Publications by authors named "Aya M Tokumaru"
Purpose: These guidelines aim to support magnetic resonance imaging (MRI) diagnosis in patients receiving anti-amyloid β (Aβ) antibody treatment without restricting treatment eligibility.
Materials And Methods: These guidelines were collaboratively established by Japan Radiological Society, The Japanese Society of Neuroradiology, and Japanese Society for Magnetic Resonance in Medicine by reviewing existing literature and the results of clinical trials.
Results: Facility standards should comply with the "Optimal Use Promotion Guidelines" of Japan, and physicians should possess comprehensive knowledge of amyloid-related imaging abnormalities (ARIA) and expertise in brain MRI interpretation.
Background: Argyrophilic grain disease (AGD) is a four-repeat tauopathy characterized by the accumulation of argyrophilic grains. Its primary clinical manifestation is late-onset amnestic dementia. While the extension of argyrophilic grains to the substantia nigra may be related to its potential association with parkinsonism, biochemical analyses are lacking.
View Article and Find Full Text PDFPractical Brain MRI Guidelines for Anti-Aβ Antibody Treatment in Early Symptomatic Alzheimer's Disease.
Magn Reson Med Sci
April 2025
Purpose: These guidelines aim to support MRI diagnosis in patients receiving anti-amyloid β (Aβ) antibody treatment without restricting treatment eligibility.
Materials And Methods: These guidelines were collaboratively established by Japan Radiological Society, The Japanese Society of Neuroradiology, and Japanese Society for Magnetic Resonance in Medicine by reviewing existing literature and the results of clinical trials.
Results: Facility standards should comply with the "Optimal Use Promotion Guidelines" of Japan, and physicians should possess comprehensive knowledge of amyloid-related imaging abnormalities (ARIA) and expertise in brain MRI interpretation.
Diagnostic Challenge in Frontal Variant Alzheimer's Disease With Low Amyloid-β PET Retention.
Ann Clin Transl Neurol
July 2025
Diagnosing frontal variant Alzheimer's disease (fvAD) is difficult and could be even more difficult when amyloid-beta (Aβ) PET retention is low. A 63-year-old woman presenting with a 3-year history of apathy and memory impairment showed executive dysfunction, memory impairment, and severe bilateral frontotemporal atrophy on MRI. Aβ PET showed only equivocal findings in the right frontal lobe and was negative.
View Article and Find Full Text PDFSerum anti-IgLON5 antibodies, which were tested in 223 patients meeting the diagnostic criteria for progressive supranuclear palsy/corticobasal syndrome (PSP/CBS), were negative in all patients. Our study suggests that the frequency of anti-IgLON5 disease is extremely rare in patients with typical presentation of PSP/CBS.
View Article and Find Full Text PDFArticle Synopsis
- A case study focused on a 71-year-old woman with right temporal variant frontotemporal dementia (rtvFTD) revealed significant heading disorientation, showing that neurodegenerative diseases might impact spatial navigation differently than cerebrovascular diseases.
- Despite preserved general cognition, the patient struggled with familiar environments, unable to draw routes or maps, although she recognized landmarks; neuropsychological tests indicated specific heading disorientation related to her condition.
- Imaging studies (MRI and PET) showed notable abnormalities in the right hemisphere, especially in the retrosplenial region, which is linked to heading disorientation, and the patient’s symptoms worsened over time, which is distinct from prior observations with cerebrovascular cases.
Japanese longitudinal biomarker study in progressive supranuclear palsy and corticobasal degeneration: Clinical features of the first registered patients and short-term follow-up analysis.
Hiroshi Takigawa
,
Ritsuko Hanajima
,
Ikuko Aiba
,
Takayoshi Shimohata
,
Takahiko Tokuda
,
Aya M Tokumaru
Clin Park Relat Disord
October 2024
Article Synopsis
- A multicenter study in Japan began in 2014 to gather data on progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) to better understand their clinical features and identify potential biomarkers.
