Bosch, J.G.

Quantitative Analysis of Ultrasound Contrast Flow Behavior in Carotid Plaque Neovasculature (Article)

2012-10-11T00:00:00Z

Intraplaque neovascularization is considered as an important indication for plaque vulnerability. We propose a semiautomatic algorithm for quantification of neovasculature, thus, enabling assessment of plaque vulnerability. The algorithm detects and tracks contrast spots using multidimensional dynamic programming. Classification of contrast tracks into blood vessels and artifacts was performed. The results were compared with manual tracking, visual classification and maximal intensity projection. In 28 plaques, 97% of the contrast spots were detected. In 89% of the objects, the automatic tracking determined the contrast motion with an average distance of less than 0.5 mm from the manual marking. Furthermore, 75% were correctly classified into artifacts and vessels. The automated neovascularization grading agreed within 1 grade with visual analysis in 91% of the cases, which was comparable to the interobserver variability of visual grading. These results show that the method can successfully quantify features that are linked to vulnerability of the carotid plaque.

Automated Tracking of the Mitral Valve Annulus Motion in Apical Echocardiographic Images Using Multidimensional Dynamic Programming (Article)

2007-09-01T00:00:00Z

We developed a semiautomatic method for tracking the mitral valve annulus (MVA) in echocardiographic images, in particular, tracking the septal and the lateral mitral valve hinge points. The algorithm is based on multidimensional dynamic programming combined with apodized block matching. The method was tested on single-beat apical four chamber image sequences of 20 patients with acute myocardial infarction. The automated tracking results were evaluated by comparing them with the average manual tracking results of two experts. The mitral valve hinge point displacements and the total mitral excursions obtained by the automatic technique agreed well with those obtained manually and outperformed two commonly used tracking methods (forward tracking and minimum tracking). In conclusion, this novel semiautomatic tracking method is clinically valuable and capable of tracking the MVA motion within the limits of interobserver variability. The technique is robust, even in low frame rate, redigitized VCR images of clinical quality. (E-mail: S.T.Nevo@Student.TUDelft.NL).

Quantification of Left Ventricular Volumes and Function in Patients with Cardiomyopathies by Real-time Three-dimensional Echocardiography: A Head-to-Head Comparison Between Two Different Semiautomated Endocardial Border Detection Algorithms (Article)

2007-09-01T00:00:00Z

Objective: We evaluated two different commercially available real-time 3-dimensional echocardiographic semiautomated border detection algorithms for left ventricular (LV) volume analysis in patients with cardiomyopathy and distorted LV geometry. Methods: A total of 53 patients in sinus rhythm with various types of cardiomyopathy (mean age 56 ± 11 years, 28 men) and adequate 2-dimensional image quality were included. The real-time 3-dimensional echocardiographic multiplane interpolation (MI) and full volume reconstruction (FVR) methods were used for LV volume analysis. Magnetic resonance imaging was used as the reference method. Results: A strong correlation (R2> 0.95) was found for all LV volume and ejection fraction measurements by either real-time 3-dimensional echocardiographic method. Analysis time was shorter with the FVR method (6 ± 2 vs 15 ± 4 minutes, P < .01) as compared with the MI method. Bland-Altman analysis showed greater underestimation of end-diastolic and end-systolic volumes by MI compared with FVR. For the MI method a bias of -24.0 mL (-15.0% of the mean) for end-diastolic volume and -11.3 mL (-18.0% of the mean) for end-systolic volume was found. For FVR analysis these values were -9.9 mL (-6.0% of the mean) and -5.0 mL (-9.0% of the mean), respectively. Ejection fraction was similar for the MI and FVR method with a mean difference compared with magnetic resonance imaging of 0.6 (1.0%) and 0.8 (1.3%), respectively. Conclusion: In patients with cardiomyopathy, distorted LV geometry, and good 2-dimensional image quality, the FVR method is faster and more accurate than the MI method in assessment of LV volumes.