Noncontrast MRA Using Gated 3D FSE with Hybrid Refocusing Angles

Andrew J. Wheaton¹, Robert Anderson¹, Mitsue Miyazaki²

Noncontrast-enhanced MRA using gated 3D FSE (FBI, NativeSPACE, Trance) relies on the inherent flow sensitivity of FSE. A dark blood image acquired during systole is subtracted from a bright blood image acquired during diastole. The flow sensitivity is a function of refocusing angle; high refocusing angles result in bright large arteries, but diminished branch arteries. The opposite is true for low refocusing angles. This study proposes a hybrid method using high refocusing angle in diastole and low refocusing angle in systole. The resultant angiogram contains bright blood in both small and large arteries with minimal increase in background signal.