Fat suppression in combination with multiple overlapping thin-slab 3-D acquisition MR angiography: Proposed technique for improved vessel visualization

PURPOSE: To study the parameters of the 1331 fat saturation pulse (saturation pulse flip angle (SPFA) and interpulse delay (τ)) in order to identify values that provide optimal vessel visibility. METHODS: Carotid bifurcations of three healthy subjects were studied. RESULTS: The optimal values for the SPFA and τ were 60° (7.5°, -22.5°, 22.5°, -7.5°) and 2.0-3.0 msec, respectively. At these values there was a 1.56-fold increase (SD = ±.12, P < .01) in the contrast-to-noise ratio between the left internal carotid artery and fat compared to the study without fat saturation. A 3.0-fold increase was noted for the smaller left occipital artery. Additionally, there was no statistically significant reduction in the vessel- muscle contrast-to-noise ratio nor in the absolute vessel signal-to-noise ratio at these values. CONCLUSION: Implementation of fat saturation into carotid MR angiography markedly improves visualization of vascular anatomy without increasing imaging time.