T2 relaxometry has the potential to become an important quantitative MRI biomarker thanks to its sensitivity to pathology. However, acquiring high-resolution isotropic T2 maps is challenging due to signal-to-noise and specific absorption rate constraints. We present a T2-mapping method for ultra-high-field MRI based on an optimized T2-prepared acquisition with compressed sensing acceleration. The T2 preparation uses adiabatic pulses in conjunction with a segmented FLASH sequence to obtain uniform whole-brain T2 weighting despite B1 inhomogeneity. Preliminary tests show good signal homogeneity for images and maps obtained in a scan time compatible with volunteer studies.