Abstract
Introduction: Diagnosis of occult atrial fibrillation (AF) is difficult as it is often asymptomatic, leading to under-detection. Current diagnostic tests have variable limitations in feasibility and accuracy. Machine learning is gaining greater traction for clinical decision-making and may help facilitate the detection of undiagnosed AF when applied to magnetic resonance imaging (MRI). We hypothesize that a machine learning algorithm increases the accurate classification of MRIs of stroke patients into those due to AF versus large artery atherosclerosis. Methods: Stroke aetiology for each patient was determined by a review of medical records and investigations. Patients with either AF or large artery atherosclerosis were included. Patients were randomly divided into the training and validation groups (4:1). A 3D convolutional neural network (ConvNeXt) was developed to train and validate the algorithm. After training, the models were evaluated using common metrics for binary classification. Results: A total of 235 patients were analysed (97 with AF, 138 without AF). The mean age of the sample was 71.1 (SD 14.2), and 35% were female. The best discriminative performance was obtained in the 5th fold of cross-validation (AUC-ROC 0.88), and the overall model performance was 0.81 ± 0.05. The best performing metrics were precision (0.84 ± 0.08) and the F1-score (0.77 ± 0.06). Conclusion: Our machine learning algorithm has reasonable classification power in categorizing stroke patients into those with and without underlying AF. Testing in external validation datasets is critical to confirm these results.
Plain Language Summary
Atrial fibrillation (AF) is an abnormal heart rhythm which is a common cause of stroke. AF is associated with certain findings on brain imaging which can provide clues to the diagnosis. This paper showed the use of artificial intelligence, when applied to MRI brain imaging, can assist in the differentiating AF from another common cause of stroke, large artery atherosclerosis.