Semi-Supervised Deep Subspace Embedding for Binary Classification of Sella Turcica

In orthodontics, the manual tracing of cephalometric radiographs is a common practice, where the Sella Turcica (ST) serves as a reference point. The radiologist often manually traces the outline of the sella using manual tools (e.g., calipers on radiographs). Perhaps the inherent complexity and vari...

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Main Authors: Kaushlesh Singh Shakya, Azadeh Alavi, Julie Porteous, Priti Khatri, Amit Laddi, Manojkumar Jaiswal, Vinay Kumar
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/14/23/11154
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author Kaushlesh Singh Shakya
Azadeh Alavi
Julie Porteous
Priti Khatri
Amit Laddi
Manojkumar Jaiswal
Vinay Kumar
author_facet Kaushlesh Singh Shakya
Azadeh Alavi
Julie Porteous
Priti Khatri
Amit Laddi
Manojkumar Jaiswal
Vinay Kumar
author_sort Kaushlesh Singh Shakya
collection DOAJ
description In orthodontics, the manual tracing of cephalometric radiographs is a common practice, where the Sella Turcica (ST) serves as a reference point. The radiologist often manually traces the outline of the sella using manual tools (e.g., calipers on radiographs). Perhaps the inherent complexity and variability in the shapes of sella and the lack of advanced assessment tools make the classification of sella challenging, as it requires extensive training, skills, time, and manpower to detect subtle changes that often may not be apparent. Moreover, existing semi-supervised learning (SSL) methods face key limitations such as shift invariance, inadequate feature representation, overfitting on small datasets, and a lack of generalization to unseen variations in ST morphology. Medical imaging data are often unlabeled, limiting the training of automated classification systems for ST morphology. To address these limitations, a novel semi-supervised deep subspace embedding (SSLDSE) framework is proposed. This approach integrates real-time stochastic augmentation to significantly expand the training dataset and introduce natural variability in the ST morphology, overcoming the constraints of small and non-representative datasets. Non-linear features are extracted and mapped to a non-linear subspace using Kullback–Leibler divergence, which ensures that the model remains consistent despite image transformations, thus resolving issues related to shift invariance. Additionally, fine-tuning the Inception-ResNet-v2 network on these enriched features reduces retraining costs when new unlabeled data becomes available. t-distributed stochastic neighbor embedding (t-SNE) is employed for effective feature representation through manifold learning, capturing complex patterns that previous methods might miss. Finally, a zero-shot classifier is utilized to accurately categorize the ST, addressing the challenge of classifying new or unseen variations. Further, the proposed SSLDSE framework is evaluated through comparative analysis with the existing methods (Active SSL, GAN SSL, Contrastive SSL, Modified Inception-ResNet-v2) for ST classification using various evaluation metrics. The SSLDSE and the existing methods are trained on our dataset (sourced from PGI Chandigarh, India), and a blind test is conducted on the benchmark dataset (IEEE ISBI 2015). The proposed method improves classification accuracy by 15% compared to state-of-the-art models and reduces retraining costs.
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spelling doaj-art-43e00d94dff146038123eadb3a1c7b082024-12-13T16:22:59ZengMDPI AGApplied Sciences2076-34172024-11-0114231115410.3390/app142311154Semi-Supervised Deep Subspace Embedding for Binary Classification of Sella TurcicaKaushlesh Singh Shakya0Azadeh Alavi1Julie Porteous2Priti Khatri3Amit Laddi4Manojkumar Jaiswal5Vinay Kumar6School of Computing Technologies, RMIT University, Melbourne, VIC 3000, AustraliaSchool of Computing Technologies, RMIT University, Melbourne, VIC 3000, AustraliaSchool of Computing Technologies, RMIT University, Melbourne, VIC 3000, AustraliaAcademy of Scientific & Innovative Research (AcSIR), Ghaziabad 201002, IndiaAcademy of Scientific & Innovative Research (AcSIR), Ghaziabad 201002, IndiaOral Health Sciences Centre, Post Graduate Institute of Medical Education & Research (PGIMER), Chandigarh 160012, IndiaOral Health Sciences Centre, Post Graduate Institute of Medical Education & Research (PGIMER), Chandigarh 160012, IndiaIn orthodontics, the manual tracing of cephalometric radiographs is a common practice, where the Sella Turcica (ST) serves as a reference point. The radiologist often manually traces the outline of the sella using manual tools (e.g., calipers on radiographs). Perhaps the inherent complexity and variability in the shapes of sella and the lack of advanced assessment tools make the classification of sella challenging, as it requires extensive training, skills, time, and manpower to detect subtle changes that often may not be apparent. Moreover, existing semi-supervised learning (SSL) methods face key limitations such as shift invariance, inadequate feature representation, overfitting on small datasets, and a lack of generalization to unseen variations in ST morphology. Medical imaging data are often unlabeled, limiting the training of automated classification systems for ST morphology. To address these limitations, a novel semi-supervised deep subspace embedding (SSLDSE) framework is proposed. This approach integrates real-time stochastic augmentation to significantly expand the training dataset and introduce natural variability in the ST morphology, overcoming the constraints of small and non-representative datasets. Non-linear features are extracted and mapped to a non-linear subspace using Kullback–Leibler divergence, which ensures that the model remains consistent despite image transformations, thus resolving issues related to shift invariance. Additionally, fine-tuning the Inception-ResNet-v2 network on these enriched features reduces retraining costs when new unlabeled data becomes available. t-distributed stochastic neighbor embedding (t-SNE) is employed for effective feature representation through manifold learning, capturing complex patterns that previous methods might miss. Finally, a zero-shot classifier is utilized to accurately categorize the ST, addressing the challenge of classifying new or unseen variations. Further, the proposed SSLDSE framework is evaluated through comparative analysis with the existing methods (Active SSL, GAN SSL, Contrastive SSL, Modified Inception-ResNet-v2) for ST classification using various evaluation metrics. The SSLDSE and the existing methods are trained on our dataset (sourced from PGI Chandigarh, India), and a blind test is conducted on the benchmark dataset (IEEE ISBI 2015). The proposed method improves classification accuracy by 15% compared to state-of-the-art models and reduces retraining costs.https://www.mdpi.com/2076-3417/14/23/11154sella turcicadeep learningsemi supervised learningmanifold learningmedical imagesclassification
spellingShingle Kaushlesh Singh Shakya
Azadeh Alavi
Julie Porteous
Priti Khatri
Amit Laddi
Manojkumar Jaiswal
Vinay Kumar
Semi-Supervised Deep Subspace Embedding for Binary Classification of Sella Turcica
Applied Sciences
sella turcica
deep learning
semi supervised learning
manifold learning
medical images
classification
title Semi-Supervised Deep Subspace Embedding for Binary Classification of Sella Turcica
title_full Semi-Supervised Deep Subspace Embedding for Binary Classification of Sella Turcica
title_fullStr Semi-Supervised Deep Subspace Embedding for Binary Classification of Sella Turcica
title_full_unstemmed Semi-Supervised Deep Subspace Embedding for Binary Classification of Sella Turcica
title_short Semi-Supervised Deep Subspace Embedding for Binary Classification of Sella Turcica
title_sort semi supervised deep subspace embedding for binary classification of sella turcica
topic sella turcica
deep learning
semi supervised learning
manifold learning
medical images
classification
url https://www.mdpi.com/2076-3417/14/23/11154
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