Prospective cardiac gating of carotid three-dimensional ultrasound
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Quantitative measurements of carotid atherosclerosis can be determined using three-dimensional ultrasound (3DUS). This pilot study involved the development of prospective cardiac gating of 3DUS carotid images to reduce cardiac cycle-derived arterial pulsatility. The method developed uses electrocardiograph signal detection of the cardiac cycle R wave with imaging acquisition delayed in time (deltat) after the R wave is detected. Pulsatility of the common carotid artery was measured by calculating the mean percentage change in arterial cross-sectional area (%deltaA) in moderate atherosclerosis (MA) patients (12% +/- 1%) and healthy volunteers (HVs) (16% +/- 3%) and found that %deltaA was significantly higher for HV than for MA (p = 0.016) when no cardiac gating was used. The cardiac gating method was tested with deltat = 250 ms and deltat = 400 ms in young healthy volunteers and rheumatoid arthritis (RA) patients. For all 3DUS measurements acquired without gating, there was a significant association between %deltaA and age (r2 = 0.20, p = 0.035), and mean %deltaA (in HV and RA) was 13% +/- 5% [95% confidence interval (CI) = 10%-17%]. For deltat = 250 ms mean %deltaA was significantly different and decreased to 7% +/- 3% (95% CI = 5%-10%) and for deltat = 400 ms it was significantly different and decreased to 6% +/- 1% (95% CI = 6%-7%) (p = 0.001 for both comparisons). There was no significant difference in mean %deltaA between gating conditions (p = 0.8); however, the 95% CI for %deltaA was decreased for deltat = 400 ms as compared to deltat = 250 ms. Both gating methods also significantly decreased %deltaA to below the reference standard of 12% +/- 1% for MA (p < 0.01 for both comparisons), suggesting that prospective cardiac gating of carotid 3DUS reduces pulsatility effects in HV and RA to levels lower than observed for much older MA patients.
This is the peer reviewed version of the following article: C Mallett, L Gardi, A Fenster & G Parraga (2009). Prospective cardiac gating of carotid three-dimensional ultrasound. Medical Physics 36(7), 3168-3175, which has been published in final form at https://doi.org/10.1118/1.3134243. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.