title: Cardiac cine parallel imaging on a 0.7T open system.
abstract: BACKGROUND
  Parallel imaging can be applied to cardiac imaging with a cylindrical MRI (magnetic resonance imaging) apparatus. Studies of open MRI, however, are few. This study sought to achieve cardiac cine parallel imaging (or RAPID, for "rapid acquisition through parallel imaging design") with an open 0.7T MRI apparatus.
  
  
  METHODS
  Imaging time was shortened in all slice directions with the use of a dedicated four-channel RF receiving coil comprising solenoid coils and butterfly coils. Coil shape was designed through an RF-coil simulation that considered biological load. The auto-calibration of a 0.7T open MRI apparatus incorporated a modified image-domain reconstruction algorithm. Cine images were obtained with a BASG, or balanced SARGE (steady-state acquisition with rewound gradient echo), sequence. Image quality was evaluated with cylindrical phantoms and five healthy volunteers.
  
  
  RESULTS
  Multi-slice phantom images showed no visible artifacts. Cine images taken under breath-hold with an acceleration factor of two were evaluated carefully. With auto-calibration, the images revealed no visible unfolded artifacts or motion artifacts. RAPID thus improved the acquisition speed, time resolution, and spatial resolution of short-axis, long-axis, and four-chamber images.
  
  
  CONCLUSIONS
  The use of a dedicated RF coil enabled cardiac cine RAPID to be performed with an open MRI apparatus.
authors.affiliation: Research and Development Center, Hitachi Medical Corporation, Kashiwa, Chiba 277-0804, Japan. takizawa@rd.hitachi-medical.co.jp
authors.forename: Masahiro
authors.initials: M
authors.lastname: Takizawa
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Goto
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Mochizuki
authors.forename: Masayuki
authors.initials: M
authors.lastname: Nonaka
authors.forename: Shizuka
authors.initials: S
authors.lastname: Nagai
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takeuchi
authors.forename: Yo
authors.initials: Y
authors.lastname: Taniguchi
authors.forename: Hisaaki
authors.initials: H
authors.lastname: Ochi
authors.forename: Tetsuhiko
authors.initials: T
authors.lastname: Takahashi
mesh_terms: D016477:Artifacts; D004867:Equipment Design; D006331:Heart Diseases / Q000175:diagnosis*; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000295:instrumentation*; D019047:Phantoms, Imaging