Biomedical subjects

Kenji Ino

Publications and source records attributed to Kenji Ino.

7 recordsLinked to original sources

PubMed2006

[Utility of axial images in an early Alzheimer disease diagnosis support system (VSRAD)].

In recent years, voxel-based morphometry (VBM) has become a popular tool for the early diagnosis of Alzheimer disease. The Voxel-Based Specific Regional Analysis System for Alzheimer's Disease (VSRAD), a VBM system that uses MRI, has been reported to be clinically useful. The able-bodied person database (DB) of VSRAD, which employs sagittal plane imaging, is not suitable for analysis by axial plane imaging. However, axial plane imaging is useful for avoiding motion artifacts from the eyeball. Therefore, we created an able-bodied person DB by axial plane imaging and examined its utility. We also analyzed groups of able-bodied persons and persons with dementia by axial plane imaging and reviewed the validity. After using the DB of axial plane imaging, the Z-score of the intrahippocampal region improved by 8 in 13 instances. In all brains, the Z-score improved by 13 in all instances.

Alzheimer Disease↗

PubMed2006

[Examination of an imaging method in early Alzheimer disease diagnosis support system (VSRAD)].

The use of voxel-based morphometry (VBM) has recently become a popular tool for the early diagnosis of Alzheimer disease. The Voxel-Based Specific Regional Analysis System for Alzheimer's Disease (VSRAD) is a clinically useful VBM that employs MRI. However, there has been insufficient information about the influence of the image pickup apparatus and imaging conditions in terms of the value calculated by the sensitivity correction. We therefore reviewed this problem in a volunteer who provided consent. We were able to confirm reproducibility under the same conditions. When changing the image pickup apparatus and conditions, the average Z-score of 0.18+/-0.21 became larger, and the change in Z-score increased when imaging was done in the axial plane. Further, the average Z-score of 0.06+/-0.21 for sensitivity correction use was high on average by 0.19+/-0.16 for phased-array uniformity enhancement (PURE) and low for surface coil intensity correction (SCIC).

Adult↗

PubMed2005

Functional monitoring for visual pathway using real-time visual evoked potentials and optic-radiation tractography.

OBJECTIVE: It has been difficult to obtain anatomic and functional information about the visual pathway during neurosurgical operations. The aim of this study was to combine the information of the visual evoked potentials (VEPs) and the anatomic navigation of the optic radiation by diffusion tensor imaging-based tractography for functional monitoring of the visual pathway. METHODS: The subjects were two patients with brain lesions adjacent to the visual pathway. Diffusion tensor imaging-based tractography of the optic radiation was performed by selecting appropriate regions of interest and by fractional anisotropy. During surgery, cortical VEPs were recorded continuously under general anesthesia with sevoflurane. In Patient 2, the results of optic radiation tractography were imported to a neuronavigation system to better understand the spatial relationships between the lesions and the visual pathway (functional neuronavigation). RESULTS: In Patient 1, the lesion did not seem to be attached to the optic radiation, and VEP profiles remained stable during resection. In Patient 2, who had a lesion adjacent to the posterior horn of the lateral ventricle, VEPs suddenly diminished when resection reached the optic radiation as illustrated on the neuronavigation system. As a result, complete left hemianopia developed after surgery in Patient 2. CONCLUSION: We confirmed functional correlations of the results of diffusion tensor imaging-based tractography by monitoring intraoperative VEPs. The combination of continuous VEP and optic-radiation tractography is reliable to monitor the visual function and is helpful in performing neurosurgical planning near the visual pathway.

Adult↗

PubMed2005

Combined use of tractography-integrated functional neuronavigation and direct fiber stimulation.

