Quantification of blood flow in the carotid arteries - Comparison of Doppler ultrasound and three different phase-contrast magnetic resonance imagingsequences

RATIONALE AND OBJECTIVES. To compare blood flow velocities in the carotid a rteries measured with three different magnetic resonance (MR) phase-contras t imaging techniques and with percutaneous Doppler ultrasound. METHODS. Fourteen healthy male volunteers with a mean age of 33 +/- 3.8 yea rs were studied. Ultrasound and MR phase velocity mapping of both common ca rotid arteries (n = 28) was performed within 5 hours. A two-dimensional fas t low-angle shot sequence with retrospective cardiac gating, a sequence wit h prospective cardiac triggering, and a breath-hold sequence with prospecti ve cardiac triggering were used. Resistance indexes and pulsatility indexes were calculated for all modalities. RESULTS. The comparison of flow velocities obtained with ultrasound and the different MR techniques led to a moderate correlation of the retrospective gated and prospective triggered MR techniques (eg, r = 0.73 for maximum sy stolic velocity). The worst correlation was found between the breath-hold t echnique and retrospective cardiac gating (eg, r = 0.004 for pulsatility in dex). There was a weak correlation of all three MR sequences compared with ultrasound (r = 0.19-0.60) CONCLUSIONS. A moderate correlation was found between velocities and indexe s measured with the prospective cardiac-triggered phase-contrast MR techniq ue and the retrospective cardiac-gated phase-contrast MR technique. A weak correlation was found between the three different MR techniques and ultraso und, as well as between the breath-hold prospective cardiac-triggered MR se quence and both of the other MR sequences. The influence of temporal and sp atial resolution on MR phase-contrast velocity mapping was confirmed.