this phenomenon with our method. The proposed in this paper approach is general and may provide useful information on tissue scattering properties.
T h e a i m: The aim of the study is to present the initial experience with continuous flow left ventricle assist device (CF-LVAD) in pediatric patients with BSA below 1.5 m2. M a t e ri a l a n d M e t h o d s: Between 2016 and 2017, CF-LVAD (the Heartware System) have been implanted in three pediatric patients in the Department of Pediatric Cardiac Surgery, Jagiellonian University, Krakow, Poland. The indications for initiating CF-LVAD were end-stage congestive heart failure due to dilated cardiomyopathy in all children. R e s u l t s: Implanted patients have had BSA of 1.09, 1.42, 1.2 m2, and 37, 34, 34 kg of body weight and the age 12, 11, 12 years, respectively. The time of support was 550 days in two patients and 127 in another one, and is ongoing. The main complication has been driveline infection. C o n c l u s i o n: The outcomes from our single-center experience using the HeartWare CF-LVAD have been excellent with a low incidence of complication and no necessity to reoperation in our patients. Children could be successfully and safely discharged home.
The paper presents the characteristics of shallow groundwaters of the Polesie National Park – one of five national parks in Poland, where main subjects of protection are water-peatland ecosystems. Its functioning depends on the state of water resources. Data from field mapping at the turn of July and August 2013 used for the analysis show untypically high location of groundwaters in the summer period. Such a situation was caused by abundant atmospheric alimentation that occurred in spring and early summer of the analysed year.