Language：English   Publishing type：Research paper (scientific journal)  

Individuals with Prader-Willi syndrome (PWS) exhibit complex behavioral characteristics, including hyperphagia, autistic features, and subsequent age-related maladaptive behaviors. While this suggests functional involvements of subcortical, limbic, and brainstem areas, developmental abnormalities in such structures remain to be investigated systematically. Twenty-one Japanese individuals with PWS and 32 healthy controls with typical development were included. T1-weighted three-dimensional structural magnetic resonance images were analyzed for subcortical, limbic, and brainstem structural volumes, with age as a covariate, using a model-based automatic segmentation tool. Correlations were determined between each volume measurement and behavioral characteristics as indexed by questionnaires and block test scores for hyperphagia (HQ), autistic and obsessional traits, non-verbal intelligence (IQ), and maladaptive behavior (VABS_mal). Compared with the control group, the PWS group showed significantly reduced relative volume ratios per total intracranial volume (TIV) in thalamus, amygdala, and brainstem structures, along with TIV and native volumes in all substructures. While the brainstem volume ratio was significantly lower in all age ranges, amygdala volume ratios were significantly lower during early adulthood and negatively correlated to HQ and VABS_mal but positively correlated to Kohs IQ. Thus, limbic and brainstem volume alterations and differential volume trajectories may contribute to the developmental and behavioral pathophysiology of PWS.

DOI： 10.1038/s41598-022-08898-3

PubMed

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

DOI： 10.1016/j.bionps.2021.100039

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

The glycine level in the brain is known to be altered in neuropsychiatric disorders, such as schizophrenia and Alzheimer's disease (AD). Several studies have reported the in vivo measurement of glycine concentrations in the brain using proton magnetic resonance spectroscopy (1H-MRS), but 1H-MRS is not capable of imaging the distribution of glycine concentration with high spatial resolution. Chemical exchange saturation transfer magnetic resonance imaging (CEST-MRI) is a new technology that can detect specific molecules, including amino acids, in tissues. To validate the measurements of glycine concentrations in living tissues using CEST from glycine to water (GlyCEST), we extracted the brain tissues from mice and performed biochemical tests. In wild-type C57BL/6 mice, GlyCEST effects were found to be higher in the thalamus than in the cerebral cortex (P < 0.0001, paired t-test), and this result was in good agreement with the biochemical results. In 5xFAD mice, an animal model of AD, GlyCEST measurements demonstrated that glycine concentrations in the cerebral cortex (P < 0.05, unpaired t-test) and thalamus (P < 0.0001, unpaired t-test), but not in the hippocampus, were decreased compared to those in wild-type mice. These findings suggest that we have successfully applied the CEST-MRI technique to map the distribution of glycine concentrations in the murine brain. The present method also captured the changes in cerebral glycine concentrations in mice with AD. Imaging the distribution of glycine concentrations in the brain can be useful in investigating and elucidating the pathological mechanisms of neuropsychiatric disorders.

DOI： 10.1155/2021/8988762

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Ultra-high field magnetic resonance imaging (MRI) has been introduced for use in pediatric developmental neurology. While higher magnetic fields have certain advantages, optimized techniques with specific considerations are required to ensure rational and safe use in children and those with pediatric neurological disorders (PNDs). Here, we summarize our initial experience with clinical translational studies that utilized 7 tesla (T)-MRI in the fields of developmental neurology. T2-reversed images and three-dimensional anisotropy contrast imaging enabled the depiction of targeted pathological brain structures with better spatial resolution. Diffusion imaging and susceptibility-weighted imaging enabled visualization of intracortical, subcortical, and intratumoral microstructures in vivo within highly limited scan times appropriate for patients with PNDs. 7T-MRI appears to have significant potential to enhance the depiction of the structural and functional properties of the brain, particularly those associated with atypical brain development.

