  We present a new method for measuring global longitudinal strain and global
longitudinal strain rate from 2D echocardiograms using a logarithmic-transform
correlation (LTC) method. In contrast to traditional echocardiography strain
analysis, our approach does not require cardiac chamber segmentation and
regularization. The algorithm was benchmarked against two conventional strain
analysis methods using synthetic left ventricle ultrasound images. Measurement
error was assessed as a function of contrast-to-noise ratio (CNR) using mean
absolute error and root-mean-square error and showed better agreement to the
ground truth for strain($R^2$ = 0.91) and strain rate($R^2$ = 0.85) as compared
to conventional algorithms (strain($R^2$ = 0.7), strain rate($R^2$ = 0.7)).
Also, our method was unaffected by CNR. A 200% increase in strain measurement
accuracy was observed compared to the conventional algorithms. Subsequently, we
tested the method using a 54-subject clinical cohort (20 subjects diseased with
cardiomyopathy, 34 healthy controls). Our method distinguished between normal
and abnormal left ventricular function with an AUC = 0.85, a 10% improvement
over the conventional GLS algorithms.
