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Capturing fast relaxing spins with SWIFT adiabatic rotating frame spin-lattice relaxation ( T1ρ) mapping.
- Source :
- NMR in Biomedicine; Apr2016, Vol. 29 Issue 4, p420-430, 11p
- Publication Year :
- 2016
-
Abstract
- Rotating frame spin-lattice relaxation, with the characteristic time constant T<subscript>1ρ</subscript>, provides a means to access motion-restricted (slow) spin dynamics in MRI. As a result of their restricted motion, these spins are sometimes characterized by a short transverse relaxation time constant T<subscript>2</subscript> and thus can be difficult to detect directly with conventional image acquisition techniques. Here, we introduce an approach for three-dimensional adiabatic T<subscript>1ρ</subscript> mapping based on a magnetization-prepared sweep imaging with Fourier transformation (MP-SWIFT) sequence, which captures signal from almost all water spin populations, including the extremely fast relaxing pool. A semi-analytical procedure for T<subscript>1ρ</subscript> mapping is described. Experiments on phantoms and musculoskeletal tissue specimens (tendon, articular and epiphyseal cartilages) were performed at 9.4 T for both the MP-SWIFT and fast spin echo (FSE) read outs. In the phantom with liquids having fast molecular tumbling and a single-valued T<subscript>1ρ</subscript> time constant, the measured T<subscript>1ρ</subscript> values obtained with MP-SWIFT and FSE were similar. Conversely, in normal musculoskeletal tissues, T<subscript>1ρ</subscript> values measured with MP-SWIFT were much shorter than the values obtained with FSE. Studies of biological tissue specimens demonstrated that T<subscript>1ρ</subscript>-weighted SWIFT provides higher contrast between normal and diseased tissues relative to conventional acquisitions. Adiabatic T<subscript>1ρ</subscript> mapping with SWIFT readout captures contributions from the otherwise undetected fast relaxing spins, allowing more informative T<subscript>1ρ</subscript> measurements of normal and diseased states. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09523480
- Volume :
- 29
- Issue :
- 4
- Database :
- Complementary Index
- Journal :
- NMR in Biomedicine
- Publication Type :
- Academic Journal
- Accession number :
- 113929640
- Full Text :
- https://doi.org/10.1002/nbm.3474