DOI： 10.25259/JCIS_185_2021

PubMed

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.ecns.2020.07.002

researchmap

Language：Japanese   Publisher：(一社)日本小児神経学会  

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

The objective of this study was to investigate lobule-specific cerebellar structural alterations relevant to clinical behavioral characteristics of Prader-Willi syndrome (PWS). We performed a case-control study of 21 Japanese individuals with PWS (age; median 21.0, range 13-50 years, 14 males, 7 females) and 40 age- and sex-matched healthy controls with typical development. Participants underwent 3-Tesla magnetic resonance imaging. Three-dimensional T1-weighted images were assessed for cerebellar lobular volume and adjusted for total intracerebellar volume (TIV) using a spatially unbiased atlas template to give a relative volume ratio. A region of interest analysis included the deep cerebellar nuclei. A correlation analysis was performed between the volumetric data and the clinical behavioral scores derived from the standard questionnaires (hyperphagia, autism, obsession, and maladaptive index) for global intelligence assessment in paired subgroups. In individuals with PWS, TIV was significantly reduced compared with that of controls (p < 0.05, family-wise error corrected; mean [standard deviation], 1014.1 [93.0] mm3). Decreased relative lobular volume ratios were observed in posterior inferior lobules with age, sex, and TIV as covariates (Crus I, Crus II, lobules VIIb, VIIIa, VIIIb, and IX). However, increased ratios were found in the dentate nuclei bilaterally in individuals with PWS (p < 0.01); the mean (standard deviation) × 10-3 was as follows: left, 1.58 (0.26); right, 1.67 (0.30). The altered lobular volume ratios showed negative correlations with hyperphagic and autistic characteristics and positive correlations with obsessive and intellectual characteristics. This study provides the first objective evidence of topographic patterns of volume differences in cerebellar structures consistent with clinical behavioral characteristics in individuals with PWS and strongly suggests a cerebellar contribution to altered functional brain connectivity in PWS.

DOI： 10.1007/s12311-020-01163-1

PubMed

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Informa UK Limited  

DOI： 10.1080/01616412.2018.1522413

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Society for Medical and Biological Engineering  

DOI： 10.14326/abe.7.156

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE INC  

Purpose: To perform a systematic analysis of the intrinsic contrast parameters of the FLAIR hyperintense rim (FHR), a thin layer of high intensity covering the entire surface of the cerebral cortex detected on fluid-attenuated inversion recovery (FLAIR) sequence T-2 weighted imaging performed on a 7T system, in an attempt to identify its anatomical correlate.
Methods: Fast spin echo inversion recovery (FSE-IR) and cardiac-gated fast spin echo (FSE) images were obtained with defined parameters in eight normal volunteers on a 7 T MRI system to determine T-2 and proton density, T-1 characteristics. K-means clustering analysis of parameter sets was performed using MATLAB version R2015b for the purpose of identifying the cluster reflecting FHR. The results were subsequently confirmed by independent component analysis (ICA) based on Ti behavior on FSE-IR using a MATLAB script of FastICA algorithm.
Results: The structure giving rise to FHR was found to have a unique combination of intrinsic contrast parameters of low proton density, long T-2, and disproportionally short T-5. The findings are in strong agreement with the functional and structural specifics of the glia limitans externa (GLE), a structure composed of snuggled endfeet of astrocytes containing abundant aquaporin-4 (AQP-4), the main water channel of the brain.
Conclusion: Intrinsic contrast parameters of FHR reflect structural and functional specifics of the GLE, and their values are highly dependent on the physiologic functionality of AQP-4. Microscopic imaging on a 7T system and analysis of GLE contrast parameters can be developed into a method for evaluating AQP-4 functionality.

