BACKGROUNDInvasive intravascular ultrasound (IVUS) is current diagnostic standard for myocardial bridging (MB). Non-invasive multislice computerized tomography coronary angiography (MSCT) technique has provided a good anatomical view of the tunnel artery now.

METHODSA total of 51 consecutive patients with atypical or typical angina scheduled for IVUS were enrolled in this study and MSCT was performed 7 days before IVUS. Coronary imaging was quantified using IVUS and MSCT. Four main vessels (left main artery (LMA), left anterior descending (LAD), left circumflex (LCX), right coronary artery (RCA)) were examined.

RESULTSForty-one out of 51 (80%) patients received metaprolol (25 mg) before the MSCT scan and 25 of them were current beta-blocker users. The mean heart rate was (64 +/- 3) beats per minute. A total of 51 patients underwent IVUS examination (30 with MB and 21 without MB) were chosen for this study. Twenty-eight out of 30 MB cases were correctly diagnosed by MSCT and 2 patients with MB were not detected. Comparison with IVUS, the sensitivity of detection by MSCT was 93%, specificity was 100%. The lumen diameter of the tunnel artery derived from MSCT and IVUS significantly decreased from (2.9 +/- 0.3) mm to (2.4 +/- 0.4) mm (P < 0.001) and from (3.3 +/- 0.3) mm to (2.6 +/- 0.5) mm (P < 0.001), respectively. Minimal and maximal diameters of MB derived from MSCT were significantly smaller than those from IVUS ((2.4 +/- 0.4) mm vs (2.6 +/- 0.5) mm, P < 0.05 and (2.9 +/- 0.3) mm vs (3.3 +/- 0.3) mm, P < 0.05), respectively.

CONCLUSIONSMSCT offers a reliable non-invasive method for MB in LAD and atherosclerosis diagnosis with diagnostic accuracy comparable with invasive IVUS.