This paper reports a study of complex focussing acoustic fields of a convex phased array probe widely used in ultrasonic diagnostic B-scanner. The time delay necessary for electronic focussing and for geometric focuss...This paper reports a study of complex focussing acoustic fields of a convex phased array probe widely used in ultrasonic diagnostic B-scanner. The time delay necessary for electronic focussing and for geometric focussing of complex focussing is given. By means of Helmholtz's integral formula, the expressions of acoustic fields were obtained for the electronic focussing and complex focussing.With Simpson's numerical integral, a great deal of computations was carried out with an 86 / 330 computer. By means of using different parameters, an optimum focal range and beam width of a 4 sequences electronic and complex focussing acoustic system was selected. With an EUB-40 ultrasound diagnostic B-scanner produced by the Hitachi company, the lateral focussing acoustic field and lateral resolution in an echoic tank were photographed by latticing method and the experimental result is consistent with the theory.展开更多
Objective To investigate the role of dobutamine stree echocardiography in evaluating cardiac betaadrenergic receptor (AR) function and responsive ness in children Methods Left ventricular ejection fraction (EF), fr...Objective To investigate the role of dobutamine stree echocardiography in evaluating cardiac betaadrenergic receptor (AR) function and responsive ness in children Methods Left ventricular ejection fraction (EF), fractional shortening (FS), left ventricular end systolic volume index (ESVI), the ratio of systolic b lood pressure and ESVI (SP/ESVI) were measured by dobutamine stress echocardiogr aphy (DSE) in 30 children with AR hypersensitivity, 15 children with dilated cardiomyopathy and 30 normal children respectively Results Before pharmacological stress, EF and FS were 072 and 039 r es pectively in AR hypersensitivity group versus 070 and 035 respectively i n control group There was no difference of the indices between the two groups ( P >005) SP/ESVI was 076, higher than the value of 066 in co ntro l group ( P <005); EF, FS and SP/ESVI were 041, 015 and 01 0 re spectively, which were significantly lower than those in control group After d o butamine stress of 5?gkg-1min-1 and 10?gkg-1min -1, EF, FS and SP/ESVI were sig nificantly increased in patients with AR hypersensitivity and there were no changes in children with dilated cardiomyopathy compared with values of baseline Conclusion Cardiac AR function and responsiveness can be evaluated by dobutamine stress echocardiography展开更多
文摘This paper reports a study of complex focussing acoustic fields of a convex phased array probe widely used in ultrasonic diagnostic B-scanner. The time delay necessary for electronic focussing and for geometric focussing of complex focussing is given. By means of Helmholtz's integral formula, the expressions of acoustic fields were obtained for the electronic focussing and complex focussing.With Simpson's numerical integral, a great deal of computations was carried out with an 86 / 330 computer. By means of using different parameters, an optimum focal range and beam width of a 4 sequences electronic and complex focussing acoustic system was selected. With an EUB-40 ultrasound diagnostic B-scanner produced by the Hitachi company, the lateral focussing acoustic field and lateral resolution in an echoic tank were photographed by latticing method and the experimental result is consistent with the theory.
文摘Objective To investigate the role of dobutamine stree echocardiography in evaluating cardiac betaadrenergic receptor (AR) function and responsive ness in children Methods Left ventricular ejection fraction (EF), fractional shortening (FS), left ventricular end systolic volume index (ESVI), the ratio of systolic b lood pressure and ESVI (SP/ESVI) were measured by dobutamine stress echocardiogr aphy (DSE) in 30 children with AR hypersensitivity, 15 children with dilated cardiomyopathy and 30 normal children respectively Results Before pharmacological stress, EF and FS were 072 and 039 r es pectively in AR hypersensitivity group versus 070 and 035 respectively i n control group There was no difference of the indices between the two groups ( P >005) SP/ESVI was 076, higher than the value of 066 in co ntro l group ( P <005); EF, FS and SP/ESVI were 041, 015 and 01 0 re spectively, which were significantly lower than those in control group After d o butamine stress of 5?gkg-1min-1 and 10?gkg-1min -1, EF, FS and SP/ESVI were sig nificantly increased in patients with AR hypersensitivity and there were no changes in children with dilated cardiomyopathy compared with values of baseline Conclusion Cardiac AR function and responsiveness can be evaluated by dobutamine stress echocardiography
