Correlation between myocardial radiomics features at the left atrium-left atrial appendage junction and stroke risk in atrial fibrillation patients: a retrospective case-control study.

OBJECTIVE

This study aimed to systematically evaluate the microstructure changes of the myocardium at the left atrium-left atrial appendage (LA-LAA) junction in patients with atrial fibrillation (AF)-related cardioembolic stroke, and to explore its potential role as an imaging marker associated with stroke.

METHODS

This retrospective study included four groups: AF-related cardioembolic stroke group (n = 60), AF-non-stroke group (n = 29), non-AF-stroke (n = 53), and non-AF-non-stroke (n = 53). All subjects underwent cardiac computed tomography examination. Myocardial thickness at the LA-LAA junction was measured, and radiomics features were extracted. Radiomics features included first-order statistical features, shape features, and texture features. Least Absolute Shrinkage and Selection Operator (LASSO) regression was used to screen features, and a logistic regression model combining radiomics features and clinical parameters was constructed. Group comparisons were performed using t-tests or Mann-Whitney U tests. The predictive ability of the model was evaluated with the receiver operating characteristic (ROC) curve, and a nomogram was used for risk assessment.

RESULTS

Compared with AF patients without stroke, patients with AF-related cardioembolic stroke significantly increased myocardial thickness at the LA-LAA junction [7.1 (6.43-8.33) mm vs. 6.58 ± 1.45 mm, p < 0.05]. In addition, multivariate logistic regression demonstrated that myocardial thickness was independently associated with AF-related cardioembolic stroke. Three radiomics features were selected by LASSO regression in AF-related cardioembolic stroke and non-AF-non-stroke patients, and a radiomics score (Rad-score) was generated. The Rad-score was statistically significant between the groups (p < 0.001). The combined model incorporating Rad-score and clinical parameters achieved an area under curve (AUC) of 0.968 in the test cohort.

CONCLUSION

Both myocardial radiomics features and myocardial thickness at the LA-LAA junction may serve as potential imaging markers associated with AF-related cardioembolic stroke. Their incremental value for stroke risk stratification beyond established clinical risk factors requires further validation in larger prospective cohorts.