ARTERIAL PHASE CAROTID AND VERTEBRAL ARTERY IMAGING IN 3D CONTRAST-ENHANCED MR-ANGIOGRAPHY BY COMBINING FLUOROSCOPIC TRIGGERING WITH AN ELLIPTIC CENTRIC ACQUISITION ORDER

Arterial-phase three-dimensional (3D) contrast-enhanced MR angiograms of the carotid and vertebral arteries from their origins through the c arotid bifurcations were obtained in 20 patients using acquisition tim es over 30 sec by using an MR fluoroscopy-triggered pulse sequence wit h elliptical centric view order. The typical pixel size was 0.8 mm (x) x 1.6 mm (y) x 1.5 mm (z), and 32-48 coronal slices were acquired. Th e fluoroscopic monitoring of bolus arrival was effective in 18 of the 20 cases; two failures were attributed directly to a poor choice of RF coil, To exploit peak arterial-to-venous contrast, the central 3D vie ws were acquired first in the most compact time period possible for th e given TR. For the 18 successfully triggered cases, arterial-phase 3D images were obtained with excellent venous suppression as demonstrate d by an average internal jugular vein to common carotid signal enhance ment ratio of only 0.05 +/- 0.04.