This provides for improvement in signal in a poststenotic site and thus a reduction in signal loss in a poststenotic region of a blood vessel. This decrease in saturation allows more anatomic territory to be evaluated within a single scan sequence. This also leads to a decrease in poststenotic signal loss, not because intravoxel dephasing is decreased, but because there is more signal at the start before dephasing takes place. Larger flip angles yield greater blood signal and improved suppression of stationary background tissue. Gadolinium is safe and not nephrotoxic.
Adverse reactions are infrequent and serious reactions are rare.
With 2D TOF technique, scan times are 4 to 6 minutes, increasing the possibility of motion or respiratory artifacts, which can degrade image quality. This can be used to decrease acquisition time or improve image resolution. While 2D TOF technique yields good signal uniformity and sensitivity to slow flow, it is more time consuming, resulting in a greater chance of motion artifact. Respiration can lead to saturation-induced artifacts, such as bright bands in nonvascular tissues on MIP images or dark bands within the actual vessel. Pulsatile flow can lead to variations in signal saturation in an acquisition, which results in ghosting of the vessel.