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Advanced Neurology                                                Diffusion model for brain tumor classification



            domain of DL, CNNs have emerged as a prominent tool   In that regard, the vanilla GAN paradigm, which was
            for brain tumor classification using MRI. 13       initially proposed in 2014, has emerged as a promising
              Researchers have utilized brain datasets, such as the   solution  for  representation  learning  and  domain
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            Figshare dataset created by Cheng,  to develop efficient   transfer.  Vanilla GAN is capable of generating large
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            classification methods. Meanwhile, dual-tree complex   and heterogeneous datasets as part of a controllable
            wavelet transform and bag-of-words schemes have been   iterative refinement process, providing new samples
            actively  and  successfully  used  as  feature-extraction   that are statistically faithful to the original distribution
            mechanisms with, in some cases, 100% accuracy when   while excluding personal identifiers. Recent studies have
            combined with SVM.  More recently, CNN models,     shown the utility of GAN-based approaches, including
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            often enlarged through transfer learning, have achieved   deep convolutional GAN,  Pix2Pix,  CycleGAN,
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            significant performance gains. For example, the application   TumorGAN,   Adaptive  gradient  GAN  (AGGrGAN),
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            of transfer learning enabled GoogleNet to achieve 97%   and Wasserstein GAN,   for augmenting brain tumor
            accuracy on the Figshare dataset when combined with   imaging datasets. These models have consistently
            SVM. 26                                            reported notable gains in classification performance. By
                                                               approximating the underlying data distribution, GANs
              Subsequent studies on brain tumor detection have   enhance the likelihood of modeling target classes, thereby
            established the  use  of  deep  transfer  learning  to  help   facilitating the extraction of  discriminative features  and
            thousands of people across continents. In one such study,   improving visual performance. 35
            the diagnostic performance of nine pre-trained transfer-
                                                                 While GANs have been proven effective in generating
            learning  classifiers,  including  InceptionResNetV2,  synthetic data and enhancing model performance, they
            Xception, and ResNet50, was compared using a fine-  also present certain limitations, such as mode collapse
            grained classification approach applied to the Figshare   and training instability.  These challenges can hinder
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            dataset. 27  InceptionResNetV2  outperformed  its  the generation of diverse and high-quality synthetic data.
            counterparts, achieving an accuracy of 98.91%. Further   To address these issues, this study adopted the diffusion
            testing on hybrid architectures, in which CNNs perform   model, an advanced GAN architecture that offers a more
            feature extraction and SVMs serve as the classification   stable and robust framework for data generation. Diffusion
            mechanism, has provided additional evidence for the   model refines images through an iterative diffusion
            effectiveness of transfer-learning algorithms.
                                                               process, gradually removing noise and enhancing image
              The  use  of  various  DL  models  and  transfer-learning   quality. 50,51  This method allows for the generation of highly
            methods on brain tumor classification has now been   realistic and diverse synthetic datasets, which are crucial
            documented in many studies. Among these experiments,   for improving the accuracy and reliability of brain tumor
            architectures including InceptionV3, ResNet50, VGG16,   classification models while simultaneously safeguarding
            and VGG19 have demonstrated accuracies ranging from   patient privacy.  In light of this, a novel CDCNN model
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            91% to 99%. 28-32  Furthermore, augmentation strategies   for brain tumor classification was proposed in this study.
            employing advanced mechanisms, such as faster region-  In addition, the study evaluated the performance of five
            based CNNs, have contributed to further improvements in   state-of-the-art DL models, including ResNet50, VGG16,
            classification accuracy. 33                        VGG19, and InceptionV3, using publicly available
              Shorten and Khoshgoftaar  emphasized that to     benchmark datasets. Across a comprehensive parameter
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            improve classifier training and to reduce human    analysis, the effectiveness of these models in brain tumor
            dependence, image augmentation is inevitable. These   classification was compared.
            augmentation measures geometrically and chromatically   2. Methodology
            modify initial datasets. However, such transformation
            methods often have limiting constraints, making their   Figure 1 displays the flowchart of the experimental design
            resulting images provide limited content variation. 34,35    for classifying brain tumor images.
            Moreover, modern clinical neuroimaging research
            presents severe privacy and confidentiality risks due   2.1. Data collection
            to  the  inclusion  of  patient  information  into  analytic   The dataset used in this study was sourced from the Kaggle
            pipelines. Collections containing facial images, for   open-source brain tumor classification dataset. 53,54  It
            example, can enable re-identification through facial   consists of 3,264 MRI slices divided into four categories:
            recognition systems. 16,17,36,37  These risks are not mitigated   Glioma, meningioma, pituitary tumor, and normal
            by conventional augmentation methods that are useful in   tissue. The original repository did not provide explicit
            improving distributional features.                 information on MRI acquisition parameters or specific


            Volume 4 Issue 4 (2025)                         90                           doi: 10.36922/AN025130025
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