Walif Chbeir Radiology Notes
December 14, 2016
Peripheral Artery Stenosis Grading by Doppler Ultrasound
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* The Peak Systolic Velocity across the stenosis and the Velocity Ratio are the best predictors of peripheral arterial stenosis severity when expressed as % Diameter Reduction.
The Velocity Ratio is the ratio of the PSV at the stenosis compared with the velocity 1–2 cm upstream in a non-diseased segment.
* Normal arteriel caliber
• Triphasic waveform.
• No spectral broadening .
• Normal PSV < 150 cm/sec.
• Velocity Ratio (VR) < 1,5
* 1-19% diameter reduction
• Triphasic waveform with
• Minimal spectral broadening.
• PSV increase < 30% relative to adjacent proximal segment (VR < 1,5)
• Proximal and distal waveforms remain normal* Less than 50% ( 20- 49 %)
• Plaque visualized on grayscale imaging
• Triphasic/biphasic waveforms. Triphasic waveform usually maintained, but reverse flow diminished
. Spectral broadening prominent: Filling in of clear area under the systolic peak
. PSV 150-200.
• 30% to 100% increase in PSV compared with that immediately proximal to the site of
stenosis. VR: 1,5-2
. Proximal and distal waveforms remain normal
* 50 % to 75 % diameter reduction
– Prestenotic segment: Normal
– Intrastenotic segment
. Plaque visualized
. Color flow representation of narrowed flow Channel
. ± Monophasic waveform, loss of reverse flow ( variable) and forward flow throughout cardiac cycle ( si jusqu a 99%).
. Elevated PSV >180 cm/s (200-300).
. More than 100% increase in peak systolic flow velocity compared with that immediately proximal to the site of stenosis. VR 2-4
– Partial post-stenotic turbulence: Systolic spectral broadening
– Distal waveform: Monophasic waveform , Reduced PSV
* 76-99% stenosis– Prestenotic segment: Increased pulsatility
– Intrastenotic segment:
. the real time color Doppler flow will appear as a whitened, color desaturated “flow jet”
. with mosaic color flow extending for several vessels diameters downstream, corresponding to post-stenotic turbulence
. monophasic waveforms
. PSV > 300. EDV > 40. Increased PSV > 4x normal: VR = 4.
– Poststenotic segment: Marked turbulence with Extensive spectral broadening & Simultaneous forward and retrograde velocity spectra during systole & damped waveforms with high-grade obstruction. The spectral broadening (turbulence) may be seen throughout the spectrum if the stenosis is close to the point of measurement; as the distance from the stenosis increases, the spectral broadening is seen in the postsystolic deceleration phase only.
– Distal Waveform: Damped, Monophasic, Reduced.
* As stenosis severity increases to >90% DR, the volume flow through the stenosis trends toward zero, which can produce
. a PSV at the stenosis in a minimally elevated range (100 to 200 cm/s) and
. low velocity (<10 cm/s) “trickle” flow downstream.
– Occlusion Segment:
. No flow (Absence of color and spectral Doppler signals).
. Intraluminal echoes observed throughout vessel
– Preocclusive thump may be present just proximal to occlusion
– Distal waveform is damped, monophasic with reduced PSV.
• Post Occlusion Reconstitution:. Resumption of flow visualized by color Doppler
. Spectral Doppler flow pattern usually contains both forward and reverse flow
elements (influenced by reentry vessel flow)
– Lengh of occlusion estimated based on distance from exit and re-entry collaterals.
– Some patients will show extensive diffuse disease along the superficial femoral artery but do not show any specific, localised stenoses. This appearance may be severe enough to
produce a significant pressure drop along the vessel, thereby reducing limb perfusion.
– Patients may have several stenoses along the length of the vessel, each of which is not haemodynamically significant but the effects of these are additive, so that there is still a significant drop in perfusion pressure distal to the affected segment.
– The presence of serial stenoses can affect the estimation of the degree of a distal stenosis and a significant proximal stenosis or occlusion will result in a drop in perfusion pressure and velocity which makes application of the PSV and VR problematical.
– Otherwise, the use of velocity ratios in multiple stenoses is somewhat controversial.
Energy Doppler and echo-enhancing agents may allow an estimate of severity of the distal stenosis but if there is clinical doubt, other imaging (CTA, MRA, DSA) should be considered.
1– Kelley D. Hodgkiss-Harlowa, and Dennis F. Bandyk, Interpretation of arterial duplex testing of lower extremity arteries and interventions, S E M I N A R S I N V A S C U L A R S U R G E R Y 2 6 ( 2 0 1 4 ) 9 5 – 1 0
2- Simon S. M. Ho, Arterial Occlusive Disease, Peripheral, STATdx ( Ultrasound > Diagnosis > Vascular > Extremities).
3- T. Gregory Walker, Femoropopliteal Artery Occlusive Disease, STATdx (Vasculature > Diagnosis > Peripheral Vasculature > Lower Extremity Vasculature ) . https://my.statdx.com/document/femoropopliteal-artery-occlusive-d-/80f5f5fc-1be3-4765-9aa8- bd8c37a1cc84?searchTerm=Femoropopliteal%20Artery%20Occlusive%20Disease.4- Stuart J. Hutchison & Katherine C. Holmes, Lower Extremity Arterial Disease in PRINCIPLES of VASCULAR and INTRAVASCULAR ULTRASOUND, Chapter 5, p 99, ISBN 978-1-4377-0404-4, © 2012 by Saunders, an imprint of Elsevier Inc.
5- Paul L. Allan, The Peripheral Arteries, in Clinical Doppler Ultrasound, Third Edition, Myron A. Pozniak – Paul
L. Allan, Chapter 4, p. 82 , © 2014, Elsevier, ISBN: 9780702050152, e-book ISBN : 9780702055379.
6- Cossman et al. Comparison of contrast arteriography to arterial mapping with color-flow duplex imaging in the lower extremities. J Vasc Surg . 1989; 10:522–529.