Hidetaka Nambo

Prof. Hidetaka Nambo

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Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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11 July 2022 in PLOS ONE
Verified
Journal Article
Open access
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SHSatoshi Hara
Satoshi Hara
EHEmi Haneda
Emi Haneda
MKMasaki Kawakami
Masaki Kawakami
KMKento Morita
Kento Morita
RNRyo Nishioka
Ryo Nishioka
HNHidetaka Nambo
Hidetaka Nambo
Renal pathology is essential for diagnosing and assessing the severity and prognosis of kidney diseases. Deep learning-based approaches have developed rapidly and have been applied in renal pathology. However, methods for the automated classification of normal and abnormal renal tubules remain scarce. Using a deep learning-based method, we aimed to classify normal and abnormal renal tubules, thereby assisting renal pathologists in the evaluation of renal biopsy specimens. Consequently, we developed a U-Net-based segmentation model using randomly selected regions obtained from 21 renal biopsy specimens. Further, we verified its performance in multiclass segmentation by calculating the Dice coefficients (DCs). We used 15 cases of tubulointerstitial nephritis to assess its applicability in aiding routine diagnoses conducted by renal pathologists and calculated the agreement ratio between diagnoses conducted by two renal pathologists and the time taken for evaluation. We also determined whether such diagnoses were improved when the output of segmentation was considered. The glomeruli and interstitium had the highest DCs, whereas the normal and abnormal renal tubules had intermediate DCs. Following the detailed evaluation of the tubulointerstitial compartments, the proximal, distal, atrophied, and degenerated tubules had intermediate DCs, whereas the arteries and inflamed tubules had low DCs. The annotation and output areas involving normal and abnormal tubules were strongly correlated in each class. The pathological concordance for the glomerular count, t, ct, and ci scores of the Banff classification of renal allograft pathology remained high with or without the segmented images. However, in terms of time consumption, the quantitative assessment of tubulitis, tubular atrophy, degenerated tubules, and the interstitium was improved significantly when renal pathologists considered the segmentation output. Deep learning algorithms can assist renal pathologists in the classification of normal and abnormal tubules in renal biopsy specimens, thereby facilitating the enhancement of renal pathology and ensuring appropriate clinical decisions.

30 June 2025 in IEEE Access
Verified
Journal Article
Open access
RPRizal Dwi Prayogo
Rizal Dwi Prayogo
Nur HamidNur Hamid
Nur Hamid
HNHidetaka Nambo
Hidetaka Nambo
Brain tumors are among the deadliest diseases worldwide and require early and accurate diagnosis via Magnetic Resonance Image (MRI). Deep learning techniques, particularly convolutional neural networks (CNNs), have been widely adopted for analyzing brain MRI images in tumor classification tasks. However, individual models of conventional CNNs often struggle with tumor diversity due to their restricted receptive fields and homogeneous feature extraction, leading to suboptimal diagnostic precision.We propose a hybrid transfer learning framework based on CNN architectures for enhanced multiclass brain tumor classification. A publicly accessible brain MRI dataset from Kaggle is employed in this study. The dataset, constructed from Figshare, SARTAJ, and Br35H, contains 7023 original images categorized into four classes: glioma, meningioma, pituitary, and no tumor.We introduce a preprocessing pipeline involving MRI cropping and affine-based augmentation to balance a strategically modified version of our dataset, which includes intentional class imbalance. Leveraging transfer learning, we fine-tune lightweight pre-trained models such as ResNet50V2, MobileNetV2, DenseNet121, EfficientNetV2S, and NASNetMobile and adopt a hybrid feature extraction strategy that integrates multilevel feature maps. Experimental evaluations reveal that our hybrid model (ResNet50V2 + MobileNetV2 + DenseNet121) achieves superior performance, attaining 98.75% accuracy, 98.76% precision, 98.75% recall, and 98.75% F1-score, outperforming individual models and state-of-the-art methods. The results highlight that integrating diverse features from multiple CNNs enhances classification robustness by capturing complementary tumor characteristics. In conclusion, our study advances medical imaging diagnostics by demonstrating the efficacy of hybrid transfer learning in overcoming data imbalance and model limitations, offering a reliable tool for clinical decision-making.

