Silent T₂^* and T₂ encoding using ZTE combined with BURST

Purpose: To obtain T₂^* and T₂ -weighted images as well as quantitative T₂^* , T₂ , and susceptibility maps with a novel, silent 3D imaging method, which combines zero-echo-time (ZTE) imaging with gradient- and spin-echo BURST encoding.

Methods: After a segment of standard ZTE encoding with multiple 3D radial k-space spokes, the direction of traversing k-space is reversed while excitation is switched off. This recalls gradient echoes for each spoke/excitation. This results in multiple images: one FID image from ZTE and multiple BURST echo images at different echo times weighted by a T₂^* decay. By adding a pair of 180° pulses with an appropriate wait period, it is also possible to obtain spin echoes, leading to T₂ -weighted images. Data is reconstructed using standard 3D gridding and Fourier transformation. In vivo feasibility was demonstrated by imaging the brain of multiple healthy volunteers.

Results: It is possible to acquire high-quality T₂^* - and T₂ -weighted brain images in a silent manner. From images acquired with gradient-echo ZTE-BURST, it is possible to extract quantitative T₂^* and magnetic susceptibility maps, whereas the spin echo version yields T₂ maps.

Conclusion: ZTE combined with BURST enables silent acquisition of T₂^* - and T₂ -weighted images with good image quality.