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Table 1 How to adjust the Doppler settings in large vessel vasculitis

From: Settings and artefacts relevant for Doppler ultrasound in large vessel vasculitis

Flow type The flow is fast and in vasculitis direction and velocity are important for diagnosis
PRF and wall filters Different PRF for different vessels:
 Temporal and facial arteries, PRF range = 2–3.5 kHz
 Carotis, subclavian and axillary arteries, PRF range = 3–4 kHz
 Vertebral and occipital arteries, PRF range = 0.7–1.5 kHz
High PRF ensures display of correct flow direction and velocity
Wall filters are linked controls and with a high PRF, the wall filter will also be high to eliminate motion artefacts from moving arterial walls
Choice of Doppler CD as it displays the mean blood velocity
Spectral Doppler for indicating correct insonation angle and for calculating the correct velocity of the flow
Doppler frequency Optimal frequency varies according to the location of the vessel
Higher for temporal arteries lower for the larger arteries because of penetration
Gain Gain should be adjusted according to noise level for both CD and spectral Doppler but with a minimum of blooming
Colour priority If adjustable, then it should be kept high to ensure Doppler filling in the vessel
Focus At the level of region of interest to ensure optimal Doppler sensitivity