Chengjie Ruan

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In this study, each peak/valley of a heart sound was modeled by a Gaussian curve and characterized by amplitude, timing, and supporting width. This model was applied to analyze the morphological variations induced by respiration in 12 subjects. It was observed that the morphology exhibited regular behaviors with respiration. The amplitude of the prominent(More)
The relationships between the amplitude of the first heart sound (S1) and the rising rate of left ventricular pressure (LVP) concluded in previous studies were not consistent. Some researchers believed the relationship was positively linear; others stated the relationship was only positively correlated. To further investigate this relationship, this study(More)
PURPOSE Apparent patient size in CT localizers varies with localizer type and patient positioning, resulting in variation in effective mAs as guided by Tube Current Modulation (TCM). Our aim was to investigate the effects of vertical off-centering on CTDI-vol when using different localizer types and TCM strengths. METHODS A CTDI body phantom was scanned(More)
The previous studies on respiratory physiology have indicated that inspiration and expiration have opposite effects on heart hemodynamics. The basic reason why these opposite hemodynamic changes cause regular timing variations in heart sounds is the heart sound generation mechanism that the acoustic vibration is triggered by heart hemodynamics. It is(More)
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