DOI： 10.1016/j.mri.2017.08.012

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

BACKGROUND: The aim of the present study was to investigate maturational changes in glutamate (Glu) in the human cerebral cortex from childhood to young adulthood using 3.0-Tesla proton magnetic resonance spectroscopy (H-1-MRS), which is capable of quantifying Glu in vivo.
METHODS: Normal volunteers comprising 11 children (aged 4-13 years) and 11 young adults (aged 18-33 years) participated in the study. Single-voxel point-resolved spectroscopy (PRESS, repetition time/echo time = 2,000/80 ms) was performed on the frontal and occipital cortices, and the Glu-to-creatine ratio (Glu/Cr) and N-acetylaspartate-to-creatine ratio (NAA/Cr) were determined.
RESULTS: In both the frontal and occipital cortices, Glu/Cr was significantly lower during young adulthood relative to that during childhood. NAA/Cr did not differ significantly between the two age groups.
CONCLUSION: This study has provided objective evidence that cerebral cortical Glu/Cr decreases between childhood and young adulthood. The observed decrease in Glu/Cr may reflect the simultaneous occurrence of maturational changes, such as changes in cortical microstructure and the intercellular compartmentation of Glu metabolism.

DOI： 10.1038/pr.2017.101

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Society for Neuroscience  

The neural processes underlying self-initiated behavior (behavior that is initiated without an external stimulus trigger) are not well understood. This event-related fMRI study investigated the neural origins of self-initiated behaviors in humans, by identifying brain regions that increased in neural activities several seconds prior to self-initiated movements. Subjects performed a hand grasping task under two conditions: a free-timing and cued timing condition. The supplementary motor area (SMA) began to activate several seconds prior to self-initiated movement (accounting for hemodynamic delay), representing a potential blood oxygenation level-dependent (BOLD) signal correlate of the readiness potential (RP) on electroencephalogram (EEG), referred to here as “readiness BOLD signals.” Significant readiness BOLD signals were also observed in the right frontoparietal areas, precuneus, and insula, all of which are known to contribute to internally-generated behaviors, but with no prior evidence for such early and slow accumulation of neural activities. Moreover, visual and auditory cortices also exhibited clear readiness BOLD signals with similar early onsets, even absent external stimulation. Slow accumulation of neural activities throughout distributed cortical areas, including sensory, association, and motor cortices, underlies the generation of self-initiated behaviors. These findings warrant reconsideration of the prevailing view that the SMA or some other specific locus in frontoparietal cortex serves as the ultimate neural origin of self-initiated movement.

DOI： 10.1523/ENEURO.0183-17.2017

Scopus

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE INC  

Objective. Magnetic resonance neurography reveals abnormal morphologies of regenerated nerves and overgrown connective tissue in injured trigeminal nerves, suggesting neuroma formation. We hypothesized that such deformities and scar formation contribute to pain symptoms.
Study Design. High-contrast high-resolution magnetic resonance imaging was utilized to evaluate the inferior alveolar nerve and lingual nerve following traumatic injury in 19 patients. The relationship between the morphologic classification and severity of the sensory disorder was assessed.
Results. In all cases, 3-dimensional anisotropy contrast periodically rotated overlapping parallel lines with enhanced reconstruction (3DAC-PROPELLER) successfully revealed the inner structures within the lesion. The isolated type represented the normal course of the nerve isolated from scar-like tissue (8 cases), whereas the deformity type included the deformed nerve either within scar-like tissue or by itself, unassociated with surrounding scar-like tissue (9 cases). In the remaining 2 cases, the nerve tissue and scar-like tissue were incorporated. Patients with the deformity type exhibited significantly more severe pain symptoms compared with patients with the isolated type.
Conclusions. Overgrown connective tissue does not necessarily block regenerating nerves and itself may not cause pain. The morphologic findings on the 3DAC-PROPELLER were relevant to the severity of pain symptoms.

DOI： 10.1016/j.oooo.2017.02.017

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier B.V.  

