Peak systolic velocity ratios arterial duplex

Ratio PSV* at stenotic segment/normal segment	Degree of stenosis
1.5-2.0	30-49 percent
2.0-4.0	50-75 percent
>4.0	>75 percent

Measuring the degree of stenosis using duplex ultrasound.

* PSV: peak systolic velocity.

Courtesy of the Division of Vascular Surgery at OHSU.

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