Direct estimation of global longitudinal strain from echocardiograms using a logarithm-scaled Fourier magnitude correlation
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.