The most widely performed test for patients suspected of having carotid atherosclerosis is Doppler ultrasound (DUS).
Unfortunately, limitations in sensitivity and specificity prevent DUS from being the sole diagnostic tool. Novel DUS
velocity-derived parameters, such as turbulence intensity (TI), may provide enhanced hemodynamic information within
the carotid artery, increasing diagnostic accuracy. In this study, we evaluate a new technique for recording, storing and
analyzing DUS in a clinical environment, and determine the correlation between TI and conventional DUS
measurements. We have recruited 32 patients with a mean age of 69±11 yrs. An MP3 recorder was used to digitally
record Doppler audio signals three times at three sites: the common carotid artery, peak stenosis and region of maximum
turbulence. A Fourier-based technique was used to calculate TI, facilitating clinical application without additional ECGgating
data. TI was calculated as the standard deviation of Fourier-filtered mean velocity data. We found that TI and
clinical PSV were linearly dependent (P<0.001) within the region of maximum turbulence and the precision of all TI
measurements was found to be 14%. We have demonstrated the ability to record Doppler waveform data during a
conventional carotid exam, and apply off-line custom analysis to Doppler velocity data to produce measurements of TI.