Changes in Internal Carotid Artery Doppler Velocity Measurements With Different Angles of Insonation: A Pilot Study.
Publication Title
Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine
Document Type
Article
Publication Date
12-4-2020
Keywords
Doppler; angle; consistency; duplex; variance; velocity
Abstract
OBJECTIVES: Doppler velocity measurements are fundamental diagnostic criteria for vascular ultrasound examinations. Insonation angles are kept to 60° or less to minimize error. The purpose of this study was to assess variance of Doppler-detected peak systolic velocity (PSV) measurements in the internal carotid arteries at different angles (45°, 50°, 55°, and 60°) with different beam steering.
METHODS: The PSV was recorded from the right and left internal carotid arteries in 22 asymptomatic volunteers with straight vessels (total of 44 vessels). A standardized approach was used for recording velocities with the Doppler cursor center steered and steered 15° from right to left. An analysis of variance was performed.
RESULTS: The PSV varied significantly with the 4 different angles of insonation (P < .01). The maximum variation between 45° and 60° angles within a single vessel was 29 cm/s. The average variation over the 4 angles was 14 ± 6 cm/s. Relative to the calculated mean velocity for all patients, the standard deviation for the PSV at 60° was nearly twice that recorded at 50° (7.9 versus 3.9). The best correlation of the calculated mean velocity for all patients existed between the angles of 45° and 50° [r(36) = 0.92; P < .001 for center-steered data; and r(40) = 0.96; P < .001 for right-steered data].
CONCLUSIONS: These results indicate a statistically significant difference in the PSV measurements taken at varying Doppler angles. The greatest mean, variance, and lowest correlations all result when using 60°. The findings support the need for consistent ultrasound techniques and suggest that further study is warranted regarding the optimal Doppler angle for velocity measurements.
Area of Special Interest
Cardiovascular (Heart)
Specialty/Research Institute
Cardiology
