Effects of different ultrasound power application on left ventricular myocardium 2-dimension strain in in vivo open-chest beagle canines / 中华超声影像学杂志

ABSTRACT

Objective To evaluate the left ventricular(LV)myocardial mechanical changes with contrast agent and different power irradiation in open-chest beagle canines.Methods The 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.The peak circumferential strain(CS),longitudinal strain(LS)and radial strain(RS)of LV myocardial wall were measured and analyzed using a dedicated Syngo velocity vector imaging(VVI)method.Results In group A,the peak CS and LS were increased significantly on diagnostic power irradiation,contrast agent irradiation 5 min and contrast agent 20 min(all P <0.05,respectively) compared with baseline condition;there was no significant difference of the peak RS on diagnostic power irradiation,contrast agent irradiation 5 min and contrast 20 min compared with baseline condition(P >0.05).In group B,the peak CS and LS were higher on power 1 W than on baseline condition(P <0.05), the peak RS was increased gradually on power 1 W than on baseline condition(P >0.05);the peak CS,LS, RS were lower on power 2 W than on baseline condition(P >0.05);the peak of CS,LS were lower on power 3 W than on baseline condition(P <0.05);the peak of RS was decreased gradually without significant changes between power 3 W on baseline condition(P >0.05).Conclusions These findings indicate potential positive inotropic effects with diagnostic ultrasound power irradiation 5 min,combined with contrast agent irradiation 5 min,contrast agent 20 min conditions,power 1 W and negative inotropic effects with power 3 W on LV myocardial CS,LS deformation.LV myofiber deformation reactions appear no significant differences on LV myocardial RS deformation in same disturbed setting.