Beyond the Black Box: Smarter Medical Imaging with Expert Knowledge

Author: Denis Avetisyan


A new framework combines the power of artificial intelligence with established medical expertise to create more reliable and interpretable image analysis.

The MedXAI framework cultivates knowledge extraction not through construction, but through a Retrieval-Augmented and Self-Verifying process leveraging large language models, anticipating inevitable imperfections inherent in any system designed to interpret complex data.
The MedXAI framework cultivates knowledge extraction not through construction, but through a Retrieval-Augmented and Self-Verifying process leveraging large language models, anticipating inevitable imperfections inherent in any system designed to interpret complex data.

MedXAI integrates deep learning, large language models, and neuro-symbolic reasoning to address challenges in rare-class learning, domain generalization, and explainability in medical imaging.

Despite advances in medical image analysis, deep learning models often struggle with real-world distribution shifts and exhibit bias towards common pathologies, hindering reliable clinical translation. This work introduces MedXAI: A Retrieval-Augmented and Self-Verifying Framework for Knowledge-Guided Medical Image Analysis, a neuro-symbolic approach that integrates deep vision with clinician-derived expert knowledge and large language models to improve both accuracy and interpretability. Our results demonstrate consistent gains in cross-domain generalization and rare-class identification across multiple modalities, suggesting that explicitly incorporating medical expertise can address critical limitations of current AI systems. Could this framework pave the way for more robust and trustworthy medical AI solutions, particularly for underrepresented diseases?


The Illusion of Signal in the Noise

Deep learning algorithms, while demonstrating remarkable progress in many fields, frequently encounter difficulties when tasked with identifying infrequent medical conditions. This “rare-class learning” problem arises because these models are typically trained on vast datasets where common ailments significantly outnumber subtle, yet critical, anomalies. Consequently, the algorithms become adept at recognizing prevalent conditions, but struggle to detect the less frequent cases – such as atypical pneumonia or specific genetic disorders – that demand immediate attention. The inherent imbalance in training data biases the models towards prioritizing majority classes, leading to diminished sensitivity and potentially missed diagnoses when encountering these crucial, yet uncommon, presentations. This limitation underscores the need for specialized techniques capable of effectively learning from limited data and highlighting subtle indicators often overlooked by conventional approaches.

A significant challenge in medical artificial intelligence lies in the tendency of deep learning models to favor prevalent diagnoses, potentially obscuring life-threatening but infrequently occurring conditions. These algorithms, trained on vast datasets, learn to recognize patterns associated with common ailments with high accuracy, but often lack the sensitivity to detect the subtle indicators of rare diseases. For example, specific, atypical seizure manifestations or nuanced signs of rare retinal pathologies may be misinterpreted as noise or dismissed due to their low representation in the training data. This prioritization of commonality introduces a critical risk, as the very conditions demanding the most astute diagnosis – those presenting rarely but carrying significant morbidity – are precisely those most likely to be overlooked, highlighting the need for AI systems capable of balanced and equitable diagnostic performance across the entire spectrum of disease prevalence.

Current diagnostic approaches employing artificial intelligence often fall short because they struggle to synthesize the subtle, context-dependent insights of medical experts with the sheer volume of data present in complex medical imaging. While algorithms excel at pattern recognition, they frequently miss critical nuances – the barely perceptible indicators honed by years of clinical experience – leading to both inaccuracies and a lack of transparency in their conclusions. This limitation isn’t simply a matter of needing more data; it’s a fundamental challenge in translating qualitative, expert-driven reasoning into quantitative algorithms. Consequently, diagnoses can be unreliable, and clinicians are often hesitant to fully trust ‘black box’ AI systems, hindering their integration into practical healthcare settings and demanding methods that prioritize both performance and interpretability.

A significant impediment to deploying medical AI lies in its limited ability to generalize beyond the datasets on which it was initially trained – a challenge known as cross-domain generalization. Models demonstrating high accuracy within a single hospital or patient demographic often experience substantial performance drops when applied to data from different institutions or populations, due to variations in imaging protocols, patient characteristics, and disease prevalence. This lack of robustness stems from the models learning spurious correlations specific to the training environment, rather than the underlying biological indicators of disease. Consequently, a diagnostic tool refined on data from one center may fail to reliably detect anomalies in a new clinical setting, hindering widespread adoption and potentially leading to misdiagnosis or delayed treatment. Bridging this generalization gap requires innovative strategies, such as domain adaptation techniques and the development of models less susceptible to dataset-specific biases, to ensure equitable and effective healthcare solutions for all.

DeepXSOZ is a hybrid AI architecture that combines deep learning with expert knowledge to accurately localize seizure onset zones from resting-state fMRI data, providing both a diagnosis and an explanation of its reasoning.
DeepXSOZ is a hybrid AI architecture that combines deep learning with expert knowledge to accurately localize seizure onset zones from resting-state fMRI data, providing both a diagnosis and an explanation of its reasoning.

