Vascular Ultrasound

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Fundamentals of Vascular Ultrasound. Looking at the basics of carotid, lower extremity arterial, renal, celiac, SMA studies, as well as touching on venous insufficiency. Part I of series.


<ul><li>1.steve henao md new mexico heart institute</li></ul> <p>2. Carotid 3. Carotid disease accounts for 25% of all strokesdetection by physical exam is poorstroke is the result of embolizationlesions are typically at the posterolateral wall of theinternal carotid artery 4. CAROTID ULTRASOUND The most common clinical application is for the detection of proximal ICA atherosclerotic plaque and estimation of stenosis severity. The extent of ICA bifurcation diameter reduction predicts the risk for stroke and thus assists clinicians in identifying patients who may benefit from carotid intervention (endarterectomy, stent angioplasty) based on clinical trial results 5. Scanning the ICA grayscale, color Doppler and Pulse-wave Doppler proximal, middle, and distal portions &gt;50% stenosis of the proximal ICA renders flow turbulent in the distal ICA severe stenosis yields parvus et tardus waveforms 6. proxmial ICA stenosis severity is established on the baisis of : GRAYSCALE APPEARANCE PEAK SYSTOLIC VELOCITY OF THE ICA END DIASTOLIC VELOCITY OF THE ICA PEAK SYSTOLIC VELOCITY OF THE COMMON CAROTID ARTERY velocity ratios 7. Grayscale imaging is performed to localize and characterize plaque severity as:less than 50%greater than or equal to 50%occlusion 8. Color Doppler flow mapping is useful to define the lumenbecause hypoechoic plaque and restenosis material may be inapparent by regular grayscale 9. assessment of stenosis angiography is the traditional gold standard ultrasound has developed steadily with sufficiently reliable preoperative results 10. assessment of stenosis there are MANY differences in the carotid reference standard to establish percent stenosis 11. stenosis standards 12. doppler ultrasound criteria for diagnosis of internal carotid artery stenosis(2003) 13. validating the consensus document (2011) 14. characteristic characteristic The ROC curve was first developed by electrical engineers and radar engineers during World War II for detecting enemy objects in battlefields and was soon introduced to psychology to account for perceptual detection of stimuli. ROC analysis since then has been used in medicine, radiology, biometrics, and other areas for many decades and is increasingly used in machine learning and data mining research. 15. Fig 1Source: Journal of Vascular Surgery 2011; 53:53-60 (DOI:10.1016/j.jvs.2010.07.045 ) Copyright 2011 Society for Vascular Surgery Terms and Conditions 16. Fig 2Source: Journal of Vascular Surgery 2011; 53:53-60 (DOI:10.1016/j.jvs.2010.07.045 ) Copyright 2011 Society for Vascular Surgery Terms and Conditions 17. Fig 3Source: Journal of Vascular Surgery 2011; 53:53-60 (DOI:10.1016/j.jvs.2010.07.045 ) Copyright 2011 Society for Vascular Surgery Terms and Conditions 18. analysis the parameter with the highest Pearson correlate to angiography was the PSV (0.813), in contrast to both EDV (0.7) and ICA/CCA PSV ratios (0.57, P &lt; .0001) A PSV of &gt;230 cm/s was the most sensitive in the diagnosis of 70% to 99% stenosis, and adding other parameters (EDV or ratios) did not improve the overall accuracy 19. analysis Using a PSV of &gt;230 cm/s with an EDV of &gt;100 cm/s or a systolic ratio of &gt;4 would improve the PPV to 99% and the specificity to 97% 20. analysis the ICA/CCA PSV ratio and the ICA EDV are useful parameters when the ICA PSV may not be representative of the extent of carotid disease because of technical or clinical factors: presence of contralateral high-grade stenosis or occlusiondiscrepancy between visual assessment of the carotid plaque and the ICA PSVelevated CCA velocity, low cardiac output, or hyperdynamic cardiac state 21. analysis patients with low cardiac output would have a low ICA PSV, which is disproportionate when compared with the ICA/CCA PSV ratio. In these situations, the clinician must