Enhancement of contrast echocardiography by image variability analysis

Background: Although there have been recent advances in echocardiography, m any studies remain suboptimal due to poor image quality and unclear blood-m yocardium border. We developed a novel image processing technique, cardiac variability imaging (CVI), based on the variance of pixel intensity values during passage of ultrasound microbubble contrast into the left ventricle c hamber, with the aim of enhancing endocardial border delineation and image quality. Methods and Results: CVI analysis was performed on simulated data to test a nd verify the mechanism of image enhancement. Then CVI analysis was applied to echocardiographic images obtained in two different clinical studies, an d still images were interpreted by expert reviewers. In the first study (N = 15), using contrast agent EchoGen, the number of observable wall segments in end-diastolic images, for example, was significantly increased by CVI ( 4.93) as compared to precontrast (3.28) and contrast images (3.36), P < 0.0 01 for both comparisons to CVI. In the second study (N = 8), using contrast agent Optison, interobserver variability of manually traced end-diastolic volumes was significantly decreased using CVI (22.3 ml) as compared to prec ontrast (63.4) and contrast images (49.0), P < 0.01 for both comparisons to CVI. Conclusion: CVI can substantially enhance endocardial border delineation an d improve echocardiographic image quality and image interpretation.