Effects of different ultrasound power application on left ventricular transmural displacement in vivo open‐chest Beagle canines / 中华超声影像学杂志

ABSTRACT

Objective To evaluate left ventricular ( LV ) myocardial mechanical transmural longitudinal displacement ( LD ) and radial displacement ( RD ) with contrast agent and different power irradiation in open‐chest Beagle canines by ultrasound velocity vector images ( VVI) workstation . Methods T he anesthetized open‐chest Beagle canines were assigned into two groups randomlyGroup A ( n ＝6) for baseline ,diagnostic ultrasound power irradiation ( 300 mW) 5 min ,combined with contrast agent irradiation 5 min and contrast agent 20 min conditions ; Group B ( n ＝ 6 ) for baseline and intensity ultrasound irradiation ( 1 W ,2 W and 3 W ,5 min respectively) conditions . T he standard short‐axis and long‐axis gray‐scale view s during three complete cardiac cycles in open‐chest Beagle canine models were acquired . T he peak LD subendomyocardium ( LD‐subendo) ,LD subepimyocardium ( LD‐subepi) ,RD subendomyocardium ( RD‐subendo) and RD subepimyocardium ( RD‐subepi ) of LV were analyzed using a dedicated Syngo VVI method . Results In group A ,the LV LD‐subendo ,LD‐subepi ,RD‐subendo and RD‐subepi in the most of segments showed increasing trend in diagnostic power irradiation ,contrast agent irradiation 5 min and contrast agent 20 min compared with baseline condition ,however the differences were not significant ( P ＞0 .05 ,respectively) . T he peak LD‐subendo and LD‐subepi ,RD‐subendo and RD‐subepi of LV in group A with the same condition were significant different ( all P ＜0 .05) . In group B ,LV LD‐subendo in ultrasonic power 3 W was lower than baseline condition ( P ＜ 0 .05 ) ,LV RD‐subendo was higher compared with baseline condition ( P ＜0 .05) . T he peak LD‐subendo and LD‐subepi ,RD‐subendo and RD‐subepi of LV in group B with the same condition were significant different ( all P ＜ 0 .05) . Conclusions On ultrasonic power 3 W ,LV LD‐subendo is decreased resulting to negative inotropic effect and RD‐subendo is increased to maintain the normal heart work .LV LD and RD on diagnostic ultrasound power irradiation 5 min , combined with contrast agent irradiation 5 min ,contrast agent 20 min conditions ,ultrasonic power 1 W and 2 W are not prominent changes .