title: Spiral MRI on a 9.4T Vertical-bore Superconducting Magnet Using Unshielded and Self-shielded Gradient Coils.
abstract: Spiral MRI sequences were developed for a 9.4T vertical standard bore (54 mm) superconducting magnet using unshielded and self-shielded gradient coils. Clear spiral images with 64-shot scan were obtained with the self-shielded gradient coil, but severe shading artifacts were observed for the spiral-scan images acquired with the unshielded gradient coil. This shading artifact was successfully corrected with a phase-correction technique using reference scans that we developed based on eddy current field measurements. We therefore concluded that spiral imaging sequences can be installed even for unshielded gradient coils if phase corrections are performed using the reference scans.
authors.affiliation: Institute of Applied Physics, University of Tsukuba.
authors.forename: Nao
authors.initials: N
authors.lastname: Kodama
authors.affiliation: Institute of Applied Physics, University of Tsukuba.
authors.forename: Ayana
authors.initials: A
authors.lastname: Setoi
authors.affiliation: Institute of Applied Physics, University of Tsukuba.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Kose
mesh_terms: D016477:Artifacts; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods; D000072176:Superconductivity
keywords: eddy current; shielded gradient coil; spiral scan; superconducting magnet