Kelly, I know that and we also determine flow velocities but often the stenosis can be underestimated due to arrhytmias, subocclusive stenosis, hypertension or contralateral stenosis. I think that except for calcified plaques, percent stenosis is useful, but correlation with angiography is difficult. Carlos ---------- De: Kelly Estes[SMTP:[log in to unmask]] Enviado: viernes 3 de septiembre de 1999 23:28 Para: [log in to unmask] Asunto: Re: Carotid stenosis. In a message dated 09/03/1999 5:21:35 PM Eastern Daylight Time, [log in to unmask] writes: << we measure stenosis by ultrasound comparing the diameter of the lumen with the diameter of the vessel at the point of maximum stenosis (real stenosis), but correlation with the results of arteriography is sometimes poor because they compare the diameter of the lumen with the distal diameter of the carotid. >> Carlos, Most vascular labs (I hope) are not measuring off of the 2D image for percent stenosis, rather they are doing velocity measurements with angle corrected Doppler. This is the most accurate way to determine percent stenosis with ultrasound technology. There are many published charts with criteria available. I hope this helps....... Kelly Estes RT(R), RDMS, RDCS, RVT