Akio Morita MD, PhD, Presenter: Nothing to Disclose

Toshikazu Kimura MD, Abstract Co-Author: Nothing to Disclose

Tetsuro Sameshima MD, PhD, Abstract Co-Author: Nothing to Disclose

Toru Machida MD, Abstract Co-Author: Nothing to Disclose

Yoshio Imai, Abstract Co-Author: Nothing to Disclose

Weimin Wang PhD, Abstract Co-Author: Nothing to Disclose

Toshiki Oguro PhD, Abstract Co-Author: Employee, Yoshida Mfg Co Ltd

Magnetic resonance imaging (MRI) during surgery has been proven to improve surgical outcome. However, current intraoperative MRI system is large and requires large scale construction to install the unit. Also, large system produces wide magnetic field, which significantly constrain surgical procedures. Although there is a compact mobile MRI system available, imaging quality of this system is not ideal for surgical information. To overcome such dilemmas of intraoperative MRI imaging, we have developed a new compact intraoperative MRI system and started clinical application.  

This new MRI system was built with following system characteristics; 1) Magnetic gantry: permanent magnet 0.23T, 2) inter polar distance of 32cm 3) the gantry system weighs 2.8 tons, and 4) the 5 gauss line is with in the circle of 2.6m in diameter. To obtain high quality image during neurosurgical setting, we created a new field-of- view head coil system, which provides uniform magnetic field covering whole cranium and can be attached to the head clamp system during surgery. We also have developed a new Canopy style radio-frequency shield system to create minimal noise space with high signal/noise ratio in routine operative suite. This shield is made with argentine mesh through which we can observe patient condition. In Sept. 2010, the 1st system was installed and clinical trial was initiated. The system was applied in ten clinical cases so far.

The size of this system is significantly smaller than the previous intraoperative MRI systems. With new head clamping and head coil system, clinical application was done without significant limitations. High quality T2 and FLAIR images were obtained enough to discriminate tumor from normal brain tissue and to identify anatomical landmark to achieve accurate surgery. Average image acquisition time was 52minutes. No clinical complication or system failure was encountered.

A new compact intraoperative MRI system was developed. This system could be installed in routine operative suite without causing limitation in surgical procedures. This system provided high quality images, which should improve surgical quality control.  

Although previous intraoperative MRI systems are not suitable for routine surgical setting, this system can be installed easily and provide high quality image, whcih shoud improve quality of care.

Morita, A, Kimura, T, Sameshima, T, Machida, T, Imai, Y, Wang, W, Oguro, T, Development of a New Compact Intraoperative Magnetic Resonance Imaging System: New Concept in Radiofrequency Shield and Initial Clinical Experience.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11014703.html