Evaluation of the image contrast of 3D-time-of-flight magnetic resonance angiography at 1.5 T

Abstract

Background: In the three-dimensional time-of-flight (3D-TOF) magnetic resonance angiography (MRA), we evaluated whether the blood flow signal created by the prevention of saturation in blood flow passing through the slab could be more efficiently obtained. Methods: Using the 3D-TOF method, we determined the effects that changes in slab thickness and flip Angle (FA) had on blood flow signal. Circular regions of interest were set on the basilar artery and cerebral parenchyma and the mean signal level was measured. The TOF contrast was calculated from the change in the mean signal level of the measured blood vessel and cerebral parenchyma. Results: Using an FA of 20°, slab thicknesses of 12, 14, 16, and 22 mm were compared, and TOF contrast was found to show significant differences (p<0.05). With an FA of 25°, a significant difference was found between a slab thickness of 22 mm and all other slabs thicknesses (p<0.05). Using an FA of 30°, we compared slab thicknesses of 20 mm or more with those of 16 mm or less, and the TOF contrast showed significantly higher values (p<0.05). Conclusion: The TOF contrast increased when the FA was high, with the results also depending on the slab thickness.