title: Simultaneous parallel inclined readout image technique.
abstract: Sensitivity-encoded phase undersampling has been combined with simultaneous slice excitation to produce a parallel MRI method with a high volumetric acquisition acceleration factor without the need for auxiliary stepped field coils. Dual-slice excitation was produced by modulating both spin and gradient echo sequences at +/-6 kHz. Frequency aliasing of simultaneously excited slices was prevented by using an additional gradient applied along the slice axis during data acquisition. Data were acquired using a four-channel receiver array and x4 sensitivity encoding on a 1.5 T MR system. The simultaneous parallel inclined readout image technique has been successfully demonstrated in both phantoms and volunteers. A multiplicative image acquisition acceleration factor of up to x8 was achieved. Image SNR and resolution was dependent on the ratio of the readout gradient to the additional slice gradient. A ratio of approximately 2:1 produced acceptable image quality. Use of RF pulses with additional excitation bands should enable the technique to be extended to volumetric acquisition acceleration factors in the range of x16-24 without the SNR limitations of pure partially parallel phase reduction methods.
authors.affiliation: Section of Academic Radiology, Royal Hallamshire Hospital, University of Sheffield, S10 2JF Sheffield, UK. m.n.paley@shef.ac.uk
authors.forename: Martyn N J
authors.initials: MN
authors.lastname: Paley
authors.forename: Kuan J
authors.initials: KJ
authors.lastname: Lee
authors.forename: James M
authors.initials: JM
authors.lastname: Wild
authors.forename: Paul D
authors.initials: PD
authors.lastname: Griffiths
authors.forename: Elspeth H
authors.initials: EH
authors.lastname: Whitby
mesh_terms: D000465:Algorithms; D003205:Computing Methodologies; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D016247:Information Storage and Retrieval / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014584:User-Computer Interface