Publications by authors named "Kamagata K"

The aging process induces a variety of changes in the brain detectable by magnetic resonance imaging (MRI). These changes include alterations in brain volume, fluid-attenuated inversion recovery (FLAIR) white matter hyperintense lesions, and variations in tissue properties such as relaxivity, myelin, iron content, neurite density, and other microstructures. Each MRI technique offers unique insights into the structural and compositional changes occurring in the brain due to normal aging or neurodegenerative diseases.

View Article and Find Full Text PDF

Ventricular tachycardia (VT) is a severe arrhythmia commonly treated with implantable cardioverter defibrillators, antiarrhythmic drugs and catheter ablation (CA). Although CA is effective in reducing recurrent VT, its impact on survival remains uncertain, especially in patients with extensive scarring. Stereotactic arrhythmia radioablation (STAR) has emerged as a novel treatment for VT in patients unresponsive to CA, leveraging techniques from stereotactic body radiation therapy used in cancer treatments.

View Article and Find Full Text PDF
Article Synopsis
  • - The study explores how the brain processes stopping behaviors when faced with external signals, focusing on the pathways involved in this response inhibition.
  • - Researchers utilized neuroimaging techniques and brain stimulation to map out a four-step processing pathway that starts from the visual cortex and moves through various brain regions before reaching motor control areas.
  • - Findings highlight the crucial roles of specific areas within the insular and prefrontal cortices, revealing how these regions communicate to efficiently inhibit responses, establishing a linked circuit: V1→daINS→vpIFC/aIFC→BG/M1.
View Article and Find Full Text PDF

This study included 52 Japanese older adults with Pittsburgh Sleep Quality Index (PSQI) scores > 5 and 52 healthy controls (HCs) with PSQI score ≤ 5. Diffusion-weighted imaging (DWI) and 3D T1-weighted imaging were acquired using 3T magnetic resonance imaging. The diffusion tensor image analysis along the perivascular space (DTI-ALPS) index was calculated using preprocessed DWI.

View Article and Find Full Text PDF

In this narrative review, we review the applications of artificial intelligence (AI) into clinical magnetic resonance imaging (MRI) exams, with a particular focus on Japan's contributions to this field. In the first part of the review, we introduce the various applications of AI in optimizing different aspects of the MRI process, including scan protocols, patient preparation, image acquisition, image reconstruction, and postprocessing techniques. Additionally, we examine AI's growing influence in clinical decision-making, particularly in areas such as segmentation, radiation therapy planning, and reporting assistance.

View Article and Find Full Text PDF

The integration of deep learning (DL) in breast MRI has revolutionized the field of medical imaging, notably enhancing diagnostic accuracy and efficiency. This review discusses the substantial influence of DL technologies across various facets of breast MRI, including image reconstruction, classification, object detection, segmentation, and prediction of clinical outcomes such as response to neoadjuvant chemotherapy and recurrence of breast cancer. Utilizing sophisticated models such as convolutional neural networks, recurrent neural networks, and generative adversarial networks, DL has improved image quality and precision, enabling more accurate differentiation between benign and malignant lesions and providing deeper insights into disease behavior and treatment responses.

View Article and Find Full Text PDF
Article Synopsis
  • Interventional oncology uses image-guided therapies like tumor embolization and ablation to treat malignant tumors minimally invasively, and AI is gaining traction in this field.
  • Recent literature shows a spike in studies exploring AI applications for tasks such as automatic segmentation, treatment simulation, and predicting treatment outcomes, with the latter being the most researched area.
  • Although many AI methods are still in the research phase and not widely used in clinical settings, the rapid advancements indicate that AI technologies will likely be integrated into interventional oncology practices soon.
View Article and Find Full Text PDF

A nucleoid protein Cren7 compacts DNA, contributing to the living of Crenarchaeum in high temperature environment. In this study, we investigated the dynamic behavior of Cren7 on DNA and its functional relation using single-molecule fluorescence microscopy. We found two mobility modes of Cren7, sliding along DNA and pausing on it, and the rapid dissociation kinetics from DNA.

