Intracranial MR angiography: comparison of single-volume three-dimensional time-of-flight and multiple overlapping thin slab acquisition techniques.

OBJECTIVE: Time-of-flight (TOF) MR angiography has continued to evolve during the past few years. Signal loss due to flow saturation is a major problem of single-volume (slab) three-dimensional (3D) TOF technique. A multislab 3D TOF method, multiple overlapping thin slab acquisition (MOTSA), shows decreased sensitivity to the effects of flow saturation and therefore should result in better images. SUBJECTS AND METHODS: To evaluate the difference between MOTSA and the traditional single-volume 3D TOF techniques, we performed sequential, location-matched studies in 17 prospectively chosen patients with intracranial vascular abnormalities. All MOTSA and 3D TOF images were obtained after cut-film or 1024 digital angiography. RESULTS: According to specific criteria, abnormalities were better visualized with the MOTSA technique than with the single-volume 3D TOF technique. The difference was most marked in patients with more complex vascular abnormalities. CONCLUSION: We conclude that MOTSA is better than single-volume 3D TOF for showing intracranial abnormalities. The major advantage of MOTSA is decreased sensitivity to flow saturation.