Steady-state imaging for visualization of endovascular interventions.

Steady-state imaging techniques offer the potential to couple high spatial and temporal resolution with good signal-to-noise ratio (SNR), which makes them ideally suited for fluoroscopic applications. However, disturbance of the steady state can result in artifacts and substantially reduced signal levels. In this study the use of steady-state imaging techniques was investigated as a means of guiding endovascular interventions with fluoroscopic MRI. Devices containing localized susceptibility defects were shown to disturb the steady-state signal of spins that pass through the magnetic field disturbances. It was demonstrated that these effects are appreciable and can make delineation of interventional devices difficult in the presence of flow. T(1)-shortening contrast agents were shown to dramatically reduce these effects by reducing the time taken to achieve steady state. The addition of a blood pool agent in an in vivo model was found to be necessary for adequate visualization of a dysprosium-marked catheter. Copyright 2003 Wiley-Liss, Inc.