Bridging the Gap: Neuro-Symbolic Systems as Clinical Allies

MedXAI addresses the shortcomings of traditional, data-exclusive deep learning models in medical applications by implementing a neuro-symbolic architecture. This framework moves beyond purely statistical correlations by explicitly incorporating structured clinical knowledge – encompassing established medical rules, guidelines, and expert insights – with the learned representations of deep neural networks. The integration aims to improve model accuracy, robustness, and, crucially, interpretability, allowing clinicians to understand why a model arrived at a particular conclusion rather than simply receiving a prediction. By combining the pattern-recognition capabilities of deep learning with the explicit reasoning of knowledge-based systems, MedXAI seeks to create AI solutions that are both powerful and trustworthy in complex medical contexts.

MedXAI incorporates Expert Knowledge Systems (EKS) to represent and utilize pre-existing clinical rules and insights within the deep learning model. These EKS are formalized representations of medical knowledge, often derived from clinical guidelines, medical ontologies, and expert consensus. The Expert Knowledge Processor (EKP) functions as the interface between the EKS and the neural network, translating symbolic knowledge into a format compatible with the model’s numerical representations. This allows domain-specific constraints, diagnostic criteria, or treatment protocols to be directly embedded into the AI’s reasoning process, augmenting data-driven learning and enabling more informed and reliable predictions.

The EKSAII Algorithm functions as the core integration mechanism within MedXAI, addressing the limitations of standalone deep learning and knowledge-based systems. It operates by leveraging the pattern recognition capabilities of neural networks to process complex, high-dimensional clinical data, while simultaneously utilizing symbolic reasoning – encoded expert knowledge – to provide contextual understanding and constraint satisfaction. This combination is achieved through a modular architecture where neural network outputs are translated into symbolic representations, which are then subjected to logical inference using the expert knowledge base. The resulting inferences are subsequently used to refine the neural network’s predictions, creating a feedback loop that enhances both accuracy and interpretability. Specifically, the algorithm uses weighted logical operations to combine neural confidence scores with the truth values derived from expert rules, allowing for nuanced decision-making that reflects both data-driven insights and established clinical principles.

The MedXAI framework utilizes a decision tree structure, constructed via Hunt’s Algorithm, to explicitly represent and apply expert clinical knowledge. Hunt’s Algorithm is employed to generate a tree that systematically categorizes patient data based on defined medical rules and criteria. This tree serves as an interpretable layer within the deep learning model, allowing for transparent reasoning by mapping inputs to outputs through a series of logical conditions. The resulting decision tree facilitates the incorporation of established medical guidelines and physician expertise, enhancing the model’s ability to provide explainable and clinically relevant predictions.

An integrated deep learning and expert knowledge system utilizing an iterative binary classification approach achieves 84% accuracy across five diabetic retinopathy classes by sequentially applying clinically informed decision-making.
An integrated deep learning and expert knowledge system utilizing an iterative binary classification approach achieves 84% accuracy across five diabetic retinopathy classes by sequentially applying clinically informed decision-making.

Quantifying the Value: Separating Signal from Noise

The EKSAII algorithm quantifies the effect of incorporating expert knowledge on the separability of rare classes through the calculation of the Gini Index and Entropy Imbalance Gain. The Gini Index, a measure of inequality ranging from 0 to 1, assesses the distribution of expert-informed probabilities across classes, with lower values indicating better separation. Entropy Imbalance Gain evaluates the reduction in entropy achieved by weighting features according to expert input; it is calculated as the difference between the entropy of the original feature distribution and the weighted distribution. These metrics provide a numerical assessment of how effectively expert knowledge improves the model’s discrimination between infrequent and common conditions, allowing for iterative refinement of the knowledge integration process.

MedXAI’s optimization of metrics such as the Gini Index and Entropy Imbalance Gain directly correlates with a measurable improvement in the identification of rare disease classes. Quantitative evaluation demonstrates a 10% increase in F1 scores for these classes, indicating enhanced precision and recall in diagnosing infrequent conditions. This performance gain signifies a substantial reduction in both false positive and false negative diagnoses within the rare disease cohort, validating the efficacy of incorporating expert knowledge to address challenges posed by imbalanced datasets common in medical applications.

Synthetic Minority Oversampling Technique (SMOTE) is incorporated into the MedXAI framework to mitigate the effects of class imbalance, a common issue in medical datasets where instances of rare diseases are significantly fewer than those of common conditions. SMOTE operates by creating synthetic examples of the minority class, effectively increasing its representation in the training data without duplicating existing samples. This is achieved by interpolating between existing minority class instances, generating new, plausible data points. By balancing the class distribution, SMOTE reduces the bias towards the majority class during model training, leading to improved recall and precision for the minority, or rare, disease classes and contributing to overall performance gains.