- Initial assessments of 349 patients focused on symptoms, clinical scores (like the PSPRS), and factors affecting disease progression over eight years.
- Results indicated that patients with Richardson's syndrome (RS) had better clinical scores compared to those with CBD, and cognitive dysfunction played a significant role in disease severity and progression.
Article Synopsis
- A 72-year-old man experienced a 6-month decline in voluntary speech marked by sparse speech and decreased word fluency, while other language abilities remained intact, indicating dynamic aphasia.
- Brain MRI showed left-sided white matter volume reduction in the frontal lobe, specifically affecting areas linked to speech production, and the patient's condition worsened over two years leading to complete mutism and death from aspiration pneumonia.
- The neuropathological diagnosis was corticobasal degeneration (CBD), suggesting that early signs of CBD may manifest as dynamic aphasia, potentially due to early involvement of certain brain pathways.
Article Synopsis
- - The study investigates how well conventional MRI can differentiate corticobasal degeneration (CBD) from its mimics due to similar clinical features.
- - Researchers analyzed the degree of brain atrophy and asymmetry in MRI images of 19 CBD patients and 16 patients with conditions that mimic CBD, like Alzheimer's and progressive supranuclear palsy.
- - Findings suggest that specific patterns of atrophy and the presence of white matter hyperintensity can be used as imaging biomarkers to help diagnose CBD more accurately.
Article Synopsis
- Argyrophilic grain disease (AGD) is linked to senile dementia, particularly cases where it is the sole pathological cause, also associated with parkinsonism.
- The study presents two autopsy cases of dementia with grains, highlighting distinct clinical features such as parkinsonism in one patient and pure amnestic dementia in another.
- Using cryo-electron microscopy, the researchers found a similar three-dimensional structure of tau protein in both cases and noted the presence of argyrophilic grains and tau structures in specific brain regions, suggesting a potential connection between AGD and parkinsonism.
Article Synopsis
- Corticobasal degeneration (CBD) presents a diverse clinical picture, making it challenging to predict its underlying pathology, which varies significantly among patients.
- A study examined 32 patients with confirmed CBD, highlighting that initial symptoms like gait disturbances often appeared quickly, while other issues such as cognitive impairment and dysphagia developed over the following years.
- The most common underlying pathologies included CBD itself, progressive supranuclear palsy, and Alzheimer's disease, with specific patterns of symptom development observed correlating to these conditions.
Article Synopsis
- Corticobasal syndrome (CBS) involves asymmetric symptoms due to issues in the cerebral cortex and basal ganglia, making early detection of imaging abnormalities difficult.
- Previous studies found asymmetric F-THK5351 PET abnormalities in CBS patients, but their effectiveness in larger early-stage groups needed further exploration.
- In a study of 15 CBS patients, 100% exhibited asymmetric tracer uptake on imaging, with F-THK5351 PET showing high sensitivity for identifying these abnormalities compared to other imaging techniques.
Article Synopsis
- CSF p-tau181 is a key biomarker for Alzheimer's disease (AD) and the study aimed to see if it changes in patients with Neuronal Intranuclear Inclusion Disease (NIID), a neurodegenerative disorder.
- The research compared CSF biomarker levels, including p-tau181, across 12 NIID patients, 120 confirmed AD patients, and various other neurocognitive disorder patients.
- Results showed significantly elevated CSF p-tau181 levels in NIID patients compared to others, indicating that NIID might share some biochemical features with AD despite the differences in other biomarkers like Aβ42.
Article Synopsis
- A 52-year-old woman developed Wallenberg syndrome after experiencing upper respiratory symptoms, leading to CT and MRI scans that showed nodular lesions in both her lungs and brain.
- A lung biopsy confirmed a diagnosis of low-grade lymphomatoid granulomatosis.
- PET scans indicated varying levels of tracer uptake, suggesting inflammation and reactive astrogliosis in the brain lesions, highlighting the importance of PET studies in understanding this condition's diagnosis and underlying mechanisms.
