Vascular Ultrasound

Question	Answer
Fluid Dynamics and Haemodynamics	Fluid Dynamics: ideal fluid + long uniform pipe Haemodynamics: blood + vascular system
Volume Flow Rate	Volume flow rate = area x average velocity Velocity stays the same only the flow rate and area change (divided by the amount of vessels) Aorta: velocity of 30cm/s
Idea Velocity Profile	Parabolic- this is unlikely, due to geometrical factors, varying diameters, bifurcations and curvature
Image: gradual_diameter_changes (image/jpg)	Gradual Diameter Changes (more likely turbulent flow in the elongated profile)
Image: sudden_diameter_changes (image/jpg)	Turbulent flow and even reverse flow is occurring due to the sudden increase in diameter
Image: bifurcations (image/jpg)	Velocity profile due to bifurcations
Image: vessel_curvature (image/jpg)	Vessel curvature
General Trends	-Diameter and velocity decreases through the arterial system -velocity profile: plug flow + variation with vessel geometry Poiseuille's equation: flow rate is controlled by vessel radius -Critical velocity and turbulence -Critical stenosis: reduced diameter and turbulance (increase in resistance and reduced flow rate)
Pulsatile Flow	Each artery has varying degrees of diastolic flow. Reverse flow during diastole
Venous Flow	Low pressure and velocities with more continuous flow. No turbulence or disturbed flow with parabolic velocity profiles.
Vascular Sonography	B-mode- anatomical info Colour Doppler- overall dynamics of blood flow Power Doppler- vascular anatomy Spectral Doppler- quantitative haemodynamic assessment
Scanning Technique	-Assess entire artery in length -use B mode assessment, then colour doppler and spectral doppler -use both planes.
Sonographic Appearance	-Lumen is anechoic -lumen to intima is an echogenic line -tunica media is anechoic -Media to adventitia is the second echogenic line Arteries exhibit pulsatile flow and are resistant to compression
Image: vessel (image/jpg)	Lumen, intima, media and adventitia
Carotid Indication	TIA, carotid bruit, pulsatile neck mass, pre-op for surgery and amaurosis fugax
Carotid U/S	Linear transducer (6-12MHz) assess CCA from origin and the carotid bifurcation. Vertebral arteries for the direction of flow.
Internal and External Carotid Artery Waveforms	Internal- high diastolic flow (low resistance External - low diastolic flow ( high resistance)
Arterial Occlusion	-absence of doppler signal -open sample volume across the vessel and reduced PRF to detect low flow
ICA Occlusion	-severe stenosis requires surgical treatment -occlusion is not treated surgically *Identified by: absence of ICA signal and reduced velocities and high resistance signal in the common carotid artery.
Vertebral Artery	-normal waveform is low resistance -determine direction of flow -Retrograde flow indicate subclavian pathology
Lower Limb Ultrasound Indications	Claudication, absent pulses, ischaemic ulcers, graft monitoring
Lower Limb Method	-Curved transducer for abdomen -liner for legs -Assess from aorta to ankle
Venous Anatomy	-Deep veins -superficial veins -communicating or perforating veins.
Common Indications	DVT, venous insufficiency and vein mapping
Venous Anatomy	Have low pressure and resistance Contain valves to stop reverse flow Are compressible
Appearance	Vein walls are imperceptible Lumen is anechoic
Augmentation and Compression	Augmentation- to squeeze a limb inferior to where you are scanning Compression- to manually compress a vein

Next up

Description

Resource summary

Similar

	Created by johanna_hillbrick almost 10 years ago