rely on the presence of the plaque and perhaps the ICA/CCA ratio rather than the absolute ICA PSV 22. carotid endarterectomy the PSV threshold of 230 cm/s for detecting 70% stenosis can be used before CEA for symptomatic patients since surgery has been proven to be beneficial, even for 50% symptomatic stenosis A higher PSV (eg, 280 cm/s), which has a PPV of 97%, or a PSV of &gt;230 cm/s with an EDV of &gt;100 cm/s, or a systolic ratio of &gt;4 (PPV of 99%) may be considered in asymptomatic patients 23. POST-CAROTID STENTING CRITERIAInterpretation of high-grade (&gt;75% to 80%) in-stent stenosis should be based on elevation of EDV beyond 125 to 140 cm/second 24. SUMMARY(2014) The variability in carotid stenosis interpretation across accredited facilities undermines the usefulness of this important diagnostic modality. The IAC Vascular Testing Board of Directors feels that more standardization of carotid duplex ultrasound diagnostic criteria will address these concerns and will enhance the accuracy, reproducibility, portability and value of duplex sonography for the diagnosis of carotid disease. 25. lower extremity arterial arterial 26. Indications for Duplex Arterial Testing Duplex Arterial Testing Acute limb ischemia as a result of arterial thrombosis caused by atherosclerosis, thromboembolism, trauma, or peripheral aneurysmChronic arterial occlusion/stenosis with intermittent claudication or an abnormal ( 3.5 cm, especially if mural thrombus is imaged 41. AORTA Reporting should include: morphology (saccular, fusiform) extent presence of mural thrombus or dissection outside wall-to-wall diameter 42. AORTA typical growth rate for AAA= 3 to 4 mm/year 43. RENAL artery artery 44. Renal Artery Duplex HTN and sudden deterioration in renal function are the most common indicationsatherosclerosis 95%1 to 6% of HTN patients, but most common cause of HTN in pts &gt;50men affected 2x womenarterial fibrodysplasia 5% 45. RAR interpretation of renal artery stenosis is based on the maximum PSV obtained from the aorta above the renal arteries (at the level of the SMA) and the renal artery itself 46. renal interpretation &amp; reporting &amp; reporting Normal Study:PSV: 80 20 cm/secondRenal-to-aortic PSV ratio (RAR): less than RAR 3.5Normal waveform: biphasicNo focal velocity increaseLow resistance waveform (RI 0.8 ABNORMAL 52. CELIAC SMA IMA IMA 53. Celiac NORMAL PSV = 90 to 110 cm/second low-resistance flow pattern no plaque visualized laminar and forward flow throughout diastole 54. celiac &lt; 70% Stenosis PSV: &lt; 200 cm/second EDV: &lt; 55 cm/ second resistive index similar to that of the ICA 55. celiac&gt; 70% stenosis PSV &gt; 200 cm/second EDV &gt; 55 cm/ second with retrograde hepatic artery flow 56. SMA NORMAL PSV: 95 to 150 cm/second high-resistance flow pattern in fasting state EDV &gt; 0 after a meal no plaque visualized laminar and forward flow throughout diastole 57. SMA &lt; 70% Stenosis PSV 70% Stenosis PSV &gt; 300 cm/second EDV &gt; 45 cm/ second with loss of diastolic flow reversal mesenteric - aorta ratio &gt; 3 velocity spectra change with test meal increase in PSV at sites of stenosis with damping of the distal waveform 59. LOWER EXTREMITY VENOUS VENOUS 60. VENOUS REFLUX a prospective study has demonstrated that the acceptable physiologic flow reversal is different for different veins JeanneretC,LabsKH,AschwandenM,et al:Physiological reflux and venous diameter change in the proximal lower limb veins during a standardised Valsalva manoeuvre.Eur J Vasc Endovasc Surg1999;17:398-403. 61. VENUS REFLUXthe theory supporting this concept is that larger veins have fewer valves the expected time for the valve leaflets to come together is longer than that for smaller, shorter veins 62. venous refluxREFLUX = 1000 milliseconds common femoral femoral popliteal 63. venous reflux REFLUX = 500 milliseconds superficial deep femoral deep calf axial muscular veins 64. venous refluxREFLUX = 350 milliseconds perforating veins 65. steve henao md new mexico heart institute </p>


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