View Article and Find Full Text PDF
Article Synopsis
  • * A study compared 50 poor sleepers and 50 good sleepers, revealing that poor sleepers had significantly lower myelin volume in key brain regions, which correlated with decreased cognitive function and increased depression.
  • * The findings suggest that circadian clock gene expression plays a role in these differences, with certain genes linked to regional variations in myelin content and overall brain health in relation to sleep quality.
View Article and Find Full Text PDF
Article Synopsis
  • - This review investigates the role of Large Language Models (LLMs) in nuclear medicine, particularly focusing on imaging techniques like PET and SPECT, highlighting recent advancements in both fields.
  • - It discusses current developments in nuclear medicine and how LLMs are being used in related areas like radiology for tasks such as report generation and image interpretation, with the potential to improve medical practices.
  • - Despite the promise of LLMs, challenges like reliability, explainability, and ethical concerns need to be addressed, making further research essential for integrating these technologies into nuclear medicine effectively.
View Article and Find Full Text PDF
Article Synopsis
  • Neuroimaging databases for neuro-psychiatric disorders provide valuable data for researchers to explore diseases, develop machine learning models, and redefine understanding of these conditions.* ! -
  • A review identified 42 global MRI datasets totaling 23,293 samples from patients with various disorders, including mood, developmental, schizophrenia, Parkinson's, and dementia.* ! -
  • Improved governance and addressing technical issues of these databases are essential for sharing data across borders, aiding in understanding, diagnosing, and creating early interventions for neuro-psychiatric disorders.* !
View Article and Find Full Text PDF
Article Synopsis
  • MRI is crucial for diagnosing pelvic issues related to organs like the prostate, bladder, and uterus, and uses RADS to standardize the process.
  • AI technologies, including machine learning, are being integrated into pelvic MRI to enhance various steps of diagnosis, especially for prostate imaging.
  • Recent multi-center studies highlight how AI can improve the effectiveness and reliability of pelvic MRI diagnostics by making findings more generalizable across different healthcare settings.
View Article and Find Full Text PDF

Background And Objectives: Integrating large language models (LLMs) such as GPT-4 Turbo into diagnostic imaging faces a significant challenge, with current misdiagnosis rates ranging from 30-50%. This study evaluates how prompt engineering and confidence thresholds can improve diagnostic accuracy in neuroradiology.

Methods: We analyze 751 neuroradiology cases from the American Journal of Neuroradiology using GPT-4 Turbo with customized prompts to improve diagnostic precision.

View Article and Find Full Text PDF
Article Synopsis
  • The study assessed the repeatability of T1 and T2* relaxation times and quantitative susceptibility (χ) values using quantitative parameter mapping (QPM) across three different 3T MRI scanners at three sites.
  • Twelve healthy volunteers underwent three separate scans at each site, and various statistical analyses were used to measure consistency and variation.
  • Results showed high intra-site repeatability for all measured values (T1, T2*, and χ) and acceptable cross-site reproducibility, suggesting QPM can reliably support multisite studies in MRI research.
View Article and Find Full Text PDF
Article Synopsis
  • A new deep learning-based method for brain segmentation (DLHBS) has been developed to accurately segment T1-weighted MRI scans into 107 brain subregions and calculate their volumes.
  • The method was trained on data from 486 subjects and tested for consistency in volume measurements using scans from 11 healthy subjects across three MRI scanners.
  • Results indicated that DLHBS outperformed traditional segmentation tools like SPM and FreeSurfer in terms of both repeatability and reproducibility for multiple brain regions.
View Article and Find Full Text PDF
Article Synopsis
  • Parkinson's disease (PD) is a progressive neurodegenerative disorder, and early biomarkers are needed for better diagnosis and understanding. This study focuses on analyzing the substantia nigra, an area affected in PD, using a new feature extraction method.
  • The researchers used images from 263 patients (124 PD and 139 non-PD) to test their method, which included training a model to classify differences in the substantia nigra between the two groups, achieving a sensitivity of 0.72 and specificity of 0.64.
  • Although the accuracy of the method is not yet on par with expert physicians, the study highlights the potential of using advanced tensorial feature extraction for diagnosing PD
View Article and Find Full Text PDF
Article Synopsis
  • * This review examines the environmental challenges associated with AI systems, such as greenhouse gas emissions from data centers and electronic waste, while also proposing solutions like energy-efficient models and renewable energy usage.
  • * It highlights the need for sustainable practices in AI deployment, suggesting policies, collaboration, and eco-friendly approaches, to ensure that AI advancements do not compromise environmental health.
View Article and Find Full Text PDF

