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Eiju Watanabe

Publications and source records attributed to Eiju Watanabe.

10 recordsLinked to original sources
PubMed2007

Virtual spatial registration of stand-alone fNIRS data to MNI space.

The registration of functional brain data to common stereotaxic brain space facilitates data sharing and integration across different subjects, studies, and even imaging modalities. Thus, we previously described a method for the probabilistic registration of functional near-infrared spectroscopy (fNIRS) data onto Montreal Neurological Institute (MNI) coordinate space that can be used even when magnetic resonance images of the subjects are not available. This method, however, requires the careful measurement of scalp landmarks and fNIRS optode positions using a 3D-digitizer. Here we present a novel registration method, based on simulations in place of physical measurements for optode positioning. First, we constructed a holder deformation algorithm and examined its validity by comparing virtual and actual deformation of holders on spherical phantoms and real head surfaces. The discrepancies were negligible. Next, we registered virtual holders on synthetic heads and brains that represent size and shape variations among the population. The registered positions were normalized to MNI space. By repeating this process across synthetic heads and brains, we statistically estimated the most probable MNI coordinate values, and clarified errors, which were in the order of several millimeters across the scalp, associated with this estimation. In essence, the current method allowed the spatial registration of completely stand-alone fNIRS data onto MNI space without the use of supplementary measurements. This method will not only provide a practical solution to the spatial registration issues in fNIRS studies, but will also enhance cross-modal communications within the neuroimaging community.

Adult↗
PubMed2006

[Development of new surgical tools, Q-PAL and HP-Jet for endoscopy only used unilateral transnasal approach for pituitary adenomas].

UNLABELLED: The aim of this study is to present surgical techniques and results of endoscope-assisted transnasal approach (TNA) for pituitary adenomas. It is a new alternative for Hardy's surgery (TSS). We performed TNA assisted by only endoscope through single nostril. METHOD: We enter the sphenoid sinus directly through the natural ostium and ablate neither the nasal septum nor the vomer bone. We found the hardest problem of this method resides in its deep and narrow working space which obstructs usage of two tools at same time. To overcome this problem we developed two surgical tools, Q-PAL and HP-Jet. Q-PAL is combination of PAL and suction. We place flexible PAL wire electrode through suction tube so as PAL tip protrudes from suction tip. This eliminates coagulation smoke which otherwise disturbs surgeons view. HP-Jet is a combination of a suction tool and an irrigator. The irrigator is connected to syringe containing saline. Saline is injected manually from tip bursting up tumor tissue with its jet pressure. It is safe and effective instrument suitable for extirpation of rather fragile tissue like adenomas existing in deep and blind spaces. CASES: Since 2004 we have operated on 16 patients using endoscopic TNA. Eight were non-functioning adenomas, and 8 functioning. RESULTS: Results of surgery were compared with those of 10 cases operated by TSS. More than 70% removal of adenoma was achieved in 75% of cases with TNA, but in only 71% with TSS. Postoperative CSF rhinorrhea was seen in one case. Four cases showed postsurgical transient diabetes insipidus. We had no case with postsurgical infection. With the help of instruments having multiple functions in single probe such as Q-PAL and HP-Jet, we can execute endoscopic TNA more smoothly and more safely.

Adenoma↗
PubMed2006

[A case of pineal pure germinoma metastasized to the lumbosacral extradural space 8 years after initial therapy. Case report and review of literature].

An 11-year-old boy first presented with a pineal tumor identified by neuroimaging but without positive serum or cerebrospinal fluid markers. The tumor disappeared after the craniotomy and following cranial irradiation. The pathologic diagnosis of the tumor was of a pure germinoma. Eight years later he returned to the hospital with spinal epidural metastasis from the pineal germinoma and required surgery. Intraoperative findings showed that the spinal tumor was solitarily located in the epidural space. Pathologically the tumor was a pure germinoma metastasis. He was treated by a combination of whole spinal irradiation and chemotherapy. The tumor disappeared after the therapy. A pineal germinoma occasionally disseminates through the ventricular system and spinal subarachnoid region. However, a solitary spinal epidural metastasis from pineal germinoma has rarely been reported. Regarding the route of this metastasis, we speculate that the CSF dissemination of the germinoma cells occurred first and some of those cells were trapped in the spinal nerve sleeve and extended into the epidural space.

Adult↗
PubMed2006

[Only used unilateral transnasal approach applied endoscopic sinus surgery for pituitary adenomas].

Endoscope-assisted transnasal approach (TNA) for pituitary adenoma is a new alternative for Hardy's surgery (TSS). We performed TNA using only an endoscope through unilateral nostril. In our approach to sphenoid sinus, we apply method of endoscopic sinus surgery (ESS-TNA). We enter the sphenoid sinus directly through the natural ostium and do not brake the nasal septum nor vomer bone. Since September 2004 we had operated on 12 patients by endoscopic TNA. Six were non-functioning adenomas, and 6 were functioning adenomas. We are first to open the ethomoid sinus to make the space for middle concha to be displaced laterally. Secondary, we widen the natural ostium of the sphenoid sinus, retracting the middle concha laterally. The results were compared with those in 10 cases by TSS operated in our institute. Adenoma removal more than 80% was achieved in 58% by endoscopic TNA whereas in 50% by TSS. We had no case with postsurgical infection. Transient DI occurred in 4 cases and 1 case showed permanent. CSF rhinorrhea was seen in the case having small empty sellae in front of adenoma. For this case, we packed the fat tissue at the floor of the sella with endoscope under local anesthesia to close the fistula. Three cases that had hemianopsia before surgery showed the recovery postoperatively. In 6 functional adenoma, postoperative endocrinological examinations showed normalization in 3 cases and improvements in 3 cases. Postsurgical hospitalization days were 11.4 by endoscopic TNA whereas 15.4 by TSS. Our method showed same or better results than TSS in the removal rate and complication rate whereas the postoperative duration of nasal packing and hospitalization days were shorter than TSS.

