Quantification of resting myocardial blood flow velocity in normal humans using real-time contrast echocardiography. A feasibility study

BACKGROUND: Real-time myocardial contrast echocardiography (MCE) is a novel method for assessing myocardial perfusion. The aim of this study was to evaluate the feasibility of a very low-power real-time MCE for quantification of regional resting myocardial blood flow (MBF) velocity in normal human myocardium. METHODS: Twenty study subjects with normal left ventricular (LV) wall motion and normal coronary arteries, underwent low-power real-time MCE based on color-coded pulse inversion Doppler. Standard apical LV views were acquired during constant IV. infusion of SonoVue(®). Following transient microbubble destruction, the contrast replenishment rate (β), reflecting MBF velocity, was derived by plotting signal intensity vs. time and fitting data to the exponential function; y (t) =A (1-e(-β(t-t0))) + C. RESULTS: Quantification was feasible in 82%, 49% and 63% of four-chamber, two-chamber and apical long-axis view segments, respectively. The LAD (left anterior descending artery) and RCA (right coronary artery) territories could potentially be evaluated in most, but contrast detection in the LCx (left circumflex artery) bed was poor. Depending on localisation and which frames to be analysed, mean values of [Image: see text] were 0.21–0.69 s(-1), with higher values in medial than lateral, and in basal compared to apical regions of scan plane (p = 0.03 and p < 0.01). Higher β-values were obtained from end-diastole than end-systole (p < 0.001), values from all-frames analysis lying between. CONCLUSION: Low-power real-time MCE did have the potential to give contrast enhancement for quantification of resting regional MBF velocity. However, the technique is difficult and subjected to several limitations. Significant variability in β suggests that this parameter is best suited for with-in patient changes, comparing values of stress studies to baseline

KnowledgeWar 2.0: A Pervasive Knowledge War Game

This thesis set out to study how a pervasive multiplayer lightweight Role-Playing Game could be used within higher education in order to motivate and engage students. The primary research goal was to study the educational effect of this type of game, while a secondary research goal was to experiment with HTLM5 and JavaScript to build a cross-platform friendly solution. The game was tested in two user experiments on voluntary students having taken the course Software Architecture at the Norwegian University of Science and Technology. Data from these user experiments were collected through a custom-made quantitative questionnaire and a System Usability Scale, as well as informal group discussions with the participants of the experiments. The results indicate that students found the game to be both fun and educational. However, results further indicate that the game need more of both gameplay and game world content, in order to "disguise" its educational content well enough to make students want to play the game regularly. The thesis concludes that more gameplay elements needs to be added to the game in order to fully reach its potential as both a pervasive game and a RPG game. By doing so the results indicate that the game has the potential to become a successful educational aid in higher education