Effects of dynamic range variations on the Doppler flow velocities of common carotid arteries

Abstract

IntroductionDoppler ultrasound is the commonest diagnostic tool used to evaluate the internal, external and common carotid arteries (CCA). Peak systolic velocity (PSV) is the best Doppler parameter for quantifying carotid artery degree of stenosis. Materials and methodsNormal Doppler waveforms of 24 CCA from 12 healthy individuals of age 22–28 years were analysed in the department of radiology, NEIGRIHMS, Shillong. PSV, EDV and RI at 9 MHz transducer frequencies and variable DR of 35,45,55,65,75 &85 Decibels (dB) were compared. Statistical analysisOne-Way repeated measures ANOVA; parameters expressed as Mean ± SEM. p value significant at <0.05. AimTo study the effect of variable dynamic ranges (DR) on the PSV, end diastolic velocity (EDV) and resistive index (RI) of CCA. ResultsFor PSV of the right CCA at 9 MHz, there was significant differences on variable DR as determined by One-Way repeated measures ANOVA [F (5, 55) = 5.54, p < 0.05]. There was however no significant differences in the PSV of the left CCA; EDV and RI at variable dynamic ranges in both the right and left CCA. Summarised mean value for all PSV of both sides shows significant difference between variable dynamic ranges as determined by One-Way repeated measures ANOVA [F (5, 115) = 2.85, p < 0.05] and Post-hoc analysis revealed that there was a significant difference only between 35 dB to 55 dB and 85 dB. ConclusionVariable DR while improving sonographic contrast result in significant variation of PSV in the CCA particularly on the right CCA.