In Vitro Validation of Color Velocity Imaging and Spectral Doppler for Velocity Determination

Abstract

Color velocity imaging (CVI) is a new non-Doppler ultrasound technique for vascular color flow imaging. Using information contained in the two-dimensional B-mode, gray-scale image to determine velocity, CVI offers potential advantages over Doppler color flow imaging methods. In order to be used clinically, velocity determination with CVI must be validated by other current methods. A Doppler string phantom was studied with a Philips CVI ultrasound system. Velocity measurements were obtained by both CVI and duplex Doppler spectral analysis for constant string speeds from 10 to 200 cm/sec, at intervals of 10 cm/sec. Twenty separate estimates were obtained with each method, at each string speed. Linear regression assessed the relationship between estimated and actual string velocities, with CVI and spectral Doppler analysis yielding highly valid results (CVI = -0.713 + 1.000997 x phantom; r 2 = 0.9979). At all string speeds tested, the averaged estimated and the actual velocities for both methods were within the 95% confidence estimates. The range for the CVI 95% confidence limits from the regression line varied from +/-1.07 cm/sec at the lowest speed of 10 cm/sec (11.6%) to +/-7.72 cm/sec at 200 cm/sec (3.87%). Based on in vitro testing, CVI is as accurate as Doppler spectral analysis for the estimation of flow velocity.

Ultrasonic Quantitative Flow Volumetry of the Carotid Arteries: Initial Experience with a Color Flow M-Mode System

“…The accuracy of the flow velocity information of the color flow imaging system we used was tested in vitro [5] and in vivo [6], These data showed an excellent correla tion of actual flow velocity and indicated flow velocities as tested on a string phantom. Compared to other color duplex systems, the velocity determination on the system we used (Philips P700, Philips Ultrasound, Santa Ana, Calif., USA) is not based on the Doppler (frequencydomain) but on a time-domain principle, which deter mines flow velocities independently of the transmitted frequencies of the operating system [7], This Philips CVI (color velocity imaging) system provides a special soft ware for quantification of flow volume (CVI-Q, color velocity imaging quantify).…”

Cerebral Blood Flow Measurement by Color Velocity Imaging in Radiation-Induced Carotid Stenosis

“…Phantom and human studies have shown that both CVI and SDI are accurate for assessment of flow velocity. [5][6][7][8][9] Previous studies showed that the accuracy of the constant flow measurement is within 5%. 2,8 Previously we documented that CVI is a more accurate and consistent method than SDI for determination of blood flow volume 10 ; therefore, we chose CVI as the method of investigation in this study.…”

Peak Velocity Overestimation and Linear‐Array Spectral Doppler

“…The results from this study testing the centroid function on two instruments prove the accuracy of these automatic tracing devices, as compared to the string velocity. A previous study on a time domain system [ 15] showed all velocity estimates performed with a 65-degree angle as accurate representations of the actual velocity. However, under clinical circumstances some problems may be observed us- One approach to reduce the peak veloc1ty error due to intrinsic spectral broadening (ISB) is to redefine the ultrasound beam used for angle correction by the operator.…”