[Vessel contrast and saturation effect at three Tesla in three-dimensional time of flight magnetic resonance angiography]

The purpose of this study was to clarify the effects of the increased field strength of 1.5T vs. 3.0T on blood vessel contrast and saturation in 3D time of flight MR angiography. Vessel contrast and saturation effect were evaluated for various flow velocities and flip angles using a steady-state flow phantom. The results showed increased vessel contrast and decreased saturation of blood on 3.0T compared to 1.5T, due to the following factors: 1) sufficient saturation of stationary tissue by extended T1 relaxation time, 2) increased signal-to-noise ratio (SNR), and 3) high in-flow effect. However, the blood signal on 3.0T revealed a strong tendency to phase dispersion compared to that of 1.5T. Therefore, in order to exploit the characteristic of high field strength in 3.0T, it is suggested that adequate consideration of these factors is important in setting the image acquisition parameters.