Stenosis

Peak Systolic Velocity

ICA/CCA Ratio

Peak End Diastolic Velocity

Spectral Broadening

Morphology

0-15%

<125 cm/s

1:1

<40 cm/s

Minimal

Minimal

16-49%

<125 cm/s

<2:1

<40 cm/s

Mild

Moderate

50-80%

<225 cm/s

<3:1

40-100 cm/s

Moderate-Severe

Severe

80-90%

<325 cm/s

<4:1

>100 cm/s

Severe

Severe

>90%

>325 cm/s

>4:1

>120 cm/s

Severe

Severe