Formation of Primary Spin Echoes During Global Coherent Free Precession Improves Longevity of Memory Effect
Rehwald W, Judd R, Kim R, Chen E, Sievers B
Siemens Medical Solutions/ Duke University
We describe a new global coherent free precession technique based on spin echoes (SE-GCFP) rather than gradient echoes (GRE-GCFP). The limitation of GRE-GCFP that signal memory is only about 200 ms due to T2* decay is overcome by repeated spin rephasing. Greater filling distances are achieved. We establish that spin echoes can be formed during GCFP despite the complexity of maintaining global phase coherence in the setting of multi-dimensional blood flow. Phantom data demonstrate that SE-GCFP dramatically increases signal memory, implying that in vivo images will allow visualization of blood flow much further than previously demonstrated for GRE-GCFP.