[Time-resolved three-dimensional contrast-enhanced MR angiography of the carotid artery]

Contrast-enhanced MR angiography (ceMRA) allows practical carotid arteriography without venous enhancement. However, it requires some intricate preparation such as a test bolus of the contrast agent or determination of the tracking volume even in the automatic triggering Smartprep system. The purpose of this study was to obtain carotid ceMRA without any preparation by means of a repeated multiple ultrashort three-dimensional MRA sequence (e3d56), i.e., time-resolved MRA (trMRA). Twenty-three patients underwent sagittal trMRA using a 1.0-Tesla superconducting unit. Multiple projection angiograms are acquired in three contiguous phases with a time resolution of 6 seconds per slab, including 10 partitions, after a bolus injection of 10 ml of Gd-DTPA followed by 20 ml of saline at 2 ml/sec. In all patients, the signal from the arteries could be separated from that of the veins in at least one phase. Carotid trMRA with 6-sec temporal resolution is a reliable technique for selective arteriography, avoiding the necessity of timing the contrast agent bolus.