Canine Cardiomegaly Detection: A Breakthrough in Deep Learning Diagnostics

By Dr Silpaja Chandrasekar, PhDReviewed by Susha Cheriyedath, M.Sc.Jan 24 2024

In a paper published in the journal Scientific Reports, researchers addressed the leading cause of death in dogs—cardiac disease—by exploring the potential of automatic cardiomegaly detection through deep learning methods. Despite their promising outcomes, challenges in aligning predicted results with input radiographs hindered the broader application of deep learning methods in clinical trials.

The researchers overcame this by amassing a substantial dataset of dog heart X-radiation (X-ray) images, developing a specialized dog heart labeling tool, and crafting a regressive vision transformer (RVT) model with an orthogonal layer. Experimental results demonstrated the model's state-of-the-art performance, offering a promising avenue for improving diagnostic accuracy in veterinary medicine.

Pet Health Revolution

The surge in awareness of pet health has prompted a focus on leveraging deep learning techniques for enhanced animal medical services, particularly in canine heart disease detection. While convolutional neural networks (CNN) show promise, the challenge lies in bridging deep learning methods with clinical trials.

Clinicians, lacking familiarity with deep learning, hesitate to trust results despite their high performance. Integrating widely accepted metrics like the vertebral heart scale (VHS) for heart enlargement diagnosis is essential, addressing the inefficiencies of manual determination. Overcoming challenges in interpreting deep learning outputs and establishing trust is crucial for accelerating canine cardiomegaly diagnosis, benefiting clinicians and institutions seeking advanced diagnostic tools.

Canine Cardiomegaly: RVT Model

Pet health has gained increasing attention in recent years, focusing on leveraging deep learning techniques for enhanced animal medical services, particularly in canine heart disease detection. VHS21 has been a standard method for assessing animal cardiac silhouette size. However, challenges arise in its calculation, primarily related to the error-prone estimation of long and short axes positions and the limited precision of the VHS score. Existing deep learning methods, treating cardiomegaly detection as an image classification problem, often need more clinical application due to the trust issues clinicians face with the interpretability of deep learning results.

The researchers propose a novel RVT model to address these challenges. The architecture comprises a pyramid vision transformer as an encoder, a feature fusion module (FFM) to predict six critical points of the VHS score, and an orthogonal layer ensuring the perpendicularity between specific line segments. The goal is to combine traditional and deep learning models to enhance accuracy and facilitate interpretation by clinicians with limited deep learning backgrounds.

The model incorporates a progressive vision transformer (PVT) block to overcome the limitations of single-scale low-resolution representations. This design features a progressive shrinking pyramid and spatial-reduction attention (SRA) to improve dense prediction tasks. Introducing the FFM extracts robust features by combining low-level details and high-level object information from the PVT encoder. Researchers employed convolutional layers for this purpose. Developing an orthogonal layer ensures the perpendicularity required for calculating the VHS score.

It checks the first four points' perpendicularity, contributing to a more accurate estimation. The objective function aims to accurately estimate the six key points and provide correct diagnosis results. The model minimizes cross-entropy loss to enhance diagnostic accuracy and mean square error to improve the closeness between predicted and ground truth key points. Researchers provide a clear outline of the overall training algorithm.

The proposed RVT model seeks to bridge the gap between traditional diagnostic methods and advanced deep learning models, addressing the interpretability concerns of clinicians. The training algorithm minimizes cross-entropy loss and mean square error, ensuring a comprehensive approach to accurate canine cardiomegaly assessment. The model's potential impact lies in its ability to provide trustworthy results while incorporating the benefits of deep learning advancements.

Efficiency and Superiority: RVT Analysis

In evaluating the RVT model on the DogHeart dataset, researchers compare it with 12 state-of-the-art classification models, detailing training parameters and experimental setups. It includes renowned models like Google's inception network (GoogleNet), visual geometry group 16 (VGG16), residual network 50 (ResNet50), densely connected convolutional networks 201 (DenseNet201), Inceptionv3, extreme inception (Xception), InceptionResnetV2, neural architecture search network large (NasnetLarge), vision transformer, CNN with transpose convolution (CONVT), and beit_large.

The assessment, conducted on a real-time extreme A6000 graphics processing unit (RTX A6000 GPU) with an Adam optimizer, highlights the RVT model's efficiency in convergence alongside Xception. The model demonstrates competitive performance with reasonable computational requirements, positioning it as a practical choice for applications in dog cardiomegaly classification.

The proposed RVT model outperforms other models, achieving the highest accuracy in standard cross-entropy training (c_accuracy) and the proposed loss function-based training (r_accuracy). Predicted results using the RVT model demonstrate close alignment with ground truth values. Further comparisons with baseline methods, NasnetLarge and CONVT, emphasize the superiority of the RVT model in predicting VHS scores and critical points.

In-depth category-wise analysis reveals that the RVT model predicts small heart categories, showcasing better accuracy and performance metrics than expected and large categories. Ablation studies explore the effectiveness of different model components, including feature layers, loss functions, and orthogonal layers. These studies demonstrate the importance of FFM, the superiority of mean squared error (MSE) loss over cross-entropy loss, and the significant impact of the proposed orthogonal layer on model performance. The ablation study results underscore the effectiveness and necessity of the proposed RVT model for accurate dog cardiomegaly assessment.

Conclusion

To sum up, this paper presents the RVT model, designed for dog cardiomegaly classification, using the DogHeart dataset. An incorporated orthogonal layer achieves superior performance compared to state-of-the-art methods. The model's adaptability extends to diverse medical image types beyond X-rays, and its potential for human cardiomegaly detection underscores its broader applicability. The user-friendly software facilitates clinical diagnosis, showcasing its impact across various medical domains.