Publications by authors named "Takeharu Yoshikawa"

Purpose: The prevalence of type 2 diabetes mellitus (T2DM) has been steadily increasing over the years. We aim to predict the occurrence of T2DM using mammography images within 5 years using two different methods and compare their performance.

Approach: We examined 312 samples, including 110 positive cases (developed T2DM after 5 years) and 202 negative cases (did not develop T2DM) using two different methods.

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A general-purpose method of emphasizing abnormal lesions in chest radiographs, named EGGPALE (Extrapolative, Generative and General-Purpose Abnormal Lesion Emphasizer), is presented. The proposed EGGPALE method is composed of a flow-based generative model and L-infinity-distance-based extrapolation in a latent space. The flow-based model is trained using only normal chest radiographs, and an invertible mapping function from the image space to the latent space is determined.

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  • * It was discovered that 73.7% of participants had minimal pleural fluid, with right-sided fluid being more common, and little change in fluid thickness was observed after a year.
  • * Factors like age, sex, smoking, body mass index, and blood pressure were linked to the presence of pleural fluid, which is typically considered physiological and shows variability based on individual characteristics.
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In this study, we investigated the application of distributed learning, including federated learning and cyclical weight transfer, in the development of computer-aided detection (CADe) software for (1) cerebral aneurysm detection in magnetic resonance (MR) angiography images and (2) brain metastasis detection in brain contrast-enhanced MR images. We used datasets collected from various institutions, scanner vendors, and magnetic field strengths for each target CADe software. We compared the performance of multiple strategies, including a centralized strategy, in which software development is conducted at a development institution after collecting de-identified data from multiple institutions.

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  • - The study explores the challenge of detecting small lung nodules, which are often missed in existing datasets, and introduces a novel cost function to improve training for detection networks by utilizing artificially created nodule images.
  • - Utilizing a modified U-Net architecture, the research effectively combines both positive (with nodules) and negative (without nodules) image pairs for training, aiming to reduce false positives and enhance detection accuracy.
  • - Results show that this new approach significantly outperformed existing detection models, providing promising sensitivity rates when tested on real clinical chest X-ray data, marking a notable advancement in lung nodule detection techniques.
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  • The study evaluated the performance of OpenAI's GPT-4 Turbo with Vision (GPT-4TV), which can process both text and images, against the text-only version (GPT-4 T) by using questions from the Japan Diagnostic Radiology Board Examination (JDRBE).
  • A dataset of 139 questions was analyzed, with certified radiologists providing expert answers and scoring the AI's responses for credibility.
  • Results showed that GPT-4TV answered slightly more questions correctly (45%) than GPT-4 T (41%), but this difference wasn't statistically significant, and GPT-4TV received lower legitimacy scores for its responses.
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Background And Purpose: The rise of large language models such as generative pretrained transformers (GPTs) has sparked considerable interest in radiology, especially in interpreting radiologic reports and image findings. While existing research has focused on GPTs estimating diagnoses from radiologic descriptions, exploring alternative diagnostic information sources is also crucial. This study introduces the use of GPTs (GPT-3.

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Purpose: The quality and bias of annotations by annotators (e.g., radiologists) affect the performance changes in computer-aided detection (CAD) software using machine learning.

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Objectives: To investigate the relationship between low kidney volume and subsequent estimated glomerular filtration rate (eGFR) decline in eGFR category G2 (60-89 mL/min/1.73 m) population.

Methods: In this retrospective study, we evaluated 5531 individuals with eGFR category G2 who underwent medical checkups at our institution between November 2006 and October 2017.

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  • Previous research on large language models (LLMs) in medicine focused mainly on text, but new multimodal LLMs, like GPT-4V, can now also interpret images.
  • This study evaluated GPT-4V's performance on visual questions from the Japanese National Medical Licensing Examination by testing its accuracy with and without images in 108 questions.
  • Results showed no significant difference in accuracy between the two conditions, indicating that the inclusion of images did not notably enhance GPT-4V's ability to answer the medical questions.
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  • The study aimed to create synthetic medical data by merging image and tabular data to improve patient outcome predictions using Covid-19 positive cases.
  • Researchers utilized chest X-ray images and clinical data from 1342 patients to develop a synthetic dataset through a series of encoding and generative modeling steps.
  • The utility of the synthetic dataset was validated via prediction models, showing an area under the curve (AUC) of 0.87 when combining real and synthetic data, indicating its effectiveness in generating useful medical records.
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Purpose: The purpose of this study was to investigate the longitudinal MRI characteristic of COVID-19-vaccination-related axillary lymphadenopathy by evaluating the size, T2-weighted signal intensity, and apparent diffusion coefficient (ADC) values.

Methods: COVID-19-vaccination-related axillary lymphadenopathy was observed in 90 of 433 health screening program participants on the chest region of whole-body axial MRIs in 2021, as reported in our previous study. Follow-up MRI was performed at an interval of approximately 1 year after the second vaccination dose from 2022 to 2023.

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Purpose: Standardized uptake values (SUVs) derived from F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography are a crucial parameter for identifying tumors or abnormalities in an organ. Moreover, exploring ways to improve the identification of tumors or abnormalities using a statistical measurement tool is important in clinical research. Therefore, we developed a fully automatic method to create a personally normalized Z-score map of the liver SUV.

