Anatomically Faithful, Temporally Blind: LV EF Audit

Deep video models for ejection fraction accurately locate the left ventricle but ignore end-systolic and end-diastolic frames, revealing a critical gap in XAI

lunes, 27 de julio de 2026 • 3 min read • Q2BSTUDIO Team

Modelos de IA que ignoran los fotogramas clave

Artificial intelligence has shown astonishing ability to analyze medical images, especially in cardiology. Current deep video models estimate left ventricular ejection fraction (LVEF) from echocardiograms with near-expert accuracy. However, a recent audit reveals a troubling paradox: these models are anatomically faithful but temporally blind. They correctly locate the left ventricle in space but ignore the key frames (end-systole and end-diastole) that clinically define LVEF. This finding challenges the validity of post-hoc explanations — such as Grad-CAM for CNNs or Chefer relevance for transformers — used to certify that the model 'looks at the right place.'

The research, based on the EchoNet-Dynamic dataset, fine-tuned two distinct architectures: a self-supervised VideoMAE transformer and a Kinetics-pretrained R(2+1)D CNN. Both were audited with metrics like intersection-over-relevance (IoR) against LV masks, deletion AUC, and a temporal localization index on ES/ED frames. Results were clear: both models significantly exceeded chance in spatial accuracy (IoR 2.91x for VideoMAE and 1.98x for R(2+1)D), but temporal localization was indistinguishable from chance (0.97–1.00). Even with tubelet occlusion to separate attribution failure from actual model behavior, it confirmed that models do not preferentially rely on ES/ED frames (0.90x chance).

This implies that spatial faithfulness does not guarantee temporal faithfulness. Explainable AI (XAI) techniques can certify that a model attends to the left ventricle but mask that it ignores the decisive moments of the cardiac cycle. For clinical applications, this temporal blindness could lead to misdiagnosis, especially in patients with arrhythmias or irregular contractions where the systolic or diastolic peak deviates from the expected pattern.

In this context, Q2BSTUDIO emerges as a strategic partner for companies seeking to develop robust and auditable AI solutions. Our experience in developing custom software applications allows us to design models that explicitly incorporate temporal constraints, whether through frame-weighted losses, explicit temporal attention mechanisms, or full time-series validation. Additionally, we integrate cybersecurity and cloud computing (AWS/Azure) capabilities to ensure sensitive medical data is processed securely and scalably.

The LVEF model audit is just one example of a broader problem: many AI systems in medical imaging are evaluated only by overall accuracy, without decomposing temporal contribution. At Q2BSTUDIO we propose a multidimensional audit approach combining spatial, temporal and stability metrics, similar to how we would audit a BI/Power BI system to detect biases in historical data. Our AI agents can run automated test pipelines that generate spatiotemporal relevance maps and compare them against expert annotations, thus detecting patterns of temporal blindness before deploying the model into production.

The healthcare industry needs models that look not only at the right place but also at the right time. Ignoring the temporal dimension is like a cardiologist examining only a single static image of the heart, missing essential dynamics. With Q2BSTUDIO, organizations can build AI systems that integrate the full frame sequence, leveraging temporal transformer architectures and data augmentation techniques that preserve chronology. Furthermore, our cloud infrastructure on AWS/Azure allows processing large volumes of echocardiograms with low latency, while cybersecurity layers ensure compliance with regulations such as HIPAA or GDPR.

The combination of computer vision, intelligent agents and data analytics (BI / Power BI) enables companies not only to predict LVEF but also to explain why a certain value was reached, identifying whether the model used the correct frames or merely relied on spurious correlations. At Q2BSTUDIO we have developed proprietary methodologies to train models with losses that penalize lack of temporal attention, enabling networks to learn to distinguish between systole and diastole without explicit frame supervision, thus reducing manual annotation costs.

The original study emphasizes that spatial faithfulness does not imply temporal faithfulness, and that model explanations must be audited on both dimensions. For technology companies working on AI-assisted diagnostics, this is a call to action: it is not enough that the model has good overall performance; its reasoning must be verified to match the actual clinical process. At Q2BSTUDIO we offer consulting, development and auditing services for AI models, adapting to sectors such as healthcare, finance or manufacturing where the temporal dimension is critical. Contact us to discover how we can help you build models that are not only accurate but also explainable and reliable over time.

A BREAK?

Play for a moment before you go

OUR SERVICES

How we can help you

Do you have a project in mind?

Tell us your vision and we'll turn it into a software solution. Whatever the scope, we make your idea real.