Adenoma↗
PubMed2004

Cerebral blood oxygenation after cerebrospinal fluid removal in hydrocephalus measured by near infrared spectroscopy.

BACKGROUND: The cerebrospinal fluid (CSF) tap test has been used for the diagnosis of chronic hydrocephalus to identify the candidates for surgical CSF shunting. However, a high rate of false negative results limits it utility. The purpose of this study is to investigate whether the concomitant monitoring of cerebral hemodynamics by near infrared spectroscopy (NIRS) can improve the diagnostic accuracy of the tap test. METHODS: Thirteen patients with dilated ventricular system were candidates for this study. We assessed for the patterns of cerebral blood oxygenation (CBO) change in hydrocephalus to determine whether CBO change after CSF removal is useful for selecting shunt candidates. RESULTS: Patients who showed clinical improvement following CSF shunting had a characteristic CBO change with increases in the concentration of oxyhemoglobin (Oxy-Hb), and patients without improvement during continuous CSF drainage test showed no increase in Oxy-Hb. CONCLUSION: The current data suggests that CBF increases after CSF removal in hydrocephalus. Although the patients utilized in the present study had secondary chronic hydrocephalus, we speculate that these data could be applied to patients with idiopathic chronic hydrocephalus. Further investigation would be of benefit.

Adult↗
PubMed2004

Memory function decline over 18 months after selective amygdalohippocampectomy.

We report on a 22 year-old woman with left temporal lobe epilepsy who had suffered complex partial seizures since childhood. At 19 years 10 months of age she underwent selective amygdalohippocampectomy, which resulted in a complete cessation of seizures. Preoperatively, the Logical Memory II section of the WMS-R revealed poor logical memory function. Postoperatively, the patient's scores on several neuropsychological tests had deteriorated, namely, the Miyake Paired-Associate Word Learning Test (related and unrelated pairs), several sections of the WMS-R (Figural Memory, Logical memory I, Visual Reproduction II, Visual Paired Associates I, and Verbal Paired Associates I and II), and the BVRT-R. In particular, her scores on the Visual Paired Associates I, Verbal Paired Associates I and II sections of the WMS-R, and the BVRT-R not only declined at one and three months post-surgery, but also showed progressive deterioration at 16 and 18 months post-surgery. It should be kept in mind that selective amygdalohippocampectomy can result in progressive postoperative, deterioration in some aspects of memory function.

Adult↗
PubMed2003

An event-related optical topography study of cortical activation induced by single-pulse transcranial magnetic stimulation.

To visualize cortical activations during transcranial magnetic stimulation (TMS), it is necessary to measure those activations at high spatiotemporal resolution while preventing interference with the magnetic property of a coil. One suitable method that satisfies these demands is optical topography (OT), which has been used in cortical activation studies. In the present study, single-pulse TMS was applied to the left primary motor area, and cortical responses at the stimulation site were measured simultaneously with event-related OT. When TMS was applied at 110% motor threshold (MT), we observed significant oxyhemoglobin increases that were both time-locked and correlated with the hemodynamic basis function. Moreover, when TMS was applied at 90% MT, significant oxyhemoglobin increases were detected even though there were no motor-evoked potentials. These results demonstrate that OT can directly measure cortical responses to subthreshold single-pulse TMS, independent of the afferent feedback from the peripheral neuromuscular activity.

Adult↗
PubMed2002

Selective priming of syntactic processing by event-related transcranial magnetic stimulation of Broca's area.

It remains controversial whether Broca's aphasia is an articulatory deficit, a lexical-access problem, or agrammatism. In spite of recent neuroimaging studies, the causal link between cortical activity and linguistic subcomponents has not been elucidated. Here we report an experiment with event-related transcranial magnetic stimulation (TMS) to clarify the role of Broca's area, more specifically, the left inferior frontal gyrus (F3op/F3t), in syntactic processing. An experimental paradigm contrasted sentences requiring syntactic decisions with those requiring semantic decisions. We found selective priming effects on syntactic decisions when TMS was administered to the left F3op/F3t at a specific timing, but not to the left middle frontal gyrus (F2). Our results provide direct evidence of the involvement of the left F3op/F3t in syntactic processing.

Adult↗
PubMed2002

Focus diagnosis of epilepsy using near-infrared spectroscopy.

PURPOSE: We sought to establish a noninvasive method for focus diagnosis of epilepsy. METHODS: We examined the use of multichannel near-infrared spectroscopy (NIRS). It is known as a noninvasive method of functional brain mapping. We monitored cerebral blood volume change with NIRS during long-term EEG monitoring of epilepsy in 32 cases with intractable epilepsies to diagnose the epileptogenic focus. RESULTS: In 96% of cases, NIRS showed significant hyperperfusion in the side of seizure foci, whereas ictal SPECT showed hyperperfusion in 69% of cases. CONCLUSIONS: Ictal NIRS is a reliable method to evaluate the focus side in epilepsy, especially when it is coupled with ictal SPECT.

Adolescent↗