DOI： 10.1016/j.ensci.2016.10.002

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

BACKGROUND AND PURPOSE: Presence of an intimal flap is a critical imaging finding in diagnosing intracranial artery dissection (ICAD). Recent reports showed that high-resolution magnetic resonance imaging (MRI) was better at identifying intimal flaps as compared with routine MRI techniques used in clinical settings. However, no current standardized sequence for high-resolution MRI without gadolinium enhancement produces images of satisfactory quality with clinically tolerable scanning times. This study evaluated a nonenhanced high-resolution fast spin echo (HR-FSE) MRI sequence for visualizing intimal flaps in patients with ICAD.
SUBJECTS AND METHODS: Three patients with ICAD underwent plain MRI examination using a 2-dimensional T2-weighted FSE imaging sequence optimized for our 3T system (in-plane pixel size, .23 mm x .23 mm; slice thickness 3 mm with no interslice gap), as well as scanning with conventional modalities, including CT angiography, magnetic resonance angiography, and digital subtraction angiography. We assessed whether these imaging methods could visualize an intimal flap and/or double lumen sign in the participants and compared the results between HR-FSE and the other modalities.
RESULTS: HR-FSE images clearly showed intimal flaps and double lumen signs in all 3 patients, whereas the conventional modalities identified a double lumen sign in only 2 of the 3 patients.
CONCLUSIONS: The present method of optimized HR-FSE imaging with a 3T system improved visualization of intimal flaps and should thus be considered for assessing patients with suspected ICAD that cannot be definitively diagnosed by conventional imaging modalities.

DOI： 10.1111/jon.12380

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier Inc  

Cerebral venous sinus thrombosis (CVST) is an uncommon form of stroke, and mortality of the acute phase is high. We report the clinical, postmortem 3 T-MRI, and autopsy features of a patient, 20-year-old Japanese woman, with CVST who died shortly after starting to use low-dose estrogen combined hormonal contraceptives (CHCs). A postmortem 3 T-MRI study with our originally developed system revealed abnormal intensities suggestive of thrombi extending throughout the straight sinus and left sigmoid sinus. At autopsy, in accordance with the images, we performed careful preparations of the sinuses. Histological examination revealed an organizing white thrombus occupying the lumen of the left sigmoid sinus, and an acute, red thrombus in the lumen of the left transverse, straight, and tentorial sinuses, and vein of Galen, indicating that the thrombus had developed first in the left sigmoid sinus, then extended retrogradely to the more proximal portion of the sinus system, reaching the vein of Galen. The features of the present CVST patient appear to be informative, when encountering CHC users with neurological symptoms, even in those who begun to use low-dose estrogen CHCs only recently.

DOI： 10.1016/j.ehpc.2016.01.002

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：KARGER  

Background: In patients with cerebral infarction, identifying the distribution of infarction and the relevant artery is essential for ascertaining the underlying vascular pathophysiological mechanisms and preventing subsequent stroke. However, visualization of the basal perforating arteries (BPAs) has had limited success, and simultaneous viewing of background anatomical structures has only rarely been attempted in living human brains. Our study aimed at identifying the BPAs with 7T MRI and evaluating their distribution in the subcortical structures, thereby showing the clinical significance of the technique. Methods: Twenty healthy subjects and 1 patient with cerebral infarction involving the posterior limb of the internal capsule (ICpost) and thalamus underwent 3-dimensional fast spoiled gradient-echo sequence as time-of-flight magnetic resonance angiography (MRA) at 7T with a submillimeter resolution. The MRA was modified to detect inflow signals from BPAs, while preserving the background anatomical signals. BPA stems and branches in the subcortical structures and their origins were identified on images, using partial maximum intensity projection in 3 dimensions. Results: A branch of the left posterior cerebral artery (PCA) in the patient ran through both the infarcted thalamus and ICpost and was clearly the relevant artery. In 40 intact hemispheres in healthy subjects, 571 stems and 1,421 branches of BPAs were detected in the subcortical structures. No significant differences in the numbers of stems and branches were observed between the intact hemispheres. The numbers deviated even less across subjects. The distribution analysis showed that the subcortical structures of the telencephalon, such as the caudate nucleus, anterior limb of the internal capsule, and lenticular nucleus, were predominantly supplied by BPAs from the anterior circulation. In contrast, the thalamus, belonging to the diencephalon, was mostly fed by BPAs from the posterior circulation. However, compared with other subcortical structures, the ICpost, which marks the anatomical boundary between the telencephalon and the diencephalon, was supplied by BPAs with significantly more diverse origins. These BPAs originated from the internal carotid artery (23.1%), middle cerebral artery (38.5%), PCA (17.3%), and the posterior communicating artery (21.1%). Conclusions: The modified MRI method allowed the detection of the relevant BPA within the infarcted in the stroke survivor as well as the BPAs in the subcortical structures of living human brains. Based on in vivo BPA distribution analyses, the ICpost is the transitional zone of the anterior and posterior cerebral circulations. (C) 2016 S. Karger AG, Basel