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  • This study investigated the link between elevated thyroid-stimulating hormone (TSH) levels and the initial computed tomography (CT) density and volume of the thyroid gland in patients with new-onset hypothyroidism compared to a control group.
  • Results showed that patients with hypothyroidism had higher CT density and smaller thyroid volume at the start, and both features were associated with increased odds of developing hypothyroidism.
  • Over the study period, the hypothyroid group experienced a significant decrease in CT density, while the control group had a minor decrease, with thyroid volumes remaining stable in both groups.
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Mammography images contain a lot of information about not only the mammary glands but also the skin, adipose tissue, and stroma, which may reflect the risk of developing breast cancer. We aimed to establish a method to predict breast cancer risk using radiomics features of mammography images and to enable further examinations and prophylactic treatment to reduce breast cancer mortality. We used mammography images of 4000 women with breast cancer and 1000 healthy women from the 'starting point set' of the OPTIMAM dataset, a public dataset.

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The purpose of the study was to develop a liver nodule diagnostic method that accurately localizes and classifies focal liver lesions and identifies the specific liver segments in which they reside by integrating a liver segment division algorithm using a four-dimensional (4D) fully convolutional residual network (FC-ResNet) with a localization and classification model. We retrospectively collected data and divided 106 gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance examinations into Case-sets 1, 2, and 3. A liver segment division algorithm was developed using a 4D FC-ResNet and trained with semi-automatically created silver-standard annotations; performance was evaluated using manually created gold-standard annotations by calculating the Dice scores for each liver segment.

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Importance: Characterizing longitudinal patterns of regional brain volume changes in a population with normal cognition at the individual level could improve understanding of the brain aging process and may aid in the prevention of age-related neurodegenerative diseases.

Objective: To investigate age-related trajectories of the volumes and volume change rates of brain structures in participants without dementia.

Design, Setting, And Participants: This cohort study was conducted from November 1, 2006, to April 30, 2021, at a single academic health-checkup center among 653 individuals who participated in a health screening program with more than 10 years of serial visits.

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  • This study aimed to establish a standardized cut-off value for abnormal FDG accumulation in the thyroid gland using a large sample of FDG-PET/CT scans.
  • The research involved 7013 scans, utilizing automatic segmentation methods and categorizing results based on thyroid function linked to serum thyroid-stimulating hormone levels.
  • Findings revealed that a mean SUV ≥ 2 is strongly associated with thyroid dysfunction, with high sensitivity and specificity, indicating the potential for FDG-PET/CT to aid in thyroid evaluation.
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The purpose of this study was to realize an automated volume measurement of abdominal adipose tissue from the entire abdominal cavity in Dixon magnetic resonance (MR) images using deep learning. Our algorithm involves a combination of extraction of the abdominal cavity and body trunk regions using deep learning and extraction of a fat region based on automatic thresholding. To evaluate the proposed method, we calculated the Dice coefficient (DC) between the extracted regions using deep learning and labeled images.

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Background COVID-19 vaccination-related axillary lymphadenopathy has become an important problem in cancer imaging. Data are needed to update or support imaging guidelines for conducting appropriate follow-up. Purpose To investigate the prevalence, predisposing factors, and MRI characteristics of COVID-19 vaccination-related axillary lymphadenopathy.

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Purpose: The three-dimensional (3D) voxel labeling of lesions requires significant radiologists' effort in the development of computer-aided detection software. To reduce the time required for the 3D voxel labeling, we aimed to develop a generalized semiautomatic segmentation method based on deep learning via a data augmentation-based domain generalization framework. In this study, we investigated whether a generalized semiautomatic segmentation model trained using two types of lesion can segment previously unseen types of lesion.

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Background: It is essential for radiologists to communicate actionable findings to the referring clinicians reliably. Natural language processing (NLP) has been shown to help identify free-text radiology reports including actionable findings. However, the application of recent deep learning techniques to radiology reports, which can improve the detection performance, has not been thoroughly examined.

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Purpose: The performance of computer-aided detection (CAD) software depends on the quality and quantity of the dataset used for machine learning. If the data characteristics in development and practical use are different, the performance of CAD software degrades. In this study, we investigated changes in detection performance due to differences in training data for cerebral aneurysm detection software in head magnetic resonance angiography images.

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Purpose: Gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) has high diagnostic accuracy in the detection of liver lesions. There is a demand for computer-aided detection/diagnosis software for Gd-EOB-DTPA-enhanced MRI. We propose a deep learning-based method using one three-dimensional fully convolutional residual network (3D FC-ResNet) for liver segmentation and another 3D FC-ResNet for simultaneous detection and classification of a focal liver lesion in Gd-EOB-DTPA-enhanced MRI.

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Synopsis of recent research by authors named "Takeharu Yoshikawa"

  • - Takeharu Yoshikawa's recent research primarily focuses on the intersection of medical imaging and artificial intelligence, notably the development of advanced methodologies for lesion detection and diagnostics in radiology using machine learning and AI technologies, including federated learning approaches.
  • - The studies explore the effectiveness of artificial intelligence, particularly GPT models, in enhancing radiological diagnostics, with specific assessments on their performance in national examination contexts and their comparison against traditional methods.
  • - Yoshikawa's work also includes investigating clinical parameters, such as the impact of minimal pleural fluid and kidney volume on patient health outcomes, providing valuable insights into both diagnostic challenges and the integration of AI in radiological practices.