Ikuma Sato

Non-metal Slice Image Overlay Display System Used Inside the Open Type MRI

MRI is now utilized not only for diagnosis but also for intraoperative surgical treatment. In the MRI environment, the surgeon imagines the position of target region by observing pre-acquired images and patient body during the operation, therefore the spatial position of the diseased part depends on the surgeons knowledge and experience. Thus information from the MRI image is not fully utilized. In order to solve this problem, we developed the prototypes of slice image overlay system for open-type MRI, which comprises the MRI compatible display device, image communication, registration system and visualization software, which is adopted to clinical 0.2T Open MRI. Phantom experiments were performed and the TRE of the overlay device was less than 1.0mm at the center of the display.

MRI-Compatible Rigid and Flexible Outer Sheath Device with Pneumatic Locking Mechanism for Minimally Invasive Surgery

To reduce the invasiveness of surgery, we developed an outer sheath device using a flexible toothed link and pneumatic locking mechanism that works with flexible devices used in minimally invasive surgery. The outer sheath can be switched between flexible and rigid modes, and the angle of its tip can be controlled by a nylon wire. All parts of this device are made of plastic and are MRI-compatible. We manufactured a sheath prototype, 300 mm long, with a 20-mm outer diameter, and an 8-mm inner diameter. Experiment results showed that the outer sheath can protect tissues from high insertion force and secure the path for flexible devices. It can follow a curved path with a reasonable radius.

GPU based real-time surgical navigation system with three-dimensional ultrasound imaging for water-filled laparo-endoscope surgery

Presently, a variety of navigation systems are employed in clinical treatments involving neurosurgery, ENT, orthopedic, and head and neck surgery. An ultrasound diagnostic system is used as the navigation system for movable and deformable organs in the abdomen or chest. In this study, we developed a real-time updated 3D ultrasound navigation system that facilitates the high-speed transfer of image data and GPGPU processing for fetal surgery and water-filled laparo-endoscopic surgery (WAFLES). Experimental results showed that our system was able to update every 62 ms. Further, in vivo experimental results showed the ability of our system to guide a surgeon to a target organ during WAFLES in a case where the endoscopic view experienced problems.

MRI compatible manipulator with MRI-guided needle insertion support system

We developed a MRI compatible manipulator system operated under the use of preoperative / intraoperative MR images to realize RFA needle navigation for minimally invasive liver surgery inside an Open MRI gantry. This system has a capability to position a needle to a target inside the MRI gantry by integrating the real space, preoperative/intraoperative MR images and the manipulator coordinate systems with the optical three-dimensional tracking system. Positioning of puncture needle to target is shown in the followings. Puncture needle is positioned with the manipulator for target using preoperative MRI images. Intraoperative MR images including puncture needle and target are acquired by using MR fluoroscopy. Then surgeon inserts the puncture needle to the target. Needle follows the moving target using intraoperative MR images when object/organ is distorted by puncture. We also quantified the MRI compatibility of the manipulator based on MR images. The results showed that MR images have no distortion, and the SNR decreased by 1.2%. Thus the manipulator has high MRI compatibility and is drivable while acquiring MR images. The phantom experiments are conducted to evaluate the needle insertion accuracy, the system positioning and needle insertion accuracy was 0.8 mm±0.29 mm, when the phantom is distorted and the target was moved by puncture. As conclusion, our system is sufficiently accurate and therefore feasible for performing the device guidance inside MRI environment.