An image-free ultrasound method to estimate artery wall thickness surrogate for screening

Carotid Intima Media Thickness (CIMT) is an established marker of cardiovascular risk with proven utility in early detection. However, conventional B-mode ultrasound imaging based measurement of CIMT is not amenable for deployment in large scale screening due to cost and expertise required to perform the test. We had developed and validated an image -free ultrasound technique for non-invasive, automated evaluation of arterial wall dynamics, called ARTSENS®, for use in vascular screening. Here we present a novel technique to evaluate a carotid artery wall thickness surrogate (CWTS) measure using ARTSENS®, utilizing a single-element 5 MHz ultrasound transducer. The method is based on real time analysis of ultrasound echoes obtained from the far-wall of the common carotid artery. Intelligent algorithms for automated identification of arterial walls, tracking of wall motion, and extraction of far wall structural echoes and measurement of a wall-thickness estimate were developed, and integrated into a prototype ARTSENS® device to enable real time measurement of wall thickness in-vivo. The performance of the system was evaluated using dynamic arterial flow phantoms and in-vivo studies on a set of 7 volunteers. The system could track changes in wall-thickness over a cardiac cycle in both phantoms as well as volunteers in real time. Accuracy of measurements was evaluated in comparison with a reference B-mode ultrasound imaging system. The CWTS measurements showed strong agreement with CIMT values measured with observed error 2.18% and 6.19% in phantom studies and in-vivo measurements respectively. CWTS measurements were also strongly related to CIMT measurements with a R2 value 0.86. While the CWTS is not a replacement for CIMT, but the results validate that it can be potentially used for mass screening purpose, since the measuring system is very cost-effective, easily portable, includes low signal processing overhead and can be used by any general practitioner with just minimal training.