Premium
Cerebrospinal fluid–suppressed T 2 ‐weighted MR imaging at 7 T for human brain
Author(s) -
Pan Jullie W.,
Moon Chan Hong,
Hetherington Hoby P.
Publication year - 2019
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.27598
Subject(s) - specific absorption rate , cerebrospinal fluid , nuclear magnetic resonance , magnetic resonance imaging , flip angle , spin echo , susceptibility weighted imaging , nuclear medicine , normalization (sociology) , physics , chemistry , computer science , biomedical engineering , medicine , pathology , radiology , telecommunications , sociology , anthropology , antenna (radio)
Purpose T 2 ‐weighted lesional imaging is most commonly performed using inversion recovery turbo spin echoes. At 7 T, however, this acquisition is limited for specific absorption rate and resolution. This work describes and implements a method to generate CSF‐suppressed T 2 ‐weighted imaging. Methods The strategy uses a driven equilibrium spin‐echo preparation within an inversion recovery with multiple 3D gradient‐echo imaging blocks. Images are combined using the self‐normalization approach, which achieves CSF suppression through optimized timing of individual blocks and minimizes sources of variation due to coil receptivity, T 2 * , and proton density. Simulations of the magnetization‐prepared fluid‐attenuated inversion recovery gradient‐echo (MPFLAGRE) method over T 1 and T 2 relaxation values are performed, and in vivo demonstrations using an 8 × 2 transceiver array in healthy controls are shown. Results The specific absorption rate of the calculated MPFLAGRE sequence is 11.1 ± 0.5 W (n = 5 volunteers), which is 74 ± 2% of the US Food and Drug Administration guidelines. This method acquires both contrasts for CSF suppression with detection of long T 2 components and T 2 ‐weighted imaging in a single acquisition. In healthy controls, the former contrast generates increased signal in the cortical rim and ependyma. A comparison is shown with a conventional 3D SPACE fluid‐attenuated inversion recovery acquisition, and sensitivity to pathology is demonstrated in an epilepsy patient. Conclusion As applied with the 8 × 2 transceiver, the MPFLAGRE sequence generates both whole‐brain contrast suitable for lesional and T 2 ‐weighted imaging at 7 T in fewer than 10 minutes within the US Food and Drug Administration's specific absorption rate guidelines.