High-resolution ZTE imaging of human teeth

MRI with zero echo time (ZTE) is achieved by 3D radial centre-out encoding and hard-pulse RF excitation while the projection gradient is already on. Targeting short-T(2) samples, the efficient, robust and silent ZTE approach was implemented for high-bandwidth high-resolution imaging requiring particularly rapid transmit-receive switching and algebraic image reconstruction. The ZTE technique was applied to image extracted human teeth at 11.7T field strength, yielding detailed depictions with very good delineation of the mineralised dentine and enamel layers. ZTE results are compared with UTE (ultra-short echo time) MRI and micro-computed tomography (μCT), revealing significant differences in SNR and CNR yields. Compared to μCT, ZTE MRI appears to be less susceptible to artefacts caused by dental fillings and to offer superior sensitivity for the detection of early demineralisation and caries lesions.