Abstract 4211: Depth of Myocardial Bridges on Computed Tomographic Angiography is Associated with Myocardial Perfusion Defects on Single Photon Emission Computed Tomography

Although considered a relatively benign congenital coronary anomaly, myocardial bridges have been associated with myocardial ischemia, infarctions, and sudden cardiac death. The aim of this study was to identify characteristics of myocardial bridges on computed tomographic angiography (CTA) associated with abnormal defects on myocardial perfusion imaging (MPI). A retrospective study was performed to identify patients who had myocardial bridges detected by 64-slice multidetector cardiac CTA and prior stress single photon emission computed tomography (SPECT) MPI. Using axial, oblique, and curved multi-planar reformatted images, myocardial bridge characteristics, including length and maximum depth of the tunneled segments, were compared in patients with and without corresponding coronary perfusion defects on SPECT MPI. From a total of 272 patients who had both SPECT MPI and cardiac CTA performed, 23 patients (8%, males= 9, mean age= 57 years) were identified with myocardial bridges. The left anterior descending artery was the predominant affected coronary artery (20/23, 87%). Eight patients (35%) with myocardial bridges had corresponding perfusion defects on SPECT MPI. Increased depth of the tunneled segment was significantly associated with abnormal SPECT MPI compared to normal SPECT MPI (4.1 ± 2.0mm vs. 1.9 ± 0.9mm, respectively, p< 0.002). The length of the tunneled segment did not differ in patients with or without abnormal SPECT MPI (27.8 ± 15.6mm vs. 20.9 ± 12.6mm, respectively, p=0.26). This is the first study to correlate SPECT MPI and 64-slice multidetector cardiac CTA in the evaluation of myocardial bridges. Increased maximum depth of the tunneled segment on cardiac CTA is significantly associated with myocardial perfusion defects.