Quantitative 3·D Echocardiography of The Heart and The Coronary Vessels

The recognition of the existence of ultrasound is credited to L. Spallanzani (1729- 1799). In recent years, ultrasound has been used as an imaging modality in medicine. I. Edler and C.H. Hertz produced the first ultrasound images of the heart in 1953. In the 1960's great progress was made in the clinical application of ultrasound when real-time two-dimensional ultrasound scanners were developed. In 1968, J. Somer constructed the first electronic phased-array scanner and this technology is still the most widely used in ultrasound equipment. In 1974 F.E. Barber and colleagues produced a duplex scanner which integrated imaging with pulsed-wave Doppler measurements. C. Kasai and colleagues constmcted in 1982 the color-coded Doppler flow imaging system based on autocorrelation detection, providing a noninvasive "angiogram" simulation of normal and abnormal blood flow on a "beat-to-beat" basis. Transesophageal echocardiography became available to clinicians in 1985 due to the developments of 1. Soquet who invented the mono- and biplane electronic phased-array probel Echocardiography has become one of the most commonly used diagnostic imaging techniques in cardiology. The development of commercial 3-D echocardiographic equipment began in the early 1990's. In 1993 a technique allowing acquisition of tomographic parallel sliced data set of echocardiographic images of the heart with a lobster tail TEE probe, was 2 developed by the German based company "TomTec GmbH". The TEE probe had an imaging element which could be controlled by computer applying a stepping motor. They also developed an interface to the patient to record the respiration and R-R intervals. This allowed the acquisition of ultrasound images ECG-triggered and gated, which reduced motion artifacts caused by beat-to-beat and respiratory variations in cardiac dimensions and position. After the acquisition of a tomographic data set, the images were post-processed and with application of software interpolation algorithms, gaps in the data set could be filled. This post-processed data set could then be used to reconstruct 3-D volume rendered images of the heart. 3-D ultrasound provides cardiac images which more closely mimic actual anatomy'than 2-D cross-sectional linages, and may thus be easier to interpret

Data reconciliation of immersive heart inspection

IVUS images are complicated medical datasets suffering from some artifacts caused by the data acquisition method of immersive heart inspection. Data reconciliation, which removes tracing and tracking uncertainties of these datasets, is an important step for the medical application of remodeling the arteries in virtual reality to aid diagnosing and treating heart diseases. This paper provides an empirical data reconciliation method, which fuses the features of the coronary longitudinal movement with motion compensation model. It explains the distortion of the data set well and provides a method to analyze and reconcile the dataset

The Impact of Business Ownership Change on Employee Relations: Buy-outs in the UK and the Netherlands

A buy-out is a fundamental change in the structure of ownership that may affect the way employee relations develop within an organisation. Little is known about the impact of buyouts upon employee relations. This paper aims to address this gap. We focus on two main questions. First, what are the effects of a buy-out on employee relations in an organisation? Second, does the national institutional context affect the impact of buy-outs on employee relations? The paper reports changes to employee relations in buy-outs in the contrasting institutional environments of the UK and the Netherlands. Overall, we find that buy-outs positively affect HR practices with increases in training, employee involvement, the number of employees and pay levels. The positive effects appear to be significantly stronger in a less institutionalised environment like the UK than the more institutionalised environment of the Netherlands. Buy-outs raised HRM practices in the UK to a level closer although still below that of Dutch buy-outs

Secondary electron emissions and dust charging currents in the nonequilibrium dusty plasma with power-law distributions

We study the secondary electron emissions induced by the impact of electrons on dust grains and the resulting dust charging processes in the nonequilibrium dusty plasma with power-law distributions. We derive new expressions of the secondary emitted electron flux and the dust charging currents that are generalized by the power-law q-distributions, where the nonlinear core functions are numerically studied for the nonextensive parameter q. Our numerical analyses show that the power-law q-distribution of the primary electrons has a significant effect on the secondary emitted electron flux as well as the dust charging currents, and this effect depends strongly on the ratio of the electrostatic potential energy of the primary electrons at the dust grain's surface to the thermodynamic energy, implying that a competition in the dusty plasma between these two energies plays a crucial role in this novel effect.Comment: 16 pages, 6 figures, 32 reference

Dynamic Three-Dimensional Echocardiography Offers Advantages for Specific Site Pacing

We have developed a novel technique for specific site pacing

Patient-specific image-based computer simulation for theprediction of valve morphology and calcium displacement after TAVI with the Medtronic CoreValve and the Edwards SAPIEN valve

AIMS: Our aim was to validate patient-specific software integrating baseline anatomy and biomechanical properties of both the aortic root and valve for the prediction of valve morphology and aortic leaflet calcium displacement after TAVI. METHODS AND RESULTS: Finite element computer modelling was performed in 39 patients treated with a Medtronic CoreValve System (MCS; n=33) or an Edwards SAPIEN XT (ESV; n=6). Quantitative axial frame morphology at inflow (MCS, ESV) and nadir, coaptation and commissures (MCS) was compared between multislice computed tomography (MSCT) post TAVI and a computer model as well as displacement of the aortic leaflet calcifications, quantified by the distance between the coronary ostium and the closest calcium nodule. Bland-Altman analysis revealed a strong correlation between the observed (MSCT) and predicted frame dimensions, although small differences were detected for, e.g., Dmin at the inflow (mean±SD MSCT vs. MODEL: 21.6±2.4 mm vs. 22.0±2.4 mm; difference±SD: -0.4±1.3 mm, p<0.05) and Dmax (25.6±2.7 mm vs. 26.2±2.7 mm; difference±SD: -0.6±1.0 mm, p<0.01). The observed and predicted calcium displacements were highly correlated for the left and right coronary ostia (R2=0.67 and R2=0.71, respectively p<0.001). CONCLUSIONS: Dedicated software allows accurate prediction of frame morphology and calcium displacement after valve implantation, which may help to improve outcome

The European Society of Cardiology - a digital educator.

