What is the North American method for assessing carotid stenosis?
The North American method for assessing carotid stenosis is a method of measuring the minimal residual lumen at the level of the stenotic lesion compared with the diameter of the more distal internal carotid artery. This method uses the formula: stenosis=(1 N/D) 100%, where N is the diameter at point of maximum stenosis and D is the diameter of the arterial segment distal to the stenosis where the arterial walls first become parallel. It is in contrast to the European method, which estimates stenosis of the internal carotid bulb.