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Publicações

Publicações por Mohammad Hossein Zolfagharnasab

2025

Predicting Aesthetic Outcomes of Breast Cancer Surgery: A Robust and Explainable Image Retrieval Approach

Autores
Ferreira, P; Zolfagharnasab, MH; Gonçalves, T; Bonci, E; Mavioso, C; Cardoso, MJ; Cardoso, JS;

Publicação
Deep-Breath@MICCAI

Abstract
Accurate retrieval of post-surgical images plays a critical role in surgical planning for breast cancer patients. However, current content-based image retrieval methods face challenges related to limited interpretability, poor robustness to image noise, and reduced generalization across clinical settings. To address these limitations, we propose a multistage retrieval pipeline integrating saliency-based explainability, noise-reducing image pre-processing, and ensemble learning. Evaluated on a dataset of post-operative breast cancer patient images, our approach achieves contrastive accuracy of 77.67% for Excellent/Good and 84.98% for Fair/Poor outcomes, surpassing prior studies by 8.37% and 11.80%, respectively. Explainability analysis provided essential insight by showing that feature extractors often attend to irrelevant regions, thereby motivating targeted input refinement. Ablations show that expanded bounding box inputs improve performance over original images, with gains of 0.78% and 0.65% contrastive accuracy for Excellent/Good and Fair/Poor, respectively. In contrast, the use of segmented images leads to a performance drop (1.33% and 1.65%) due to the loss of contextual cues. Furthermore, ensemble learning yielded additional gains of 0.89% and 3.60% over the best-performing single-model baselines. These findings underscore the importance of targeted input refinement and ensemble integration for robust and generalizable image retrieval systems.

2025

Towards Robust Breast Segmentation: Leveraging Depth Awareness and Convexity Optimization For Tackling Data Scarcity

Autores
Zolfagharnasab, MH; Gonçalves, T; Ferreira, P; Cardoso, MJ; Cardoso, JS;

Publicação
Deep-Breath@MICCAI

Abstract
Breast segmentation has a critical role for objective pre and postoperative aesthetic evaluation but challenged by limited data (privacy concerns), class imbalance, and anatomical variability. As a response to the noted obstacles, we introduce an encoder–decoder framework with a Segment Anything Model (SAM) backbone, enhanced with synthetic depth maps and a multiterm loss combining weighted crossentropy, convexity, and depth alignment constraints. Evaluated on a 120patient dataset split into 70% training, 10% validation, and 20% testing, our approach achieves a balanced test dice score of 98.75%—a 4.5% improvement over prior methods—with dice of 95.5% (breast) and 89.2% (nipple). Ablations show depth injection reduces noise and focuses on anatomical regions, yielding dice gains of 0.47% (body) and 1.04% (breast). Geometric alignment increases convexity by almost 3% up to 99.86%, enhancing geometric plausibility of the nipple masks. Lastly, crossdataset evaluation on CINDERELLA samples demonstrates robust generalization, with small performance gain primarily attributable to differences in annotation styles.

2025

Towards Utilizing Robust Radiance Fields for 3D Reconstruction of Breast Aesthetics

Autores
Pinto, G; Zolfagharnasab, MH; Teixeira, LF; Cruz, H; Cardoso, MJ; Cardoso, JS;

Publicação
Deep-Breath@MICCAI

Abstract
3D models are crucial in predicting aesthetic outcomes in breast reconstruction, supporting personalized surgical planning, and improving patient communication. In response to this necessity, this is the first application of Radiance Fields to 3D breast reconstruction. Building on this, the work compares six SoTA 3D reconstruction models. It introduces a novel variant tailored to medical contexts: Depth-Splatfacto, designed to improve denoising and geometric consistency through pseudo-depth supervision. Additionally, we extended model training to grayscale, which enhances robustness under grayscale-only input constraints. Experiments on a breast cancer patient dataset demonstrate that Splatfacto consistently outperforms others, delivering the highest reconstruction quality (PSNR 27.11, SSIM 0.942) and the fastest training times (×1.3 faster at 200k iterations). At the same time, the depth-enhanced variant offers an efficient and stable alternative with minimal fidelity loss. The grayscale train improves speed by ×1.6 with a PSNR drop of 0.70. Depth-Splatfacto further improves robustness, reducing PSNR variance by 10% and making images less blurry across test cases. These results establish a foundation for future clinical applications, supporting personalized surgical planning and improved patient-doctor communication.