The mission statement of the European Society of Cardiology (ESC) is "to reduce the burden of cardiovascular disease". The ESC is the leading scientific society for cardiovascular health care professionals across Europe and increasingly the world. Recognising the need for democratisation of education in cardiology, the ESC has for many years embraced the digital world within its education programme. As in all areas of medicine, the COVID-19 pandemic required an agile response to be able to continue to provide not only a digital congress but also education, training and assessment in an almost totally digital world. In this paper we will describe the digital learning activities of the ESC, the successes and the challenges of the transformation that has taken place in the last 18 months as well as an overview of the vision for education, training and assessment in the post-COVID digital era. We understand the need to provide a portfolio of educational styles to suit a diverse range of learners. It is clear that digital CME provides opportunities but it is likely that it will not entirely replace in-person learning. In planning for the future, we regard the provision of digital CME as central to fulfiling our mission

Dynamic 3D echocardiography in virtual reality

BACKGROUND: This pilot study was performed to evaluate whether virtual reality is applicable for three-dimensional echocardiography and if three-dimensional echocardiographic 'holograms' have the potential to become a clinically useful tool. METHODS: Three-dimensional echocardiographic data sets from 2 normal subjects and from 4 patients with a mitral valve pathological condition were included in the study. The three-dimensional data sets were acquired with the Philips Sonos 7500 echo-system and transferred to the BARCO (Barco N.V., Kortrijk, Belgium) I-space. Ten independent observers assessed the 6 three-dimensional data sets with and without mitral valve pathology. After 10 minutes' instruction in the I-Space, all of the observers could use the virtual pointer that is necessary to create cut planes in the hologram. RESULTS: The 10 independent observers correctly assessed the normal and pathological mitral valve in the holograms (analysis time approximately 10 minutes). CONCLUSION: this report shows that dynamic holographic imaging of three-dimensional echocardiographic data is feasible. However, the applicability and use-fullness of this technology in clinical practice is still limited

Adjustment method for mechanical Boston scientific corporation 30 MHz intravascular ultrasound catheters connected to a Clearview console. Mechanical 30 MHz IVUS catheter adjustment.

Intracoronary ultrasound (ICUS) is often used in studies evaluating new interventional techniques. It is important that quantitative measurements performed with various ICUS imaging equipment and materials are comparable. During evaluation of quantitative coronary ultrasound (QCU) software, it appeared that Boston Scientific Corporation (BSC) 30 MHz catheters connected to a Clearview ultrasound console showed smaller dimensions of an in vitro phantom model than expected. In cooperation with the manufacturer the cause of this underestimation was determined, which is described in this paper, and the QCU software was extended with an adjustment. Evaluation was performed by performing in vitro measurements on a phantom model consisting of four highly accurate steel rings (perfect reflectors) with diameters of 2, 3, 4 and 5 mm. Relative differences (unadjusted) of the phantom were respectively: 15.92, 13.01, 10.10 and 12.23%. After applying the adjustment: -0.96, -1.84, -1.35 and -1.43%. In vivo measurements were performed on 24 randomly selected ICUS studies. These showed differences for not adjusted vs. adjusted measurements of lumen-, vessel- and plaque volumes of -10.1 +/- 1.5, -6.7 +/- 0.9 and -4.4 +/- 0.6%. An off-line adjustment formula was derived and applied on previous numerical QCU output data showing relative differences for lumen- and vessel volumes of 0.36 +/- 0.51 and 0.13 +/- 0.31%. 30 MHz BSC catheters connected to a Clearview ultrasound console underestimate vessel dimensions. This can retrospectively be adjusted within QCU software as well as retrospectively on numerical QCU data using a mathematical model

In vivo variability in quantitative coronary ultrasound and tissue characterization measurements with mechanical and phased-array catheters

Background: Both mechanical and phased-array catheters are used in clinical trials to assess quantitative parameters. Only limited evaluation of the in vivo agreement of volumetrical measurements between such systems has been performed, despite the fact that such information is essential for the conduction of atherosclerosis regression trials. Methods and results: We prospectively evaluated the agreement in morphometric measurements and intravascular ultrasound (IVUS)-based plaque characterization between a 40 MHz rotating transducer (3.2 F Atlantis, Boston Scientific Corp.) and a 20 MHz phased-array catheter (2.9 F Eagle Eye, Volcano Therapeutics, Rancho Cordova, California) in 16 patients. Lumen (7.3 ± 2.0 mm2 vs. 6.7 ± 1.8 mm2, p = 0.001) and vessel (11.8 ± 3.3 mm2 vs. 11.0 ± 2.9 mm2, p = 0.02) cross-sectional areas (CSA) were significantly greater with the 20 MHz system. Plaque CSA measurements showed no significant difference between systems (4.4 ± 2.3 mm2 vs. 4.4 ± 2.1). The relative differences were less than 10% for the three variables. On IVUS-based tissue characterization (13 patients), calculated percentage hypoechogenic volume was significantly higher for the 20 MHz system (96.7 ± 2.38 vs. 88.4 ± 5.53, p < 0.0001). Conclusions: Quantitative IVUS analyses display significant catheter type-dependent variability. It is unclear whether the variability reflects overestimation of measurements with the phased-array or underestimation with the mechanical system. Although plaque burden measurements did not differ significantly between systems, it appears prudent to recommend the use of a single system for progression/ regression studies