T₂ distribution mapping profiles with phase-encode MRI.
Two 1-D phase-encode sequences for T₂ mapping, namely CPMG-prepared SPRITE and spin-echo SPI, are presented and compared in terms of image quality, accuracy of T₂ measurements and the measurement time. The sequences implement two different approaches to acquiring T₂-weighted images: in the CPMG-prepared SPRITE, the T₂-weighting of magnetization precedes the spatial encoding, while in the spin-echo SPI, the T₂-weighting follows the spatial encoding. The sequences are intended primarily for T₂ mapping of fluids in porous solids, where using frequency encode techniques may be problematic either due to local gradient distortions or too short T₂. Their possible applications include monitoring fluid-flow processes in rocks, cement paste hydration, curing of rubber, filtering paramagnetic impurities and other processes accomplished by changing site-specific T₂.
MRI Research Centre, Department of Physics, University of New Brunswick, Fredericton, Canada. opetrov@unb.ca
Oleg V
OV
Petrov
Geir
G
Ersland
Bruce J
BJ
Balcom
D000465:Algorithms; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008422:Materials Testing / Q000379:methods*; D009716:Numerical Analysis, Computer-Assisted; D012815:Signal Processing, Computer-Assisted