MedXAI leverages deep learning architectures for automated feature extraction from medical images, specifically employing both Convolutional Neural Networks (CNNs) and Vision Transformers (ViTs). CNNs utilize convolutional layers to identify spatial hierarchies and patterns within images, proving effective for identifying localized features indicative of disease. Vision Transformers, conversely, apply self-attention mechanisms to capture long-range dependencies and global context within the images, enabling the identification of subtle indicators potentially missed by CNNs. The combination of these architectures allows MedXAI to generate robust feature representations suitable for downstream classification tasks, improving diagnostic accuracy and reducing reliance on manual feature engineering.

The Illusion of Understanding: Making the Machine Explain Itself

MedXAI distinguishes itself through a neuro-symbolic design that prioritizes transparency by generating human-understandable explanations for its diagnostic predictions. Rather than operating as a ‘black box’, the system leverages the power of Large Language Models, and specifically GPT-4, to translate complex algorithmic reasoning into natural language. This allows clinicians to not only see what a diagnosis is, but also why the system arrived at that conclusion, detailing the key features and logical steps involved. This capability is crucial for building trust and facilitating informed decision-making, moving beyond simple prediction to genuine clinical insight.

The capacity for transparent reasoning fundamentally alters the interaction between artificial intelligence and medical professionals. MedXAI’s design not only delivers predictions but also articulates the logic behind them, fostering a crucial level of clinical confidence in its assessments. This explainability directly supports more informed decision-making, allowing physicians to readily evaluate the AI’s rationale alongside patient data. Crucially, this system dramatically reduces the burden on specialists; studies demonstrate a reduction of over 84.2% in manual review effort for critical tasks like pinpointing seizure origins and grading the severity of diabetic retinopathy. By automating much of the initial analysis and clearly presenting supporting evidence, MedXAI allows experts to focus their valuable time on complex cases and patient care, rather than tedious data scrutiny.

MedXAI demonstrates a significant advancement in the generalization capabilities of artificial intelligence within medical image analysis. By incorporating explicitly defined expert knowledge into its framework, the system achieves improved performance across diverse datasets-reaching an accuracy of 67.95% on the MDG task and 65.5% on SDG (MESSIDOR2). These results surpass those obtained by standalone Vision Transformer (ViT) models, which achieved 61.2% and baseline performance respectively. This capacity for ‘cross-domain generalization’ suggests that MedXAI is less reliant on dataset-specific nuances, offering a more robust and adaptable solution for clinical applications where data distribution can vary considerably between institutions and patient populations.

A key strength of the MedXAI system lies in its ability to incorporate structured, pre-existing medical knowledge, which significantly bolsters model robustness and mitigates the potential for spurious correlations. By explicitly representing established clinical understanding, the system moves beyond simply identifying patterns in data; it grounds its predictions in known medical principles. This approach not only enhances the reliability of diagnoses – particularly when faced with incomplete or noisy data – but also reduces the likelihood of the model making decisions based on accidental correlations that lack genuine clinical significance. The result is a more dependable and trustworthy AI, capable of consistently accurate performance and less susceptible to the pitfalls of data-driven bias.

The pursuit of robust medical image analysis, as demonstrated by MedXAI, isn’t about imposing order, but acknowledging inherent complexity. The framework’s integration of expert knowledge and large language models doesn’t eliminate ambiguity-it navigates it. As John von Neumann observed, “There is no possibility of absolute certainty.” This resonates deeply; MedXAI doesn’t promise infallible diagnoses, but a system capable of self-verification and adaptation, mitigating rare-class bias through a neuro-symbolic approach. Stability, in this context, isn’t a fixed state, but an illusion meticulously cached within the framework’s ability to retrieve and reason from existing medical knowledge. Chaos isn’t failure-it’s nature’s syntax, and MedXAI, through its architecture, attempts to parse it.

What Lies Ahead?

The architecture, as presented, feels less like a solution and more like a carefully constructed containment field. MedXAI proposes grafting expert knowledge onto deep learning, a gesture that implicitly acknowledges the inherent brittleness of purely data-driven systems. The question isn’t whether the retrieval-augmentation improves performance – it inevitably will, for a time – but rather what form the failure will take when the retrieved knowledge proves insufficient, or worse, actively misleading. Every deployment is a small apocalypse, after all.

The pursuit of domain generalization, especially with rare-class learning, highlights a deeper truth: medical imaging isn’t a problem of pattern recognition; it’s a problem of incomplete information. The LLM component, while promising, simply shifts the burden of uncertainty. It’s a sophisticated interpolation engine, not a source of truth. The real challenge isn’t building models that appear to generalize, but accepting that all models are, fundamentally, local.

One suspects the documentation for such a system will be…sparse. No one writes prophecies after they come true. The field will likely drift toward more robust methods of uncertainty quantification, and perhaps a reluctant embrace of Bayesian approaches. Or, more likely, it will simply move on to the next framework, leaving the ghosts of prior failures to haunt the datasets.


Original article: https://arxiv.org/pdf/2512.10098.pdf

Contact the author: https://www.linkedin.com/in/avetisyan/

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2025-12-13 13:46