Assessment of myocardial bridge anatomy and ischemia with an integrated protocol combining coronary CT angiography and dynamic CT myocardial perfusion imaging

Abstract Objective: This study explored the adoption of adenosine-stress dynamic computed tomography-myocardial perfusion imaging (CT-MPI) to assess hemodynamic changes in patients with left anterior descending myocardial bridge (MBs). Materials and Methods: A total of 52 patients with left anterior descending MBs and 27 controls were retrospectively included in this study to investigate the differences in myocardial blood flow (MBF), CT-fractional flow reserve (CT-FFR), and ΔCT-FFR. Results: A total of 52 patients with left anterior MBs and 27 controls were included in this study. The CT-FFRsystole of patients in the MB group was significantly lower than that in the control group (median [interquartile range], 0.73 [0.55–0.80] vs. 0.82 [0.72–0.86]; P = 0.005). The ΔCT-FFRsystole in the MB group was significantly higher than that in the control group (0.26 [0.13–0.38] vs. 0.18 ± 0.10; P =0.022). However, there was no statistically significant difference in MBF in the left anterior descending artery territory between the MB and control groups (143.08 [118.21–168.03] mL/g/min vs. 149.74 ± 28.11 mL/g/min; P = 0.301). Conclusions: Left anterior descending MBs may lead to anatomic compression and significant changes in CT-FFR and ΔCT-FFR of the left anterior descending artery. However, MBF in the left anterior descending artery territory as quantitatively assessed by adenosine-stress dynamic CT-MPI was not reduced in these patients, which suggests that the CT-FFR and ΔCT-FFR findings overestimated the hemodynamic changes caused by the left anterior descending MBs.