Search Results

You are looking at 1 - 4 of 4 items for

  • Author or Editor: Yoji Tanaka x
Clear All Modify Search
Restricted access

Maki Mukawa, Tadashi Nariai, Yoshiharu Matsushima, Yoji Tanaka, Motoki Inaji, Taketoshi Maehara, Masaru Aoyagi and Kikuo Ohno

Object

Surgical revascularization is considered an effective treatment for juvenile patients with moyamoya disease (MMD). Yet the long-term outcome in surgically treated patients still needs to be clarified. More than 30 years have passed since the authors' department started intensively treating pediatric patients with MMD using indirect anastomosis techniques. In this study the authors surveyed the current status of these patients.

Methods

Activities of daily living (ADLs) were surveyed and present clinical status was assessed based on the modified Rankin Scale (mRS). Cerebrovascular events subsequent to surgical treatment were also recorded.

Results

Since 1979, 208 patients younger than 19 years of age with MMD were surgically treated and followed up for > 3 years. Data were available on 172 patients (83%), who had been followed up for a mean of 14.3 years (range 3–32 years). Activity of daily living outcomes were as follows: 138 patients (80.2%) had mRS scores of 0–2, 29 (16.9%) a score of 3, 1 (0.6%) a score of 4, 1 (0.6%) a score of 5, and 3 (1.7%) a score of 6. Cerebrovascular events occurred 8 or more years after surgery in 6 patients (3.4%), that is, 6 hemorrhages and 3 infarctions. The cumulative risk of late-onset stroke at 10, 20, and 30 years after surgical intervention was 0.8%, 6.3%, and 10.0%, respectively.

Conclusions

This long-term survey demonstrated that most surgically treated pediatric patients with MMD maintain good ADL outcomes. However, a significant number of new cerebrovascular events occurred more than 10 years after the initial surgery. Additional follow-up will help to identify which events may occur during the adult years of patients treated as children.

Restricted access

Tadashi Nariai, Katsushige Sato, Kimiyoshi Hirakawa, Yoshihisa Ohta, Yoji Tanaka, Kiichi Ishiwata, Kenji Ishii, Kohtaro Kamino and Kikuo Ohno

Object

Intrinsic optical signals in response to somatosensory stimuli were intraoperatively recorded during brain tumor surgery. In the present study, the authors report on the use of this technique as an intraoperative guide for the safe resection of tumors adjacent to or within the sensorimotor cortex.

Methods

In 14 patients with tumors adjacent to or within the sensorimotor cortex, intrinsic optical signals in response to somatosensory stimuli were recorded by illuminating the brain surface with Xe white light and imaging the reflected light passing through a bandpass filter (605 nm). Results were compared with intraoperative recordings of sensory evoked potentials in all 14 patients and with noninvasive mapping modalities such as magnetoencephalography and positron emission tomography in selected patients. In all but two patients, the somatosensory optical signals were recorded on the primary sensory cortex. Optical signals elicited by stimulation of the first and fifth digits and the three branches of the trigeminal nerve were recorded at different locations on the sensory strip. This somatotopic information was useful in determining the resection border in patients with glioma located in the sensorimotor cortex.

Conclusions

Optical imaging of intrinsic signals is a useful technique with superior spatial resolution for delineating the somatotopic representation of human primary sensory cortex. Furthermore, it can be used as an intraoperative monitoring tool to improve the safety and accuracy of resections of brain tumors adjacent to or within the sensorimotor cortex.

Restricted access

Tadashi Nariai, Yoji Tanaka, Hiroaki Wakimoto, Masaru Aoyagi, Masashi Tamaki, Kiichi Ishiwata, Michio Senda, Kenji Ishii, Kimiyoshi Hirakawa and Kikuo Ohno

Object

The authors retrospectively analyzed the data obtained in patients who had undergone l-[methyl-11C] methionine (MET)—positron emission tomography (PET) studies to clarify the relationship between MET uptake and tumor biological features and to discuss the clinical usefulness of MET-PET studies.

Methods

One hundred ninety-four patients with cerebral glioma or suspected glioma underwent PET scanning 20 minutes after injection of MET, whose uptake into the tumor was expressed as a ratio to contralateral healthy brain tissue (T/N ratio). Analyses were performed to determine how MET uptake correlated with tumor pathological features and prognosis. The T/N ratios before and after various treatments were also examined.

There were significant differences in the T/N ratio among the nonneoplastic lesions, low-grade gliomas, and malignant gliomas. Furthermore, there were significant correlations between patient survival and pretreatment T/N ratios. Among patients with malignant gliomas, a significant difference in survival was observed between cases with and without postoperative tumor remnant based on elevated MET uptake. The MET uptake was heterogeneous even among the homogeneous tumor areas demonstrated on MR imaging. Malignant pathological features were detected in the areas with the highest MET uptake. The effectiveness of radiotherapy or chemotherapy was expressed as a significantly decreased T/N ratio in some of the tumor types.

Conclusions

The ability of MET-PET to reflect the biological nature of gliomas makes it an excellent method for monitoring active tumor tissue, and treatments based on its findings should provide a powerful clinical protocol in the course of glioma therapy.

Restricted access

Yoji Tanaka, Tadashi Nariai, Toshiya Momose, Masaru Aoyagi, Taketoshi Maehara, Toshiki Tomori, Yoshikazu Yoshino, Tsukasa Nagaoka, Kiichi Ishiwata, Kenji Ishii and Kikuo Ohno

Object

A multimodal neuronavigation system using metabolic images with PET and anatomical images from MR images is described here for glioma surgery. The efficacy of the multimodal neuronavigation system was evaluated by comparing the results with that of the conventional navigation system, which routinely uses anatomical images from MR and CT imaging as guides.

Methods

Thirty-three patients with cerebral glioma underwent 36 operations with the aid of either a multimodal or conventional navigation system. All of the patients were preliminarily examined using PET with l-methyl-[11C] methionine (MET) for surgical planning. Seventeen of the operations were performed with the multimodal navigation system by integrating the MET-PET images with anatomical MR images. The other 19 operations were performed using a conventional navigation system based solely on MR imaging.

Results

The multimodal navigation system proved to be more useful than the conventional navigation system in determining the area to be resected by providing a clearer tumor boundary, especially in cases of recurrent tumor that had lost a normal gyral pattern. The multimodal navigation system was therefore more effective than the conventional navigation system in decreasing the mass of the tumor remnant in the resectable portion. A multivariate regression analysis revealed that the multimodal navigation system–guided surgery benefited patient survival significantly more than the conventional navigation–guided surgery (p = 0.016, odds ratio 0.52 [95% confidence interval 0.29–0.88]).

Conclusions

The authors' preliminary intrainstitutional comparison between the 2 navigation systems suggested the possible premise of multimodal navigation. The multimodal navigation system using MET-PET fusion imaging is an interesting technique that may prove to be valuable in the future.