Automatic Measurement of the Carotid Blood Flow for Wearable Sensors: A Pilot Study

The assessment of the velocity of blood flowing in the carotid, in modern clinical practice, represents an important exam performed both in emergency situations and as part of scheduled screenings. It is typically performed by an expert sonographer who operates a complex and costly clinical echograph. Unfortunately, in developing countries, rural areas, but even in crowded modern cities, the access to this exam can be limited by the lack of suitable personnel and ultrasound equipment. The recent availability of low-cost, hand-held devices contributes to solve part of the problem, but a wide access to the exam is still hampered by the lack of expert sonographers. In this work, an automated procedure is presented with the hope that in a near future it can be integrated in a low-cost, handheld instruments suitable also for self-measurement, like today is for example the finger oximeter. The operator should only place the probe on the neck, transversally with respect to the common tract of the carotid. The system, in real-time, automatically locates the vessel lumen, places the sample volume, and performs an angle-corrected velocity measurement of the common carotid artery peak velocity. In this study the method was implemented for test on the ULA-OP 256 scanner. Experiments on flow phantoms and volunteers shown a performance in sample volume placement similar to those achieved by expert operators, and an accuracy and repeatability of 3.2% and 4.5%, respectively.