DOI： 10.1159/000443538

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

BACKGROUND AND PURPOSE
An important task in diagnostic imaging of acute ischemic stroke is to identify the so-called diffusion-perfusion mismatch area. We aimed to investigate the possibility of facilitating the identification process by combining independent component analysis (ICA) and diffusion-weighted MRI (DWI), with the expectation that this would eliminate the need for additional perfusion imaging to delineate perfusion lesion.
METHODS
Simulations were performed to confirm the utility of an intuitively determined sequence of 14 b-factors ranging from 0 to 1,000 seconds/mm(2) for ICA separation of perfusion lesion. Corresponding DWI data from 2 stroke patients, 1 in the acute and 1 in the subacute phase, were decomposed into independent component (IC) maps, and their b-dependent amplitude decay profiles were subjected to multiexponential fitting.
RESULTS
Low-perfusion areas were successfully delineated on IC maps in both patients. Comparison with the areas of diffusion lesion identifiable on relatively high b-factor images in the DWI data, for example, those at b = 1,000 seconds/mm(2), allowed the mismatch to be identified.
CONCLUSION
This study demonstrates that combining ICA and DWI enables noninvasive mapping of sluggish perfusion provided an appropriate b-sequence is applied, and that it thereby facilitates the identification of diffusion-perfusion mismatch.

DOI： 10.1111/j.1552-6569.2010.00514.x

Web of Science

PubMed

researchmap

J-GLOBAL

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

We herein report a rare case of cerebellopontine angle (CPA) medulloblastoma originating in the brainstem that demonstrated a very unusual clinical presentation and radiological appearances. A 25-year-old female was admitted to our hospital with a right hearing disturbance and a right facial palsy. A small non-enhanced lesion having minimal mass effect in the right CPA was identified by using a 1.5-tesla-MR system, whose size remained almost unchanged a year. The 3-tesla MR images revealed that the precise region was in the right side of the tegmentum of the lower pons to the inferior cerebellar peduncle and the flocculus. MR spectroscopic images using a 3-tesla system revealed a high ratio of choline-to-N-acetylaspartate in the region of interest in comparison to the contra-lateral side. Craniotomy and biopsy were performed. The histopathological diagnosis was medulloblastoma. The patient received craniospinal irradiation and chemotherapy, and achieved complete remission by the time of the follow-up MR images. She is now doing well with a full recovery of the right facial palsy. MR spectroscopic imaging is considered to be quite useful for the management of this rare type of brainstem tumor.

