Diagnostic values of inferior Q-waves for myocardial scar identification detected by 3.0 T cardiac MRI.

While Q-waves in inferior leads, particularly lead III, can be regarded as a minor abnormality, it can also indicate the presence of myocardial scar. This study assessed the diagnostic value of pathologic inferior Q-waves (lead II, III, aVF) for detecting ischemic scars using a high-resolution 3.0 T cardiac magnetic resonance (CMR). We retrospectively analyzed 1692 patients with suspected or known coronary artery disease who underwent stress CMR perfusion or viability assessment. Pathologic Q-waves were defined as duration of ≥ 30 ms and depth of ≥ 1 mm or QS-complex. Eleven models were created to evaluate the presence of Q-waves in different combinations of inferior leads. Of the 1692 patients, 436 (25.8%) had pathologic Q-waves. Models with Q-waves in leads II + aVF (model 7) and II + III + aVF (model 9) showed high specificity (100% and 99.6%), positive predictive value (PPV) (80.0% and 86.7%), and negative predictive value (NPV) (82.6% and 84.3%) but low sensitivity (1.3% and 13.1%). Other models also maintained high specificity and NPV but poor sensitivity and PPV. Notably, 21% of patients with an isolated pathologic Q-wave in lead III (model 4) exhibited scars. These findings highlight the need for careful clinical assessment when pathologic Q-waves are present.

Reference values of myocardial native T1 and extracellular volume in patients without structural heart disease and had negative 3T cardiac magnetic resonance adenosine stress test.

Background: To establish the reference values of native T1 and extracellular volume (ECV) in patients without structural heart disease and had a negative adenosine stress 3T cardiac magnetic resonance. Methods: Short-axis T1 mapping images were acquired using a modified Look-Locker inversion recovery technique before and after administration of 0.15 mmol/kg gadobutrol to calculate both native T1 and ECV. To compare the agreement between measurement strategies, regions of interest (ROI) were drawn in all 16 segments then averaged to represent mean global native T1. Additionally, an ROI was drawn in the mid-ventricular septum on the same image to represent the mid-ventricular septal native T1. Results: Fifty-one patients (mean 65 years, 65 % women) were included. Mean global native T1 averaged from all 16 segments and a mid-ventricular septal native T1 were not significantly different (1221.2 ± 35.2 vs 1228.4 ± 43.7 ms, p = 0.21). Men had lower mean global native T1 (1195 ± 29.8 vs 1235.5 ± 29.4 ms, p < 0.001) than women. Both mean global and mid-ventricular septal native T1 were not correlated with age (r = 0.21, p = 0.13 and r = 0.18, p = 0.19, respectively). The calculated ECV was 26.6 ± 2.7 %, which was not influenced by either gender or age. Conclusions: We report the first study to validate the native T1 and ECV reference ranges, factors influencing T1, and the validation across measurement methods in older Asian patients without structural heart disease and had a negative adenosine stress test. These references allow for better detection of abnormal myocardial tissue characteristics in clinical practice.