16 November 2023 in Journal of Reliable Intelligent Environments
Verified
Journal Article
Open access
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WDWilly Dharmawan
Willy Dharmawan
MDMery Diana
Mery Diana
BTBeti Tuntari
Beti Tuntari
IAI. Made Astawa
I. Made Astawa
SRSasono Rahardjo
Sasono Rahardjo
HNHidetaka Nambo
Hidetaka Nambo
Near-field tides prediction for tsunami detection in the coastal area is a significant problem of the cable-based tsunami meter system in north Sipora, Indonesia. The problem is caused by its shallow water condition and the unavailability of an applicable model or research for tsunami detection in this area. The problem foundation of shallow water area is its ambient noise level-dependent property that requires preprocessing to improve its feature representation. Moreover, because this shallow water is close to the land area, we must consider a model that can accommodate low prediction time for a Tsunami Early Warning System. Therefore, we propose a recurrent neural network (RNN) model because of its reliable performance for time series forecasting. Our report evaluates variants of the RNN model (the vanilla RNN, LSTM and GRU models) in tides prediction and z-score analysis for tsunami identification. The GRU model overwhelms the other two variants in error scores and time processed (training and prediction). It can achieve median error score distribution of $$7.8 \times 10^{-5}$$ 7.8 × 10 - 5 on the L1000-P250 configuration with time prediction under 0.1 s. This lower-time prediction is necessary to ensure the early warning system is going well. Moreover, the GRU model can identify all synthetic tsunami tide spikes (compared with the ground truth result) from magnitude 7.2–8.2 by applying a z-score on the GRU’s prediction.

8 March 2024 in Journal of Medical Systems
Verified
Journal Article
Closed access
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KMKento Morita
Kento Morita
SKShigehiro Karashima
Shigehiro Karashima
TTToshiki Terao
Toshiki Terao
KYKotaro Yoshida
Kotaro Yoshida
TYTakeshi Yamashita
Takeshi Yamashita
Hiroyuki TakamatsuHiroyuki Takamatsu
Hiroyuki Takamatsu

7 May 2024 in Scientific Reports
Verified
Journal Article
Open access
PDF file
RNRiku Nambo
Riku Nambo
SKShigehiro Karashima
Shigehiro Karashima
RMRen Mizoguchi
Ren Mizoguchi
SKSeigo Konishi
Seigo Konishi
AHAtsushi Hashimoto
Atsushi Hashimoto
HNHidetaka Nambo
Hidetaka Nambo
Cardiovascular and cerebrovascular diseases (CCVD) are prominent mortality causes in Japan, necessitating effective preventative measures, early diagnosis, and treatment to mitigate their impact. A diagnostic model was developed to identify patients with ischemic heart disease (IHD), stroke, or both, using specific health examination data. Lifestyle habits affecting CCVD development were analyzed using five causal inference methods. This study included 473,734 patients aged ≥ 40 years who underwent specific health examinations in Kanazawa, Japan between 2009 and 2018 to collect data on basic physical information, lifestyle habits, and laboratory parameters such as diabetes, lipid metabolism, renal function, and liver function. Four machine learning algorithms were used: Random Forest, Logistic regression, Light Gradient Boosting Machine, and eXtreme-Gradient-Boosting (XGBoost). The XGBoost model exhibited superior area under the curve (AUC), with mean values of 0.770 (± 0.003), 0.758 (± 0.003), and 0.845 (± 0.005) for stroke, IHD, and CCVD, respectively. The results of the five causal inference analyses were summarized, and lifestyle behavior changes were observed after the onset of CCVD. A causal relationship from ‘reduced mastication’ to ‘weight gain’ was found for all causal species theory methods. This prediction algorithm can screen for asymptomatic myocardial ischemia and stroke. By selecting high-risk patients suspected of having CCVD, resources can be used more efficiently for secondary testing.

10 February 2022 in Circulation Reports
Verified
Journal Article
Open access
PDF file
MKMasaki Kawakami
Masaki Kawakami
SKShigehiro Karashima
Shigehiro Karashima
KMKento Morita
Kento Morita
HTHayato Tada
Hayato Tada
HOHirofumi Okada
Hirofumi Okada
MKMasa-Aki Kawashiri
Masa-Aki Kawashiri
Background:Atrial fibrillation (AF) is the most common arrhythmia and is associated with increased thromboembolic stroke risk and heart failure. Although various prediction models for AF risk have been developed using machine learning, their output cannot be accurately explained to doctors and patients. Therefore, we developed an explainable model with high interpretability and accuracy accounting for the non-linear effects of clinical characteristics on AF incidence.Methods and Results:Of the 489,073 residents who underwent specific health checkups between 2009 and 2018 and were registered in the Kanazawa Medical Association database, data were used for 5,378 subjects with AF and 167,950 subjects with normal electrocardiogram readings. Forty-seven clinical parameters were combined using a generalized additive model algorithm. We validated the model and found that the area under the curve, sensitivity, and specificity were 0.964, 0.879, and 0.920, respectively. The 9 most important variables were the physical examination of arrhythmia, a medical history of coronary artery disease, age, hematocrit, γ-glutamyl transpeptidase, creatinine, hemoglobin, systolic blood pressure, and HbA1c. Further, non-linear relationships of clinical variables to the probability of AF diagnosis were visualized.Conclusions:We established a novel AF risk explanation model with high interpretability and accuracy accounting for non-linear information obtained at general health checkups. This model contributes not only to more accurate AF risk prediction, but also to a greater understanding of the effects of each characteristic.