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Noriko Sato

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4 papers

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YNICL Journal 2018 Journal Article

Abnormal neurite density and orientation dispersion in unilateral temporal lobe epilepsy detected by advanced diffusion imaging

Daichi Sone
Noriko Sato
Miho Ota
Norihide Maikusa
Yukio Kimura
Hiroshi Matsuda

BACKGROUND: Despite recent advances in diffusion MRI (dMRI), there is still limited information on neurite orientation dispersion and density imaging (NODDI) in temporal lobe epilepsy (TLE). This study aimed to demonstrate neurite density and dispersion in TLE with and without hippocampal sclerosis (HS) using whole-brain voxel-wise analyses. MATERIAL AND METHODS: F-fluorodeoxyglucose positron emission tomography (FDG-PET)-positive patients (MRI-/PET+ TLE). The NODDI toolbox calculated the intracellular volume fraction (ICVF) and orientation dispersion index (ODI). Conventional dMRI metrics, that is, fractional anisotropy (FA) and mean diffusivity (MD), were also estimated. After spatial normalization, all dMRI parameters (ICVF, ODI, FA, and MD) of the patients were compared with those of age- and sex-matched healthy controls using Statistical Parametric Mapping 12 (SPM12). As a complementary analysis, we added an atlas-based region of interest (ROI) analysis of relevant white matter tracts using tract-based spatial statistics. RESULTS: We found decreased neurite density mainly in the ipsilateral temporal areas of both right and left TLE, with the right TLE showing more severe and widespread abnormalities. In addition, etiology-specific analyses revealed a localized reduction in ICVF (i.e., neurite density) in the ipsilateral temporal pole in MRI-/PET+ TLE, whereas TLE-HS presented greater abnormalities, including FA and MD, in addition to a localized hippocampal reduction in ODI. The results of the atlas-based ROI analysis were consistent with the results of the SPM12 analysis. CONCLUSION: NODDI may provide clinically relevant information as well as novel insights into the field of TLE. Particularly, in MRI-/PET+ TLE, neurite density imaging may have higher sensitivity than other dMRI parameters. The results may also contribute to better understanding of the pathophysiology of TLE with HS.

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YNICL Journal 2016 Journal Article

Automated subfield volumetric analysis of hippocampus in temporal lobe epilepsy using high-resolution T2-weighed MR imaging

Daichi Sone
Noriko Sato
Norihide Maikusa
Miho Ota
Kaoru Sumida
Kota Yokoyama
Yukio Kimura
Etsuko Imabayashi

BACKGROUND AND PURPOSE: Automated subfield volumetry of hippocampus is desirable for use in temporal lobe epilepsy (TLE), but its utility has not been established. Automatic segmentation of hippocampal subfields (ASHS) and the new version of FreeSurfer software (ver.6.0) using high-resolution T2-weighted MR imaging are candidates for this volumetry. The aim of this study was to evaluate hippocampal subfields in TLE patients using ASHS as well as the old and new versions of FreeSurfer. MATERIALS AND METHODS: We recruited 50 consecutive unilateral TLE patients including 25 with hippocampal sclerosis (TLE-HS) and 25 without obvious etiology (TLE-nonHS). All patients and 45 healthy controls underwent high-resolution T2-weighted and 3D-volume T1-weighted MRI scanning. We analyzed all of their MR images by FreeSurfer ver.5.3, ver.6.0 and ASHS. For each subfield, normalized z-scores were calculated and compared among groups. RESULTS: In TLE-HS groups, ASHS and FreeSurfer ver.6.0 revealed maximal z-scores in ipsilateral cornu ammonis (CA) 1, CA4 and dentate gyrus (DG), whereas in FreeSurfer ver.5.3 ipsilateral subiculum showed maximal z-scores. In TLE-nonHS group, there was no significant volume reduction by either ASHS or FreeSurfer. CONCLUSIONS: ASHS and the new version of FreeSurfer may have an advantage in compatibility with existing histopathological knowledge in TLE patients with HS compared to the old version of FreeSurfer (ver.5.3), although further investigations with pathological findings and/or surgical outcomes are desirable.

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YNICL Journal 2013 Journal Article

In vivo evaluation of gray and white matter volume loss in the parkinsonian variant of multiple system atrophy using SPM8 plus DARTEL for VBM

Yoko Shigemoto
Hiroshi Matsuda
Kouhei Kamiya
Norihide Maikusa
Yasuhiro Nakata
Kimiteru Ito
Miho Ota
Naofumi Matsunaga

In multiple system atrophy with predominant parkinsonism (MSA-P), several voxel-based morphometry (VBM) studies have revealed gray matter loss; however, the white matter volume changes have been rarely reported. We investigated the volume changes of white matter as well as gray matter by VBM. A retrospective MRI study was performed in 20 patients with MSA-P and 30 age-matched healthy controls. We applied VBM with statistical parametric mapping (SPM8) plus diffeomorphic anatomical registration through exponentiated Lie algebra (DARTEL) to explore the regional atrophy of gray and white matter in all of the MSA-P patients, 14 patients with left-side dominant and 6 patients with right-side dominant onset as compared to controls. In all of the MSA-P patients, VBM revealed a significant volume reduction of gray matter in the bilateral putamina, cerebellums and dorsal midbrain. White matter loss was located in bilateral globus pallidi, external capsules extending to the midbrain, right subcortical to precentral area through internal capsule, the pons, bilateral middle cerebellar peduncles and left cerebellum. In left-side dominant MSA-P patients, the gray and white matter volume loss was detected predominantly on the right side and vice versa in right-side dominant MSA-P patients. A correlation with disease duration and severity was not detected. VBM using SPM8 plus DARTEL detected significant volume loss not only in the gray but also in the white matter of the area affected by MSA-P.

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YNIMG Journal 2012 Journal Article

Daily physical complaints and hippocampal function: An fMRI study of pain modulation by anxiety

Motoharu Gondo
Yoshiya Moriguchi
Naoki Kodama
Noriko Sato
Nobuyuki Sudo
Chiharu Kubo
Gen Komaki

Pain is a popular physical complaint in human. It is known that experimental anxiety modulates pain processing through hippocampal amplification, whereas it is not known whether a similar experimental reaction is related to daily physical complaints known as ‘somatization’. The purpose of this study is to investigate the neural correlates of pain modulation induced by anxiety, particularly in the hippocampus, and how individual differences in this neural reaction relate to somatization. We measured neural response to noxious electrical stimulations, as well as the response to the preceding visual anticipatory cues (which induced low anxiety or high anxiety), by functional magnetic resonance imaging (fMRI). Individual daily physical symptoms were assessed by using the somatization subscale of the Symptom Checklist 90 revised (SCL-90-R). Correlation coefficients between the neural activations and the somatization scores were calculated. We found that manifestation of daily physical symptoms was related to smaller differences in hippocampus activation between high and low anxiety states, suggesting that the ability of the hippocampus to distinguish anxiety states was weakened by the chronic condition that caused the daily physical symptoms. The proper inhibition of neural activation in low anxiety states in the hippocampus and the anterior insula was observed to occur in companionship with lower daily physical complaints. These findings indicate that anxiety's alteration of the network that includes the hippocampus and that is associated with pain modulation underlies the manifestation of somatization.

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