DOI： 10.1111/j.1552-6569.2008.00298.x

PubMed

researchmap

Language：Japanese  

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER WIEN  

Background. Placement of detachable coil(s) for intracranial aneurysms has become one of the standard methods of management. Although detailed analysis of post-procedure changes in aneurysmal lumen is essential, technical difficulties often limit such evaluation. Development of higher magnetic field systems is steadily widening clinical usage of magnetic resonance imaging (MRI) primarily due to its significantly higher signal to noise ratio.
Objective. In this study, we evaluated a multi-planar reconstruction (MPR) technique of magnetic resonance angiography (MRA) on a 3.0T system in an attempt to develop a routine method of post-procedure evaluation following detachable coil placement.
Methods. Eleven patients with an intracranial aneurysm following placement of a Guglielmi detachable coil (GDC) participated in the study. Time of flight (TOF) magnetic resonance angiography (MRA) was obtained immediately after, and up to two years after coil embolisation utilising a GE 3.0T system. Data was analysed using standard maximum intensity projection (MIP) as well as the MPR technique and the results were compared to conventional catheter angiography.
Results. The study demonstrated that, compared to MIP, MPR can provide further information of alteration in aneurysm lumen, especially in analysis of: 1) jet of blood flow, 2) thrombus formation, 3) neck remnant or re-filling of blood, 4) location and shape of coils including compaction, and 5) coil protrusion into the parent artery.
Conclusions. Combined MPR/MIP analysis of high-field MRA appears to be a powerful non-invasive method for evaluating GDC-treatment that can potentially replace conventional catheter angiography in many clinical situations.

DOI： 10.1007/s00701-008-1418-4

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japanese Society for Magnetic Resonance in Medicine  

Dynamic contrast enhanced magnetic resonance imaging (dynamic MRI) represents a MRI version of <i>non-diffusible</i> tracer methods, the main clinical use of which is the physiological construction of what is conventionally referred to as perfusion images. The raw data utilized for constructing MRI perfusion images are time series of pixel signal alterations associated with the passage of a gadolinium containing contrast agent. Such time series are highly compatible with independent component analysis (ICA), a novel statistical signal processing technique capable of effectively separating a single mixture of multiple signals into their original independent source signals (blind separation). Accordingly, we applied ICA to dynamic MRI time series. The technique was found to be powerful, allowing for hitherto unobtainable assessment of regional cerebral hemodynamics <i>in vivo</i>.<br>

DOI： 10.2463/mrms.2.23

CiNii Article

CiNii Books

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2463/mrms.1.165

Scopus

PubMed

researchmap

researchmap

Language：Japanese   Publisher：日本基礎心理学会  

researchmap

researchmap

researchmap

researchmap

Language：Japanese   Publisher：(株)インナービジョン  

新潟大学脳研究所は、脳神経外科と神経内科の臨床2科、神経病理部門、そして統合脳機能研究センターなどを有している。同センターの中田力名誉教授(当時・教授/センター長)の発案により実現した、3T MRIを用いた死後画像解析システムが稼働している。われわれのポリシーは、死亡時画像診断(以下、Ai)施行後直ちに病理解剖を行い、画像情報と組織所見を統合して病態理解につなげようとするものである。Aiを剖検の代替手段として行おうとするものではない。本稿では、神経疾患を対象として当研究所が取り組んでいる死後画像解析システムと病理解剖について紹介する。(著者抄録)

researchmap

Language：Japanese   Publisher：(NPO)日本脳神経血管内治療学会  

researchmap

Language：Japanese   Publisher：日本末梢神経学会  

三叉神経の神経障害性疼痛に対して、病変神経切除部位に人工神経PGA-C tubeを設置して神経再生を促す生体内再生治療はすでに臨床応用されている。患者で実際にどのように神経が再生されているのかを高分解能MRIにより検索した。再生神経の形態は、正常な解剖学的形態(2例)、正常形態であるが菲薄化(2例)、変形して再生、このうち変形には術前と同形態(3例)と異なる形態(2例)に分類された。正常もしくは菲薄化群は、症状と疼痛管理の改善度が、何らかの変形群に比し良好な傾向であった。再生神経の変形は正常な神経再生とは異なる再生過程による組織を反映したものと考えられる。(著者抄録)

researchmap

Language：Japanese   Publisher：法医病理研究会  

researchmap