2025

Predicting Aesthetic Outcomes in Breast Cancer Surgery: A Multimodal Retrieval Approach

Autores
Zolfagharnasab, MH; Freitas, N; Gonçalves, T; Bonci, E; Mavioso, C; Cardoso, MJ; Oliveira, HP; Cardoso, JS;

Publicação
ARTIFICIAL INTELLIGENCE AND IMAGING FOR DIAGNOSTIC AND TREATMENT CHALLENGES IN BREAST CARE, DEEP-BREATH 2024

Abstract
Breast cancer treatments often affect patients' body image, making aesthetic outcome predictions vital. This study introduces a Deep Learning (DL) multimodal retrieval pipeline using a dataset of 2,193 instances combining clinical attributes and RGB images of patients' upper torsos. We evaluate four retrieval techniques: Weighted Euclidean Distance (WED) with various configurations and shallow Artificial Neural Network (ANN) for tabular data, pre-trained and fine-tuned Convolutional Neural Networks (CNNs) and Vision Transformers (ViTs), and a multimodal approach combining both data types. The dataset, categorised into Excellent/Good and Fair/Poor outcomes, is organised into over 20K triplets for training and testing. Results show fine-tuned multimodal ViTs notably enhance performance, achieving up to 73.85% accuracy and 80.62% Adjusted Discounted Cumulative Gain (ADCG). This framework not only aids in managing patient expectations by retrieving the most relevant post-surgical images but also promises broad applications in medical image analysis and retrieval. The main contributions of this paper are the development of a multimodal retrieval system for breast cancer patients based on post-surgery aesthetic outcome and the evaluation of different models on a new dataset annotated by clinicians for image retrieval.

2024

A Comparative Analysis of Resource-Efficient Machine Learning Models in News Categorization

Autores
Zolfagharnasb, MH; Damari, S;

Publicação
U.Porto Journal of Engineering

Abstract
The constant stream of news nowadays highlights the necessity for meticulous assessment to ensure that the information accurately reaches its intended audience with the least amount of delay least delay. Despite the flexibility and efficiency of Deep Learning (DL) models, their intricate training and substantial resource demands pose significant challenges for their deployment in real-time applications. In this regard, this study evaluates the performance of resource-efficient Machine Learning (ML) techniques – Multinomial Naive Bayes (MNB), Random Forest (RF), Support Vector Machine (SVM), and Logistic Regression (LR) – in categorizing news. Based on the results, all the evaluated models attain a commendable level of accuracy in news categorization. Notably, the SVM excels, achieving an accuracy rate of 98% and a mean squared error of 0.28. This performance exemplifies the robust effectiveness of classical ML models in the categorization of news, particularly when enhanced by a suitably tailored preprocessing pipeline. © 2024, Universidade do Porto - Faculdade de Engenharia. All rights reserved.

2020

Novel analysis of second law and irreversibility for a solar power plant using heliostat field and molten salt

Autores
Zolfagharnasab, MH; Aghanajafi, C; Kavian, S; Heydarian, N; Ahmadi, MH;

Publicação
Energy Science & Engineering

Abstract
AbstractNowadays, the low efficiency of solar energy power plant systems brings about uneconomical performance and high-cost uncompetitive industries compared with the traditional fossil fuel ones. In order to overcome these kinds of issues, in this study, the performance of a solar tower coupled with a Rankine cycle is scrutinized using the first and second laws of thermodynamic. Moreover, a numerical code has been developed in the GNU Octave software environment to calculate the precise value for both energy and exergy losses of each component. Furthermore, the sensitivity analysis approach corresponds to the variation of several inner parameters such as direct normal irradiation (DNI), molten salt outlet temperature (MSOT), and the molten salt velocity (MSV), environmental parameters such as wind speed and ambient temperature have been performed. In addition, the overall losses are calculated by considering all possible forms of losses such as convection, conduction, reflection, and emission, and also, the portion of each source of these losses are determined. The obtained results indicate that the maximum exergy loss occurs in the central receiver system (CRS), while the major energy loss occurs in the turbine located in the power block. The sensitivity analysis shows that the rise of DNI significantly increases the exergy%energy efficiency of the cycle and also, the portion of loss related to emission heat transfer would be enhanced. Moreover, the variation of the MSV and MSOT illustrate influencing the performance of the cycle; consequently, the MSOT changes demonstrate a reverse relation with energy and direct relation with exergy efficiency. Accordingly, an optimum value of 650K is calculated for the MSOT as well as an optimum value of 2 m%s for the MSV. The environmental sensitivity analysis indicates that the enhancement of wind speed and ambient temperature has a negative impact on the net output of the cycle, which is not desirable.

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