Feasibility of 12-lead ECG reconstruction at rest and during adenosine stress perfusion inside a 3-Tesla MR scanner.

Background Electrocardiographic (ECG) devices in magnetic resonance (MR) scanners have a narrow bandwidth and suffer from signal distortion, preventing measurement of QRS/ QT durations, or detection of ST/ T-wave changes during ischaemia. We integrated an external device with novel post-processing software into a 3 Tesla (T) scanner to assess feasibility and accuracy for reconstructing 12-lead ECGs prior to and during adenosine infusion. Methods Reference 12-lead ECGs were first recorded outside the MR-environment. Using three MR-safe electrode patches, in-bore ECGs were then recorded prior to and during adenosine infusion. Post-processing removed artefacts and 12-lead ECGs were reconstructed from the raw signal using a subject-specific matrix. In-bore and reference ECGs were compared using Pearson's correlation coefficient on the PQRST waveform and by manual measurements of QRS and QT durations. Adenosine-induced ischaemic changes were compared with corresponding territories on stress perfusion maps. Results In 26 participants (70.8 ± 13.0 years; 34.6% female), in-bore ECGs were recorded without additional scan time. Reconstruction took < 2 min per participant. In-bore and reference ECGs were strongly correlated (r = 0.81, interquartile range 0.72-0.88), and mean differences in QRS and QT durations were small (-12.5 ms [95% limits of agreement - 42.5, 17.5 ms], and - 5.5 ms [-54.6, 43.6 ms] respectively). Ischaemic ECG changes during adenosine predicted stress myocardial blood flow (MBF) < 1.75 ml/g/min with sensitivity 91.7% (95% confidence interval 66.7, 100.0), specificity 59.3% (39.6, 77.6), positive predictive value (PPV) 33.3% (11.4, 57.7), negative predictive value (NPV) 97.0% (90.0, 100.0) and area under curve 0.74 (0.61, 0.86). Conclusion In this proof-of-concept study, in-bore ECGs correlated closely with reference ECGs. In-bore ECGs during stress perfusion have high specificity and NPV, but low sensitivity and PPV for predicting stress MBF < 1.5 ml/g/min. This may hold value for improving R-peak detection, patient monitoring and stress perfusion map interpretation.