Hiroshi Iseki

Mid-Infrared Robotic Laser Surgery System in Neurosurgery

There is certain limitation to do the perfect extraction of the tumors by conventional manual surgery, because the area close to the boundary between tumors and normal brain tissue is usually left in order to keep away from destruction of normal area. For the purpose to treat such the boundary area, a computer controlled robotic laser surgery system has been developed. This system is characterized by the mid-infrared laser device which can perform less invasive precise surgery with low output power (<1.0W), and the computer controlled system which can realize the ablation of designated area on brain surface within 0.5mm dislocation. For the further study, aiming to apply to use in vivo, we have developed an auto-focus system for laser irradiation. From the results of our animal study, the system enables to maintain the focal point of the laser head on brain surface to realize constant ablation in the designated area.

Video Information Management System for Information Guided Neurosurgery

As the boundary between glioblastoma and normal tissue is unclear, precise resection is required to reduce the risk of post-operative adverse event such as aphasia and to elongate residual life of the patient by resecting tumor region completely. Surgeons use various information such as preoperative and intraoperative image, surgical navigation, pathological images, and so on, to decide resection line. In conventional operating room, information is dispersed. In this study, video information integration system was implemented using dedicated hardware video mixer. In clinical evaluation, pre-set window layout was selected just by pushing a button, and neither delay nor noise was observed. In the future study, we will implement automatic layout changing system depending on the surgical scenario.

Development of Hitchcock stereotactic frame for intraoperative open MRI

We have introduced open MRI into the operating room. When taking intraoperative open MR (iMR) images conventionally, since it was impossible to have used a conventional head coil for diagnosis because of need of space, we used to wrap the body coil around the patient’ head to get signal. However, the body coil was less sensitive, wrapping the coil was very rough. Then we have developed Hitchcock Coil for intraoperative open MRI (iMRI). Hitchcock Coil works not only as more sensitive receiving coil than conventional one, but also as iMRI-guided Hitchcock stereotactic device (Hitchcock device), that is to say Navigation System using markers for iMRI. This time we confirmed that Hitchcock Coil were more excellent than the conventional receiving coil in respect of contrast and space resolution, and were acceptable to iMRI.

Brain temperature measurements during speech in patients with brain tumors: New methods for identification of the speech area in intraoperative brain mappings

Abstract In the present study, the usefulness of a functional thermography (fTG) for determining critical speech area was assessed in three patients with brain tumors in language areas. The results of the fTG were also compared with functional MRI (fMRI), subdural electrodes and intraoperative cortical stimulations. Measurements of the regional brain temperature were done using the thermography. The temperature increased after 8–10 s later from the speech and decreased with a few seconds delay after interruption of the task. The areas of increased temperature were coincident with the bridging veins and functional areas identified using fMRI and direct cortical stimulations. The use of fTG increases the sensitivity and specificity for the detection of essential motor language area.

Classification of patient's reaction in language assessment during awake craniotomy

Surgical video recording is widely used in operation rooms in order to analyze such as surgical procedures and intraoperative incident detection. Therefore, a number of useful operation video records are stored in the hospitals. It is considered that these video records contain significant information, so it is needed to utilize these video data. In awake craniotomy, which is one of the advanced neurological surgery, surgeon performs direct electrical stimulation to patients brain area during linguistic tasks(such as, naming objects or generating verbs) in order to detect brain functional areas. The electrical stimulation of the cortical speech area causes temporary speech arrest. Hence, video segments which speech arrest is caused are significant in terms of surgical video analysis. The electrical stimulation timings are obtained from sound information, however that segments are not tagged speech arrest or not. In this paper, we report on the performance of a classification method for classifying patients response for linguistic tasks just after electrical stimulation. In order to extract patients speech features, we used melfrequency cepstrum coefficient(MFCC) and its delta parameters which are often used in speech recognition. We used Relevance Vector Machine(RVM) and Support Vector Machine(SVM) for classification and compared their results. We applied RVM and SVM for extracted patients speech features and evaluated in F-measure. The classifier achieves in classification rates about 80[%] in 10-fold cross validation. The result shows that speech features are effective for classifying patients responses.

LAN based 3D digital ultrasound imaging system for neurosurgery

Two-dimensional (2D) ultrasound imaging system is very convenient to use during the operation, but its resolution is inferior to that of MRI. It is not easy to increase the resolution of the ultrasound imaging system considering its principle. It will be easier for surgeons to comprehend the condition of the tissue when the image data is displayed in three-dimensional (3D) forms. A digital 3D ultrasound imaging system for neurosurgery has been developed in this chapter. This system acquires 2D image data through Local Area Network (LAN) directly. It reconstructs 3D volume from a series of 2D slices by mechanical scanning of the ultrasound probe and renders 3D volume at high speed. A diagnostic ultrasound imaging-system was PC-based and communication program made it possible to transfer image datasets to other computers through LAN. Volume data were reconstructed from sequence of 2D images acquired during the probe rotation. Another PC processed graphics, controlled the motor, and image data were transferred to the memory of it from the diagnostic ultrasound machine. The system was tested in two clinical cases. It helped surgeons to understand the condition of the diseased part during the operation.