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. Author manuscript; available in PMC: 2016 Mar 1.
Published in final edited form as: Ultrasound Med Biol. 2015 Jan 22;41(3):685–697. doi: 10.1016/j.ultrasmedbio.2014.09.016

Table 1. UNC stenosis grading scale.

Class Vel. Systolic (cm/sec) Vel. Diastolic (cm/sec) Category
1 < 160 < 80 0-39%
2 > 160 < 80 40-59%
3 > 160 80-109 Possibly > 60%
4 > 160 > 110 60-99%
5 0 0 Occluded
6* See comment See comment See comment
*

This grade is only given in special circumstances where further comments by the sonographer are necessary.