اندازه گيري اتو ماتيك آهنگ تغييرات شعاعي ديواره شريان كاروتيد با استفاده از تصاوير متوالي فراصوتي ؛ الگوريتم حدااكثر گراديان

Automatic measurement of instantaneous changes in the walls of carotid artery with sequential ultrasound images

Introduction: This study presents a computerized analyzing method for detection of instantaneous changes of far and near walls of the common carotid artery in sequential ultrasound images by applying the maximum gradient algorithm. Maximum gradient was modified and some characteristics were added from the dynamic programming algorithm for our applications. Methods: The algorithm was evaluated on the common carotid artery of 10 healthy volunteers. Local measurements of vessel intensity, intensity gradient and boundary continuity are extracted for all of the sequential ultrasonic frames throughout three cycles. We extracted the instantaneous changes of far and near arterial walls and hence the lumen diameter. The manual measurements were applied and compared for validation of the automatic method. Peak systolic, end diastolic and mean diameters extracted by the automated method were compared with the same parameters measured by the manual method throughout three cycles. Results: There was no significant difference between automated and manual methods (p>0.05) with paired t-test analysis. In the verification study, correlation between automated and manual methods was excellent (R2 = 0.85, p<0.05) with a negligible bias (0.003 mm) as determined by Bland Altman analysis. Conclusion: It is concluded that computerized analyzing method can automatically detect the instantaneous changes of the arterial walls in sequential B-mode images.