P900 The Heart Model: Automated LVEF calculation in the real world

Background

Heart Model (HM) is a proprietary, model-based algorithm for measurement of left ventricular ejection fraction (LVEF) in a 3D dataset acquired from an apical 4-chamber view by transthoracic echocardiography (TTE). There is evidence for superior reproducibility compared to 2D echo methods for LVEF measurement.

Objective

To assess the correlation of LVEF by HM with conventional, 2D LVEF methods.

Methods

All TTEs performed between 04-08/02/2019 by 2 HM-trained sonographers were included. Demographic characteristics, indication for TTE, LVEF by Simpson"s (LVEF_S), by "eyeballing" (LVEF_EB) and by HM (LVEF_HM), were recorded; LVEF for each study was also estimated by eye-balling by an experienced observer unaware of the reported LVEF (LVEF_IND). We compared LVEF by each method, their reciprocal correlations and their correlation with LVEF_HM. Image quality was rated excellent (endocardial border visible for all segments in the 3 apical views), good (< 1 segment was not visible / view), adequate (< 3 segments were not visible) and limited (<4 segments were not visible). Indications for TTE were: assessment of LVEF in 1/3 of the studies, murmurs in 1/5, and other indications in the rest.

Results

We included 74 patients (42 M, mean age (SD) 69.8(13.9), range 18-92 years). Forty-nine (66%) patients were in sinus rhythm, 23 (31%) were in AF, and the rest were in various paced rhythms. Fifty patients (68%) had excellent, good or adequate images. The EFs calculated by different methods are shown in the Table (p > 0.05 for all), an the Bland Altman plot (LVEF_EB vs HM) in the figure. LVEF_HM correlated modestly with the other methods if all studies were included (r = 0.535 LVEF_HM vs. LVEF_EB); the correlation improved if only good-quality studies were included (r = 0.769, p < 0.001 for both). All combinations of LVEF_IND, LVEF_EB and LVEF_S had correlation coefficients >0.93.

Conclusions

The Heart Model algorithm for LVEF measurement correlates well with traditional 2D methods in patients with good endocardial border definition, where its use can potentially improve reproducibility and reduce exam duration.

LVEF by method (good-quality studies) N = 50 Simpson"s Eyeballing HeartModel Independent Mean(%) 48.6 48.9 50.9 48.8 SD(%) 17.8 16.6 14.9 15.7 Median(%) 54.5 52.5 53 50 Range(%) 16-74 17.5-72.5 19-88 15-75 SD - standard deviation Independent - LVEF estimate (eyeballing) by independent observer unaware of reported EFs. LVEF_EB was chosen as it was available inall the reports.

Abstract P900 Figure. Bland Altman Plot (LVEF_EB vs LVEF_HM)

Shape transitions between and within Zr isotopes

The Zirconium isotopes across the N=56,58 neutron sub­shell closures have been of special interest since years, sparked by the near doubly-magic features of 96Zr and the subsequent rapid onset of collectivity with a deformed ground-state structure already in 100Zr. Recent state-of-the-art shell model approaches did not only correctly describe this shape-phase transition in the Zr isotopic chain, but alsothe coexistence of non-collective structures and pronounced collectivity especially in 96,98Zr. Theisotope 98Zr is located on the transition from spherical to deformed ground state structures. We summarize recent experimental work to obtain the B(E2) excitation strengths of the first 2+ state of98Zr, including a new experiment employing the recoil-distance Doppler-shift method following a two-neutron transfer reaction.

Student Perceptions of Motor, Mental and Social Benefits and the Impact of Practicing Recreational Figure Skating

