Cerebrospinal fluid-suppressed T₂ -weighted MR imaging at 7 T for human brain

T₂ -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 T₂ -weighted imaging.

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, T₂^* , and proton density. Simulations of the magnetization-prepared fluid-attenuated inversion recovery gradient-echo (MPFLAGRE) method over T₁ and T₂ relaxation values are performed, and in vivo demonstrations using an 8 $$ 2 transceiver array in healthy controls are shown.

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 T₂ components and T₂ -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.

As applied with the 8 $$ 2 transceiver, the MPFLAGRE sequence generates both whole-brain contrast suitable for lesional and T₂ -weighted imaging at 7 T in fewer than 10 minutes within the US Food and Drug Administration's specific absorption rate guidelines.