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Introduction Myocardial properties can be quantitatively evaluated using myocardial native T1 values (nT1) obtained using cardiac magnetic resonance imaging (CMR). In terms of myocardial wall thickness, the left ventricular nT1 is easy to measure, but the right ventricular nT1 is difficult. Patients with congenital heart disease often develop right ventricular overload. If right ventricular nT1 can be measured consistently, inflammation and fibrosis of the right ventricular myocardium can be quantitatively evaluated. We aimed to determine whether T1 mapping during systole can be used to evaluate right ventricular myocardial properties. Methods T1 mapping was performed at diastole and systole. Systolic T1 mapping was calculated from diastolic T1 mapping and cine images. The myocardial properties of both ventricles were evaluated in 13 healthy volunteers (21-26 years old) and 12 patients with right ventricular overload (12-41 years old) who underwent CMR examination at our hospital. Results From the analysis of left ventricular nT1, we found that nT1 did not change significantly during the cardiac cycle. However, right ventricular nT1 changed between diastole and systole because the right ventricle is affected by blood. Although there was no difference in right ventricular diastolic nT1 between the patients and volunteers (1,346.8 vs. 1,347.6 ms, p = 0.852), the right ventricular systolic nT1 was significantly higher in patients than in volunteers (1,312.7 vs. 1,233.8 ms, p = 0.002). This indicates that right ventricular myocardial damage occurs in patients with right ventricular overload. Conclusion Systolic right ventricular myocardial T1 mapping allows assessment of right ventricular myocardial properties. The right ventricular myocardial systolic nT1 is useful for evaluating myocardial damage due to right ventricular stress and myocardial injury. Measuring right ventricular nT1 may allow consideration of early therapeutic intervention., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Asahikawa Medical University Ethics Board issued approval 21163. This study was conducted in compliance with the standards of the Declaration of Helsinki and the current ethical guidelines and was approved by our institutional ethics board. Written informed consent to participate was obtained from all the participants. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Sasaki et al.)

Objectives: To investigate the measurement discrepancy of coronary computed tomography angiography (CTA)-derived fractional flow reserve (FFR) between diastolic (CT-FFR-D) and systolic (CT-FFR-S) phases using FFR as the reference standard.Methods: Participants, suspected of coronary artery disease and indicated for invasive coronary angiography (ICA) and FFR and coronary CTA and CT-FFR, were enrolled in this study (Clinicaltrials.gov:NCT03692936) from September 2018 to October 2019. For every participant, coronary CTA of both systolic and diastolic phases was postprocessed to calculate CT-FFR-S and CT-FFR-D, respectively. Diagnostic sensitivity, specificity, accuracy, and the area under the receiver operating characteristic (ROC) curve were compared.Results: A total of 181 lesions from 151 participants (mean age 54.5 ± 7.8 years, 113 males) were analyzed. Of these, 129 lesions from 110 participants were successfully measured both in diastolic and systolic phases. Sensitivity, specificity, and accuracy of CT-FFR-D and CT-FFR-S on per-patient level were 88.9%, 91.3%, 90.1% and 66.7%, 87.7%, 76.7%, on per-vessel level were 89.5%, 91.5%, 90.6% and 66.7%, 87.0%, 77.9%, respectively. The ROC curve of CT-FFR-D was significantly higher than that of CT-FFR-S on both per-patient and per-vessel levels (0.938 vs. 0.771, 0.935 vs. 0.772, both p < 0.0001). In severe hemodynamic lesions (FFR ≤ 0.7), the absolute difference between CT-FFR-S and FFR was significantly higher than that between CT-FFR-D and FFR [0.1636, inter-quartile range (IQR): 0.0662-0.2586 vs. 0.0953, IQR: 0.0496-0.1702, p = 0.035].Conclusion: CT-FFR derived in diastole was superior to that derived in systole in detecting coronary ischemic lesions. For lesions with FFR < 0.7, CT-FFR measured in the diastolic phase was noted to be more closely approximated to FFR. [ABSTRACT FROM AUTHOR]