Vascular_Ultrasound_Presentation (1).pptx

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.