The study aims to highlight the impact of practicing recreational figure skating by evaluating the relationship between the perceptions of motor, mental and social benefits of practicing figure skating and the frequency and duration allocated for this recreational activity. The study included 143 students of physical education and sport specialization. The questionnaire was designed to evaluate the students' perception about the benefits of practicing recreational figure skating; it included 30 items divided in three parts: motor, mental and social benefits. Each of them contained 10 items to be assessed by students using the Likert scale, with 2 items related to the duration and frequency of practicing figure skating during recreational time. The results were processed using SPPS 24. The results were statistically significant at p < 0.05. The Cronbach's Alpha coefficient of the questionnaire was α = 0.965, suggesting that the items had high internal consistency. Using the Likert scale, we found the following: concerning the high score 5 points-the motor capacity 62.9%, the mental capacity 49.7%, the social capacity 49.7%; and for a low score of 1 point-mental and social capacity 1.4%, motor capacity 0.7%. The effect size was medium for almost all items. No statistically significant correlations were found between the result of the questionnaire and the frequency and duration of practicing figure skating during free time. Figure skating is considered by students to be one of the activities through which a series of parameters of physical development and level of physical fitness can be improved through the expansion of motor skills. Also, the practice of figure skating contributes to the formation of proactive behaviors by improving the mental and social abilities of practitioners.

Multifaceted Quadruplet of Low-Lying Spin-Zero States in ^{66}Ni: Emergence of Shape Isomerism in Light Nuclei

A search for shape isomers in the ^{66}Ni nucleus was performed, following old suggestions of various mean-field models and recent ones, based on state-of-the-art Monte Carlo shell model (MCSM), all considering ^{66}Ni as the lightest nuclear system with shape isomerism. By employing the two-neutron transfer reaction induced by an ^{18}O beam on a ^{64}Ni target, at the sub-Coulomb barrier energy of 39 MeV, all three lowest-excited 0^{+} states in ^{66}Ni were populated and their γ decay was observed by γ-coincidence technique. The 0^{+} states lifetimes were assessed with the plunger method, yielding for the 0_{2}^{+}, 0_{3}^{+}, and 0_{4}^{+} decay to the 2_{1}^{+} state the B(E2) values of 4.3, 0.1, and 0.2 Weisskopf units (W.u.), respectively. MCSM calculations correctly predict the existence of all three excited 0^{+} states, pointing to the oblate, spherical, and prolate nature of the consecutive excitations. In addition, they account for the hindrance of the E2 decay from the prolate 0_{4}^{+} to the spherical 2_{1}^{+} state, although overestimating its value. This result makes ^{66}Ni a unique nuclear system, apart from ^{236,238}U, in which a retarded γ transition from a 0^{+} deformed state to a spherical configuration is observed, resembling a shape-isomerlike behavior.

Influence of Light-curing Parameters on Biofilm Development and Flexural Strength of a Silorane-based Composite

Objectives: The aim of this study was to evaluate the differences in biological and mechanical performances of a silorane-based and a methacrylate-based composite. Another aim was to assess the influence of light-curing time and light-curing intensity on in vitro biofilm formation and flexural strength of the two tested composites.

Methods: Experiment 1: 432 specimens obtained from a silorane-based composite and from a standard methacrylate-based composite were divided into six groups and light-cured for 10, 20, 30, 40, 60, or 80 seconds, using one of two light-curing intensities, 400 mW/cm2 or 800 mW/cm2. At 24 hours, a monospecific Streptococcus mutans biofilm adherent to the surfaces of the samples was obtained. Then, a colorimetric technique (MTT assay) was used to evaluate the adherent viable biomass. Two samples per group were observed using confocal laser scanning microscopy. Analysis of variance (ANOVA) and Tukey tests were used to analyze the results (p&lt;0.05). Experiment 2: 192 bar-shaped specimens were obtained and light-cured as in the previous experiment. A three-point bend test using a universal testing machine was performed to obtain flexural strength values. ANOVA and Tukey tests were used to analyze the results (p&lt;0.05).

Results: In experiment 1, a highly significant difference (p&lt;0.0001) in biofilm development was shown between silorane-based and methacrylate-based composites. In fact, the silorane-based composite exhibited better biological performance. Significant differences were also found between the two light-curing intensities (p&lt;0.018) and for curing times (p&lt;0.0001): silorane-based composite light-cured for 80 seconds at 800 mW/cm2 light-curing intensity showed the lowest biofilm development. In experiment 2, a significant difference in flexural strength (p&lt;0.0318) was only found between the different composites. Nevertheless, both resin composites showed flexural strength values in accordance with International Organization for Standardization guidelines even after 10 seconds of light-curing time.

Conclusions: Silorane-based composite was less prone to biofilm development compared with a methacrylate-based composite. Acceptable flexural strength values for both composites were obtained after 10 seconds of light-curing time.