Magnetic resonance angiography of the neck vessels: imaging optimization

The neck vessels of 60 patients were studied by means of magnetic resonance angiography, with gradient-echo FISP sequences with short TR and TE and with a 25 degrees flip angle. To study arterial neck vessels, sequences were acquired on the coronal and on the sagittal planes, centered on the cricoid. The intracranial tract of the vertebral arteries required axial sequences centered under the floor of the sella turcica. Post-processing was obtained with the maximum intensity projection technique. The coronal and sagittal sequences were rotated on the axial plane from 0 degrees to 180 degrees with 15 degrees interval, while axial sequences were rotated on the sagittal plane from 0 degrees to 180 degrees with the same interval. TR, TE and flip angle values were very important for image quality: the thinner the volumes the more effective resolution power and vessel visualization. These volumes should not exceed 1.5 mm. Axial rotations of coronal sequences from -45 degrees to +45 degrees and of sagittal sequences from 60 degrees to 120 degrees were useful for diagnosis. The intracranial tract of the vertebral arteries was clearly depicted after axial sequences and after 75 degrees and 135 degrees sagittal rotations.