Automated analysis of strain rate and strain: feasibility and clinical implications.
BACKGROUND
This study evaluated 3 new automated methods, based on a combination of speckle tracking and tissue Doppler, for the analysis of strain rate (SR) and strain. Feasibility and values for peak systolic strain rate (SR s ) and end-systolic strain (S es ) were assessed.


METHODS
Thirty patients with myocardial infarction and 30 normal subjects were examined. Customized software with automatic definition of segments was used for automated measurements. SR s and SR es were measured over each segment simultaneously and identified automatically. The study compared tissue Doppler-based SR and strain measurements without (method 1) and with segment tracking (method 2) to speckle tracking-based measurements (method 3). For tracking, speckle tracking and tissue Doppler were used in combination. Standard manual analysis was used as a reference.


RESULTS
The automated analysis (16 segments, 3 apical views) required 2 minutes; manual analysis took 11 minutes. Accuracy was compared in 56 segments (28 mid-infarcted and 28 normal) from 28 patients and was 93.9% for method 1, 93.8% for method 2, 95.8% for method 3, and 96.2% for the manual method. In the normal group, mean SR s (0.27 s -1 ) was less with method 3 than with the other methods ( P < .001).


CONCLUSIONS
Our findings indicate that automated analysis of SR and strain, with some manual adjustment, is feasible and quicker than manual analysis. Diagnostic accuracy was similar with all methods. SR s was lower in the speckle tracking-based method than in the Doppler-based methods.
Ingul
Charlotte Bjork
CB
Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Tronsheim, Norway. charlotte.b.ingul@ntnu.no
Torp
Hans
H
Aase
Svein Arne
SA
Berg
Sigrid
S
Stoylen
Asbjorn
A
Slordahl
Stig A
SA
D015150:Echocardiography, Doppler; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D012372:ROC Curve; D012680:Sensitivity and Specificity