Ultrasound. You need a carotid doppler.
Medical management. A "bruit" is noise transmitted from turbulent flow. The most common cause of a bruit is atherosclerosis either in the chest arteries or neck arteries. A fair number of healthy people can have a benign bruit due to turbulent flow. A few tests - carotid ultrasound, ankle brachial index can establish if there is atherosclerosis. If you do have atherosclerosis, medical management, no smoking is key.
See your doctor. This may be early sign of carotid disease. As the carotid narrow blood squeeze through a tight area faster resulting in a bruit that we hear.