title: Interleaved echo planar imaging on a standard MRI system.
abstract: This work describes an interleaved echo planar imaging (EPI) method for use on a standard whole body scanner. The data acquisition is divided into two to eight repetitions rather than one to two, as implemented by dedicated EPI systems. Interleaving allows the use of a lower sampling bandwidth with a significant increase in signal-to-noise. The method also has the advantages of relative ease of implementation, no need for postprocessing to remove image distortion, and no need for shimming on a case-by-case basis. The interleaved EPI method was applied to two applications ideally suited to EPI: breathhold T2-weighted abdominal imaging and functional imaging. In vivo liver-lesion contrast as measured in a 35-patient study showed increased contrast for the interleaved EPI by an average factor of 1.21 (+/- 0.34) over conventional spin-echo imaging. CNR measurements showed the EPI to be comparable with conventional spin echo with a relative factor of 1.00 (+/- 0.36). Functional imaging with an eight-shot interleaved EPI sequence provided 128 x 128 images of cerebral activation during bilateral finger tapping.
authors.affiliation: Magnetic Resonance Laboratory, Mayo Clinic, Rochester, Minnesota 55905.
authors.forename: K
authors.initials: K
authors.lastname: Butts
authors.forename: S J
authors.initials: SJ
authors.lastname: Riederer
authors.forename: R L
authors.initials: RL
authors.lastname: Ehman
authors.forename: R M
authors.initials: RM
authors.lastname: Thompson
authors.forename: C R
authors.initials: CR
authors.lastname: Jack
mesh_terms: D000005:Abdomen / Q000033:anatomy & histology; D017352:Echo-Planar Imaging / Q000379:methods*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*