Objective and background This study aimed to develop a deep convolutional neural network (DCNN) model capable of generating synthetic 4D magnetic resonance angiography (MRA) from 3D time-of-flight (TOF) images, allowing estimation of temporal changes in arterial flow. TOF MRA provides static information about arterial structures through maximum intensity projection (MIP) processing, but it does not capture the dynamic information of contrast agent circulation, which is lost during MIP processing. Considering the principles of TOF, it is hypothesized that dynamic information about arterial blood flow is latent within TOF signals.

View Article and Find Full Text PDF

Brain-computer interfaces (BCI) enable direct communication between the brain and a computer or other external devices. They can extend a person's degree of freedom by either strengthening or substituting the human peripheral working capacity. Moreover, their potential clinical applications in medical fields include rehabilitation, affective computing, communication, and control.

View Article and Find Full Text PDF

Moyamoya disease (MMD) causes cerebral arterial stenosis and hemodynamic disturbance, the latter of which may disrupt glymphatic system activity, the waste clearance system. We evaluated 46 adult patients with MMD and 33 age- and sex-matched controls using diffusivity along the perivascular space (ALPS) measured with diffusion tensor imaging (ALPS index), which may partly reflect glymphatic system activity, and multishell diffusion MRI to generate freewater maps. Twenty-three patients were also evaluated via O-gas positron emission tomography (PET), and all patients underwent cognitive tests.

View Article and Find Full Text PDF
Article Synopsis
  • Deep Learning (DL) has advanced diagnostic radiology by improving image analysis, and the introduction of Transformer architecture and Large Language Models (LLMs) has further transformed this area.* -
  • LLMs can streamline the radiology workflow, aiding in tasks like report generation and diagnostics, especially when combined with multimodal technology for enhanced applications.* -
  • However, challenges like information inaccuracies and biases remain, and radiologists need to understand these technologies better to maximize their benefits while ensuring medical safety and ethical standards.*
View Article and Find Full Text PDF

Cognitive dysfunction, especially memory impairment, is a typical clinical feature of long-term symptoms caused by repetitive mild traumatic brain injury (rmTBI). The current study aims to investigate the relationship between regional brain atrophy and cognitive impairments in retired athletes with a long history of rmTBI. Overall, 27 retired athletes with a history of rmTBI (18 boxers, 3 kickboxers, 2 wrestlers, and 4 others; rmTBI group) and 23 age/sex-matched healthy participants (control group) were enrolled.

View Article and Find Full Text PDF

Background And Purpose: Glymphatic system in type 2 diabetes mellitus (T2DM) but not in the prodrome, prediabetes (Pre-DM) was investigated using diffusion tensor image analysis along the perivascular space (DTI-ALPS). Association between glymphatic system and insulin resistance of prominent characteristic in T2DM and Pre-DM between is yet elucidated. Therefore, this study delves into the interstitial fluid dynamics using the DTI-ALPS in both Pre-DM and T2DM and association with insulin resistance.

View Article and Find Full Text PDF

Neuroinflammation contributes to the pathology and progression of Alzheimer's disease (AD), and it can be observed even with mild cognitive impairment (MCI), a prodromal phase of AD. Free water (FW) imaging estimates the extracellular water content and has been used to study neuroinflammation across several neurological diseases including AD. Recently, the role of gut microbiota has been implicated in the pathogenesis of AD.

View Article and Find Full Text PDF