title: Super-resolved parallel MRI by spatiotemporal encoding.
abstract: Recent studies described an "ultrafast" scanning method based on spatiotemporal (SPEN) principles. SPEN demonstrates numerous potential advantages over EPI-based alternatives, at no additional expense in experimental complexity. An important aspect that SPEN still needs to achieve for providing a competitive ultrafast MRI acquisition alternative, entails exploiting parallel imaging algorithms without compromising its proven capabilities. The present work introduces a combination of multi-band frequency-swept pulses simultaneously encoding multiple, partial fields-of-view, together with a new algorithm merging a Super-Resolved SPEN image reconstruction and SENSE multiple-receiving methods. This approach enables one to reduce both the excitation and acquisition times of sub-second SPEN acquisitions by the customary acceleration factor R, without compromises in either the method's spatial resolution, SAR deposition, or capability to operate in multi-slice mode. The performance of these new single-shot imaging sequences and their ancillary algorithms were explored and corroborated on phantoms and human volunteers at 3 T. The gains of the parallelized approach were particularly evident when dealing with heterogeneous systems subject to major T2/T2* effects, as is the case upon single-scan imaging near tissue/air interfaces.
authors.affiliation: Chemical Physics Department, Weizmann Institute of Science, 76100 Rehovot, Israel.
authors.forename: Rita
authors.initials: R
authors.lastname: Schmidt
authors.forename: Bikash
authors.initials: B
authors.lastname: Baishya
authors.forename: Noam
authors.initials: N
authors.lastname: Ben-Eliezer
authors.forename: Amir
authors.initials: A
authors.lastname: Seginer
authors.forename: Lucio
authors.initials: L
authors.lastname: Frydman
mesh_terms: D000465:Algorithms; D001921:Brain / Q000473:pathology; D017352:Echo-Planar Imaging / Q000379:methods*; D005583:Fourier Analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015233:Models, Statistical; D019047:Phantoms, Imaging; D059629:Signal-To-Noise Ratio; D012984:Software; D013997:Time Factors
keywords: EPI; Echo Time; Echo-Planar Imaging; FOV; FT; Field of View; Fourier Transform; MRI; Magnetic Resonance Imaging; Multi-band chirp pulse; NMR; Nuclear Magnetic Resonance; PE; Parallel MRI; Parallel acquisitions; Phase-Encode; RF; RO; Radio frequency; Read-Out; SAR; SENSE; SP; SPEN; SPatio-temporal ENcoding; SR; Sensitivity Encoding; Spatiotemporal encoding; Specific Absorption Rate; Stationary Point; Super-resolution; TE; Ultrafast MRI; pMRI