Cardiac cine parallel imaging on a 0.7T open system.
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.
Takizawa
Masahiro
M
Research and Development Center, Hitachi Medical Corporation, Kashiwa, Chiba 277-0804, Japan. takizawa@rd.hitachi-medical.co.jp
Goto
Tomohiro
T
Mochizuki
Hiroyuki
H
Nonaka
Masayuki
M
Nagai
Shizuka
S
Takeuchi
Hiroyuki
H
Taniguchi
Yo
Y
Ochi
Hisaaki
H
Takahashi
Tetsuhiko
T
D016477:Artifacts; D004867:Equipment Design; D006331:Heart Diseases / Q000175:diagnosis*; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000295:instrumentation*; D019047:Phantoms, Imaging