PT  - JOURNAL ARTICLE
AU  - Hilgenfeld, T.
AU  - Prager, M.
AU  - Schwindling, F.S.
AU  - Nittka, M.
AU  - Rammelsberg, P.
AU  - Bendszus, M.
AU  - Heiland, S.
AU  - Juerchott, A.
TI  - MSVAT-SPACE-STIR and SEMAC-STIR for Reduction of Metallic Artifacts in 3T Head and Neck MRI
AID  - 10.3174/ajnr.A5678
DP  - 2018 May 24
TA  - American Journal of Neuroradiology
4099  - http://www.ajnr.org/content/early/2018/05/24/ajnr.A5678.short
4100  - http://www.ajnr.org/content/early/2018/05/24/ajnr.A5678.full
AB  - BACKGROUND AND PURPOSE: The incidence of metallic dental restorations and implants is increasing, and head and neck MR imaging is becoming challenging regarding artifacts. Our aim was to evaluate whether multiple-slab acquisition with view angle tilting gradient based on a sampling perfection with application-optimized contrasts by using different flip angle evolution (MSVAT-SPACE)-STIR and slice-encoding for metal artifact correction (SEMAC)-STIR are beneficial regarding artifact suppression compared with the SPACE-STIR and TSE-STIR in vitro and in vivo.MATERIALS AND METHODS: At 3T, 3D artifacts of 2 dental implants, supporting different single crowns, were evaluated. Image quality was evaluated quantitatively (normalized signal-to-noise ratio) and qualitatively (2 reads by 2 blinded radiologists). Feasibility was tested in vivo in 5 volunteers and 5 patients, respectively.RESULTS: Maximum achievable resolution and the normalized signal-to-noise ratio of MSVAT-SPACE-STIR were higher compared with SEMAC-STIR. Performance in terms of artifact correction was dependent on the material composition. For highly paramagnetic materials, SEMAC-STIR was superior to MSVAT-SPACE-STIR (27.8% smaller artifact volume) and TSE-STIR (93.2% less slice distortion). However, MSVAT-SPACE-STIR reduced the artifact size compared with SPACE-STIR by 71.5%. For low-paramagnetic materials, MSVAT-SPACE-STIR performed as well as SEMAC-STIR. Furthermore, MSVAT-SPACE-STIR decreased artifact volume by 69.5% compared with SPACE-STIR. The image quality of all sequences did not differ systematically. In vivo results were comparable with in vitro results.CONCLUSIONS: Regarding susceptibility artifacts and acquisition time, MSVAT-SPACE-STIR might be advantageous over SPACE-STIR for high-resolution and isotropic head and neck imaging. Only for materials with high-susceptibility differences to soft tissue, the use of SEMAC-STIR might be beneficial. Within limited acquisition times, SEMAC-STIR cannot exploit its full advantage over TSE-STIR regarding artifact suppression.CCT-Tporcelain-fused-to-metal nonprecious alloy crown with titanium implantMAVRICmultiacquisition with variable resonance image combinationMSVAT-SPACEmultiple-slab acquisition with view angle tilting gradient based on SPACEnSNRnormalized SNRSEMACslice-encoding for metal artifact correctionSPACEsampling perfection with application-optimized contrasts by using different flip angle evolutionsZ-Tmonolithic zirconia crown with titanium implant