Vascular ultrasound

1. VASCULAR ULTRASOUND
• Overview for MMed Radiology
• Prepared by: [Your Name]
• Department of Radiology

2. Introduction
• Vascular ultrasound uses high-frequency
sound waves to assess blood vessels.
• Evaluates arterial and venous structures,
blood flow, and hemodynamics.
• Includes Doppler techniques: Color, Power,
and Spectral Doppler.
• Commonly used for non-invasive assessment
of vascular diseases.

3. Basic Principles
• Sound reflection occurs at interfaces of
different acoustic impedance.
• Doppler Effect: frequency shift occurs when
sound reflects off moving red blood cells.
• The Doppler shift is proportional to velocity
and cosine of the angle of insonation.
• Angle correction: ideal Doppler angle ≤ 60°.

4. Types of Doppler Ultrasound
• 1. Color Doppler: displays mean flow velocity
and direction in color.
• 2. Power Doppler: sensitive to low flow,
independent of direction.
• 3. Spectral Doppler: provides quantitative
velocity data (waveform analysis).
• 4. Continuous-wave (CW) Doppler: measures
high velocities without depth info.
• 5. Pulsed-wave (PW) Doppler: allows depth
selection but limited by aliasing.

5. Equipment and Settings
• High-frequency linear transducer (5–12 MHz)
for superficial vessels.
• Curvilinear or phased array for deeper vessels.
• Adjust gain, PRF, and wall filter for optimal
flow visualization.
• Angle correction and sample gate placement
are essential for accurate velocity
measurement.

6. Vascular Ultrasound Applications
• Arterial System: carotid, peripheral arteries,
renal, mesenteric, aorta.
• Venous System: DVT evaluation, venous reflux.
• Transplant vessels: hepatic, renal grafts.
• Monitoring: graft patency, fistula function in
dialysis patients.

7. Carotid Artery Ultrasound
• Evaluates stenosis, plaque morphology,
occlusion.
• B-mode: wall thickening, plaque echogenicity.
• Color Doppler: flow turbulence and direction.
• Spectral Doppler: measure PSV for stenosis
grading.
• ICA/CCA PSV ratio helps quantify stenosis
severity.

8. Peripheral Arterial Ultrasound
• Used for PAD assessment.
• Examine femoral, popliteal, tibial arteries.
• Normal waveform: triphasic; abnormal:
monophasic/biphasic.
• Detects occlusion, stenosis, aneurysm, graft
patency.

9. Abdominal Aorta Ultrasound
• Screening for AAA.
• Normal diameter < 3 cm.
• Measure AP diameter in longitudinal and
transverse planes.
• Assess mural thrombus, dissection, or rupture.

10. Renal and Mesenteric Arteries
• Renal artery stenosis: elevated PSV >180 cm/s,
post-stenotic turbulence.
• Resistive Index (RI): (PSV – EDV)/PSV; normal
RI <0.7.
• Mesenteric ischemia: PSV >275 cm/s in SMA
indicates stenosis.

11. Venous Ultrasound (Lower Limb)
• Main indication: suspected DVT.
• B-mode: vein compressibility is key.
• Color Doppler: absence of flow = thrombosis.
• Augmentation test: squeeze distal limb —
normal increases flow.
• Spectral Doppler: spontaneous and phasic
flow patterns.

12. Venous Insufficiency / Varicose
Veins
• Evaluate for valvular incompetence.
• Reflux time >0.5 s indicates insufficiency.
• Mapping of saphenous system before
surgery/ablation.
• Color Doppler shows retrograde flow on
Valsalva or compression.

13. Upper Limb Vascular Ultrasound
• Used for thrombosis, dialysis access, trauma
evaluation.
• Assess subclavian, axillary, brachial, radial,
ulnar vessels.
• Check for fistula patency, flow volume,
anastomotic stenosis.

14. Common Vascular Pathologies
• Atherosclerosis and stenosis
• Aneurysms
• Thrombosis and embolism
• Dissections
• Vasculitis
• Venous insufficiency
• Post-surgical graft abnormalities

15. Advantages of Vascular Ultrasound
• Non-invasive and safe.
• Portable and repeatable.
• Real-time hemodynamic assessment.
• Cost-effective for screening and follow-up.

16. Limitations
• Operator-dependent.
• Limited visualization in obese patients or
overlying gas.
• Difficult in heavily calcified vessels.
• Aliasing and angle errors affect accuracy.

17. Safety and Artifacts
• Ultrasound is safe — no ionizing radiation.
• Common artifacts: aliasing, mirror image,
blooming, spectral broadening.
• Proper angle, PRF adjustment, and gain
control reduce artifacts.

18. Summary
• Combines B-mode, Color, and Doppler
techniques.
• Essential for diagnosing arterial and venous
pathologies.
• Requires understanding of hemodynamics and
waveform interpretation.
• Important for screening, diagnosis, and follow-
up.