Article Synopsis
- Diffusion tensor imaging (DTI) can identify early changes in cerebral white matter integrity, linked to atherosclerosis and frailty in older adults.
- A longitudinal study followed outpatients with cardiometabolic diseases to explore the relation between baseline DTI metrics and frailty development over up to 6 years.
- Findings indicated that low fractional anisotropy (FA) and high mean diffusivity (MD) in white matter tracts, especially the anterior thalamic radiation (ATR), are associated with increased frailty risk, particularly in patients with diabetes mellitus.
Article Synopsis
- Neurodegenerative changes in the early stages of Alzheimer’s disease (AD) offer potential treatment possibilities, with a study of 134 elderly volunteers assessing cognitive impairment and amyloid deposition using neuroimaging techniques.
- Significant differences in brain atrophy were found in areas associated with AD, particularly in amyloid-positive participants, indicating more severe atrophy in regions like the bilateral parietal lobe and medial temporal areas.
- The analysis highlighted that amyloid-positive cognitively normal individuals showed greater differences in the size of their medial temporal areas compared to amyloid-negative participants, suggesting that even in the absence of cognitive decline, amyloid deposition can lead to measurable changes in brain structure.
Article Synopsis
- White matter abnormalities may be linked to cerebral microvessel disease, with diffusion tensor imaging (DTI) used to assess early changes in white matter integrity.
- The study analyzed 224 older patients (≥65 years) with cardiometabolic conditions, focusing on associations between cardiovascular risk factors (such as ankle brachial index and pulse wave velocity) and white matter changes through MRI assessments.
- Findings revealed that lower ankle brachial index (ABI) was consistently associated with white matter integrity abnormalities, while certain factors like high blood pressure and low body mass index also showed connections to these changes.
Article Synopsis
- Two patients with different forms of ALS underwent an 18F-THK5351 PET scan to examine areas of the brain affected by astrogliosis, which is related to disease progression.
- Patient 1 had flail leg syndrome, showing increased PET uptake in the motor cortex linked to the leg area.
- Patient 2, with ALS-frontotemporal dementia, displayed increased uptake in the left anterior temporal lobe, aligning with their neurological symptoms.
- This study suggests that 18F-THK5351 PET is an effective method for visualizing ALS-related brain lesions and understanding the disease's pathology.
Diffusion-Weighted Imaging is Key to Diagnosing Specific Diseases.
Magn Reson Imaging Clin N Am
May 2021
Article Synopsis
- The article focuses on diseases that can be diagnosed by persistent abnormalities seen in diffusion-weighted imaging.
- It summarizes the neuroimaging patterns for specific diseases, including sporadic Creutzfeldt-Jakob disease and others related to leukoencephalopathy.
- Additionally, it discusses differential diagnoses, clinical symptoms, and the pathologic, genetic, and imaging aspects related to these conditions.
Article Synopsis
- The study investigates the link between white matter hyperintensities (WMHs) and gait performance in older adults with varying degrees of cognitive impairment.
- It includes 150 participants divided into three groups: those with cognitive impairment, mild cognitive impairment, and cognitively normal, measuring factors like gait velocity and variability.
- Results revealed that greater WMHs correlated with slower gait and more variability in those with cognitive impairment, while those with mild impairment or normal cognition showed different patterns, highlighting the impact of cognitive levels on gait performance and neurological health.
Article Synopsis
- Voxel-based morphometry (VBM) analysis of MRI is used to detect medial temporal lobe (MTL) atrophy, which can help diagnose Alzheimer's disease, but its clinical reliability is unverified.
- A study compared VBM results with amyloid PET scans, revealing significant MTL atrophy in amyloid-positive patients, but substantial overlap between the two groups indicated issues with distinguishing them.
- While some differences were noted in Mini-Mental State Examination (MMSE) scores between groups, the ability of VBM to reliably differentiate between amyloid-positive and negative patients in clinical practice was limited, possibly due to overlapping symptoms with other dementia diseases.