OBJECT: The aim of this study was better preoperative planning and direct application to intraoperative procedures through accurate coregistration of diffusion-tensor (DT) imaging-based tractography results and anatomical three-dimensional magnetic resonance images and subsequent importation of the combined images to a neuronavigation system (functional neuronavigation). METHODS: Six patients with brain lesions adjacent to the corticospinal tract (CST) were studied. During surgery, direct fiber stimulation was used to evoke motor responses to confirm the accuracy of CST depicted on functional neuronavigation. In three patients, stimulation of the supposed CST elicited the expected motor evoked potentials. In the other three, stimulation at the resection borders more than 1 cm away from the supposed CST showed no motor response. All patients underwent appropriate tumor resection with preservation of the CST. CONCLUSIONS: Integration of the DT imaging-based tractography information into a traditional neuronavigation system demonstrated spatial relationships between lesions and the CST, allowing for the avoidance of tract injury during lesion resection. Direct fiber stimulation was used for real-time reliable white matter mapping, which served to adjust for any discrepancy between the neuronavigation system data and potentially shifted positions of the brain structures. The combination of these techniques enabled the authors to identify accurate positions of the CST during surgery and to accomplish optimal tumor resections.

Adult↗

PubMed2004

[Distinguishing between occluded and low-flow vessels with PROPELLER DWI sequence: a phantom study].

PURPOSE: To evaluate the ability of periodically rotated overlapping parallel lines with enhanced reconstruction diffusion-weighted imaging (PROPELLER DWI) to distinguish between vessel occlusion and slow flow. MATERIALS AND METHODS: Using a flow phantom with various velocities (1.37 to 11.1 cm/s), the signal-intensity ratios of the phantom, with the intensity of no flow as baseline, were measured using the following imaging sequences: PROPELLER DWI, spin-echo T1-weighted imaging (SE T1WI), fast-spin-echo T2-weighted imaging (FSE T2WI), two-dimensional phase-contrast imaging (2D PC), and two-dimensional time-of-flight imaging (2D TOF). The b-factor of PROPELLER DWI was varied from 0 to 1000 s/mm(2). The velocity encoding of 2D PC was varied from 2 to 30 cm/s. RESULTS: At the lowest flow velocity (1.37 cm/s) , the signal-intensity ratio was 0.0075 for PROPELLER DWI (b-factor=1000 s/mm(2)), 1.8 for SE T1WI, 0.67 for FSE T2WI, 11 for 2D PC (velocity encoding=2 cm/s), and 1.4 for 2D TOF. The signal-intensity ratio was smallest for PROPELLER DWI, even when the reciprocals of the signal-intensity ratio of 2D PC or 2D TOF were considered. CONCLUSION: The results indicate that PROPELLER DWI provides the best signal intensity-ratio between vessel occlusion and slow flow. Although DWI with single-shot echo-planar imaging (EPI) or multi-shot EPI may have similarly high sensitivity for slow flow, these sequences do not have high spatial resolution or robustness to susceptibility artifacts. PROPELLER DWI would be a better choice for distinguishing between occluded and low-velocity arteries in the skull base or parasellar regions.

Blood Flow Velocity↗

PubMed2004

[Imaging characteristics of PROPELLER T2-weighted imaging].

As the PROPELLER sequence is a combination of the radial scan and fast-spin-echo (FSE) sequence, it can be considered an FSE sequence with a motion correlation. However, there are some differences between PROPELLER and FSE owing to differences in k-space trajectory. We clarified the imaging characteristics of PROPELLER T2-weighted imaging (T2WI) for different parameters in comparison with usual FSE T2WI. When the same parameters were used, PROPELLER T2WI showed a higher signal-to-noise ratio (SNR) and lower spatial resolution than usual FSE. Effective echo time (TE) changed with different echo train lengths (ETL) or different bandwidths on PROPELLER, and imaging contrast changed accordingly to be more effective.

Artifacts↗

PubMed2003

Aplasia of zygomatic arch and dislocation of temporomandibular joint capsule in Treacher-Collins syndrome: three-dimensional reconstruction of computed tomographic scans.

Seven patients with Treacher-Collins syndrome were studied. All of patients were children or teenagers. Helical CT scanner (Toshiba) was used to reconstruct zygomatic arch and temporomandibular joint capsule on lateral aspect of temporal bone in five patients of microtia and atresia of both ears and two patients of narrow ear canals of both ears without microtia.Three-dimensional reconstructions of computed tomography on lateral aspect of temporal bone demonstrated various congenital abnormality including aplasia of zygomatic arch in seven patients and dislocation of temporomandibular joint capsule in seven patients.

Adolescent↗