Evaluation of distal turbulence intensity for the detection of both plaque ulceration and stenosis grade in the carotid bifurcation using clinical Doppler ultrasound

Objectives

To determine the interrelationship of stenosis grade and ulceration with distal turbulence intensity (TI) in the carotid bifurcation measured using conventional clinical Doppler ultrasound (DUS) in vitro, in order to establish the feasibility of TI as a diagnostic parameter for plaque ulceration.

Methods

DUS TI was evaluated in a matched set of ulcerated and smooth-walled carotid bifurcation phantoms with various stenosis severities (30, 50, 60 and 70 %), where the ulcerated models incorporated a type 3 ulceration.

Results

Post-stenotic TI was significantly elevated owing to ulceration in the mild and moderate stenoses (P?<?0.001). TI increased with stenosis severity in both the ulcerated and non-ulcerated series, with a statistically significant effect of increasing stenosis severity (P?<?0.001). Whereas TI in the mild and non-ulcerated moderate stenoses was less than 20.4?±?1.3 cm s^?1, TI in the ulcerated moderate and severe models was higher than 25.6 ±1.3 cm s^?1, indicating a potential diagnostic threshold.

Conclusion

We report a two-curve relationship of stenosis grade and ulceration to distal TI measured using clinical DUS in vitro. Clinical DUS measurement of distal TI may be a diagnostic approach to detecting ulceration in the mild and moderately stenosed carotid artery.

Key Points

? Patients with carotid artery plaque ulcerations are at higher risk of stroke. ? Clinical Doppler ultrasound is routinely used to detect carotid artery stenosis. ? Doppler ultrasound turbulence intensity can detect ulceration in realistic flow models. ? Turbulence intensity also increases with stenosis severity independent of ulceration. ? Doppler ultrasound should help in assessing both stenosis severity and ulceration.