Korean Circ J.  2008 Nov;38(11):583-589. 10.4070/kcj.2008.38.11.583.

An Overview of Myocardial Bridging With a Focus on Multidetector CT Coronary Angiographic Findings

• Ko SM

• KMID: 2225705
• DOI: http://doi.org/10.4070/kcj.2008.38.11.583

Abstract

Myocardial bridging (MB) is a common anatomical variant rather than a congenital anomaly, and it is usually considered benign. It is generally confined to the mid-portion of the left anterior descending coronary artery. Atherosclerotic plaques are often located in the segment proximal to the bridged segment, although the tunneled segment is typically spared. Conventional coronary angiography is the gold standard for detection, but it is invasive and may not be sensitive enough to detect a thin bridge. The prevalence of MB reported in multidetector CT (MDCT) coronary angiographic series has ranged from 3.5% to 30.5% in patients with chest pain or with suspected or known coronary artery disease. Today, MDCT coronary angiography is an alternative noninvasive imaging tool that allows for easy and accurate evaluation of MB.

Keyword

Coronary arteries; Myocardial bridging; Computerized tomography

MeSH Terms

Chest Pain
Coronary Angiography
Coronary Artery Disease
Coronary Vessels
Humans
Myocardial Bridging
Plaque, Atherosclerotic
Prevalence

Figure

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  Fig. 1 A 36-year-old man presented with chest pain for 2 weeks. A and B: (A) Short-axis MIP and (B) curved MPR images clearly depict a deep MB segment in the middle segment of the LAD (arrow). C and D: CCA shows that the lumen of the middle segment of the LAD (arrows) is compressed by myocardial contraction in the systolic phase (C), but recovers its normal diameter in the diastolic phase (D). The coronary tree shows no angiographic signs of coronary atherosclerosis. MIP: maximum intensity projection, MPR: multiplanar reconstruction, MB: myocardial bridging, LAD: left anterior descending coronary artery, CCA: conventional coronary angiography.

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  Fig. 2 Atherosclerotic stenosis proximal to MB in a 67-year-old man presenting with angina. A and B: (A) curved MPR and (B) VR images show a tunneled segment in the mid-LAD (arrows) and calcified plaques in the segments (arrowheads) proximal and distal to the MB, but not within the tunneled segment. C: CCA shows multifocal stenoses in the proximal and distal LAD and the diagonal branches (arrowheads), but no MB was detected in the mid-LAD (arrow). MPR: multiplanar reconstruction, MB: myocardial bridging, LAD: left anterior descending coronary artery, CCA: conventional coronary angiography, VR: volume-rendered.

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  Fig. 3 Hypertrophic cardiomyopathy in a 66-year-old woman who presented with chest pain on exercise. A and B: (A) short-axis MIP and (B) curved MPR images show the intramyocardial course of the mid-LAD (arrows) and asymmetric wall thickening, mainly in the septum and anterior wall of the left ventricle. MIP: maximum intensity projection, MPR: multiplanar reconstruction, LAD: left anterior descending coronary artery.

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  Fig. 4 A 76-year-old woman who underwent MDCT for evaluation of the patency of a coronary artery bypass graft. (A) Curved MPR and (B) VR images show a short segment in the middle part of the LAD (arrows) encased by myocardium, along with a patent left internal mammary artery-LAD graft (arrowheads) proximal to the MB segment. MDCT: multidetector CT, MPR: multiplanar reconstruction, MB: myocardial bridging, LAD: left anterior descending coronary artery, VR: volume-rendered.

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  Fig. 5 A 46-year-old man presented with intermittent chest pain. (A) Curved MPR and (B and C) short-axis MIP images show two MBs in the mid-segment (arrows) and distal segment (arrowheads) of the LAD. MPR: multiplanar reconstruction, MIP: maximum intensity projection, MB: myocardial bridging, LAD: left anterior descending coronary artery.

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  Fig. 6 A 50-year-old man presented with atypical chest pain. (A) Axial MIP and (B) curved MPR images show a superficial MB segment in the mid-LAD (arrows). MIP: maximum intensity projection, MPR: multiplanar reconstruction, MB: myocardial bridging, LAD: left anterior descending coronary artery.

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  Fig. 7 A 73-year-old man presented with atypical chest pain. A and B: (A) short-axis MIP and (B) curved MPR images show a deep MB segment in the mid-LAD (arrows). C: VR image clearly demonstrates a deep MB (arrow) in the mid-LAD. MPR: multiplanar reconstruction, MIP: maximum intensity projection, MB: myocardial bridging, LAD: left anterior descending coronary artery, VR: volume-rendered.

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  Fig. 8 A 54-year-old man presented with atypical chest pain. (A) Axial MIP and (B) curved MPR images show a "right ventricular" type of MB segment in the mid-LAD (arrows). MPR: multiplanar reconstruction, MIP: maximum intensity projection, MB: myocardial bridging, LAD: left anterior descending coronary artery.

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  Fig. 9 Phasic luminal change in the MB using dual-source CT in a 22-year-old man with angina. A: short-axis MIP image shows a deep MB over the mid-segment of the LAD (arrow). B and C: systolic and diastolic VR images show that the lumen of the middle LAD (arrows) is compressed by myocardial contraction in the systolic phase (B), but recovers its normal diameter in the diastolic phase (C), a phenomenon known as the "milking effect". MIP: maximum intensity projection, MB: myocardial bridging, LAD: left anterior descending coronary artery, VR: volume-rendered.

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