Development of a new compact intraoperative magnetic resonance imaging system: concept and initial experience.
BACKGROUND
Magnetic resonance imaging (MRI) during surgery has been shown to improve surgical outcomes, but the current intraoperative MRI systems are too large to install in standard operating suites. Although 1 compact system is available, its imaging quality is not ideal.


OBJECTIVE
We developed a new compact intraoperative MRI system and evaluated its use for safety and efficacy.


METHODS
This new system has a magnetic gantry: a permanent magnet of 0.23 T and an interpolar distance of 32 cm. The gantry system weighs 2.8 tons and the 5-G line is within the circle of 2.6 m. We created a new field-of-view head coil and a canopy-style radiofrequency shield for this system. A clinical trial was initiated, and the system has been used in 44 patients.


RESULTS
This system is significantly smaller than previous intraoperative MRI systems. High-quality T2 images could discriminate tumor from normal brain tissue and identify anatomic landmarks for accurate surgery. The average imaging time was 45.5 minutes, and no clinical complications or MRI system failures occurred. Floating organisms or particles were minimal (1/200 L maximum).


CONCLUSIONS
This intraoperative, compact, low-magnetic-field MRI system can be installed in standard operating suites to provide relatively high-quality images without sacrificing safety. We believe that such a system facilitates the introduction of the intraoperative MRI.
*Department of Neurological Surgery, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan; ‡Department of Neurosurgery, Hamamatsu University Hospital; §Department of Neurosurgery, Tokyo Metropolitan Police Hospital, Tokyo, Japan; ¶Departments of Neurosurgery, ‖Radiology, #Operative Medicine, and **Anesthesiology, NTT Medical Center Tokyo, Tokyo, Japan; ‡‡Department of Electronics Engineering and Computer Science, Peking University, Beijing, China; §§Cross Tech Corporation, Tokyo, Japan.
Akio
A
Morita
Tetsuro
T
Sameshima
Shigeo
S
Sora
Toshikazu
T
Kimura
Kengo
K
Nishimura
Hirotaka
H
Itoh
Keita
K
Shibahashi
Naoyuki
N
Shono
Toru
T
Machida
Naoko
N
Hara
Nozomi
N
Mikami
Yasushi
Y
Harihara
Ryoichi
R
Kawate
Chikayuki
C
Ochiai
Weimin
W
Wang
Toshiki
T
Oguro
D001932:Brain Neoplasms / Q000601:surgery*; D004867:Equipment Design; D005260:Female; D005910:Glioma / Q000601:surgery*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D016343:Monitoring, Intraoperative / Q000379:methods*; D012189:Retrospective Studies