A novel feature-tracking echocardiographic method for the quantitation of regional myocardial function: validation in an animal model of ischemia-reperfusion.
OBJECTIVE
The aim of this study was to validate a novel, angle-independent, feature-tracking method for the echocardiographic quantitation of regional function.


BACKGROUND
A new echocardiographic method, Velocity Vector Imaging (VVI) (syngo Velocity Vector Imaging technology, Siemens Medical Solutions, Ultrasound Division, Mountain View, California), has been introduced, based on feature tracking-incorporating speckle and endocardial border tracking, that allows the quantitation of endocardial strain, strain rate (SR), and velocity.


METHODS
Seven dogs were studied during baseline, and various interventions causing alterations in regional function: dobutamine, 5-min coronary occlusion with reperfusion up to 1 h, followed by dobutamine and esmolol infusions. Echocardiographic images were acquired from short- and long-axis views of the left ventricle. Segment-length sonomicrometry crystals were used as the reference method.


RESULTS
Changes in systolic strain in ischemic segments were tracked well with VVI during the different states of regional function. There was a good correlation between circumferential and longitudinal systolic strain by VVI and sonomicrometry (r = 0.88 and r = 0.83, respectively, p < 0.001). Strain measurements in the nonischemic basal segments also demonstrated a significant correlation between the 2 methods (r = 0.65, p < 0.001). Similarly, a significant relation was observed for circumferential and longitudinal SR between the 2 methods (r = 0.94, p < 0.001 and r = 0.90, p < 0.001, respectively). The endocardial velocity relation to changes in strain by sonomicrometry was weaker owing to significant cardiac translation.


CONCLUSIONS
Velocity Vector Imaging, a new feature-tracking method, can accurately assess regional myocardial function at the endocardial level and is a promising clinical tool for the simultaneous quantification of regional and global myocardial function.
Pirat
Bahar
B
Methodist DeBakey Heart Center Echocardiography Laboratory and Baylor College of Medicine, Division of Cardiology, Houston, Texas 77030, USA.
Khoury
Dirar S
DS
Hartley
Craig J
CJ
Tiller
Les
L
Rao
Liyun
L
Schulz
Daryl G
DG
Nagueh
Sherif F
SF
Zoghbi
William A
WA
D000818:Animals; D001783:Blood Flow Velocity; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology*; D004280:Dobutamine; D004285:Dogs; D004699:Endocardium; D005260:Female; D008297:Male; D023421:Models, Animal; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging / Q000503:physiopathology*; D015425:Myocardial Reperfusion; D009206:Myocardium; D011412:Propanolamines; D013599:Systole; D014463:Ultrasonography
D011412:Propanolamines; D004280:Dobutamine; C036604:esmolol