he myocardial bridge (MB) is an anatomical variant that often covers part of the left anterior descending coronary artery (LAD). 1 It occurs almost exclusively in the mid-portion of the LAD (Figure 1). 2,3 Muscular contraction of the MB itself alters blood flow within the LAD, as demonstrated by coronary angiography, and influences the distribution of hemodynamic stress. [3][4][5] It is widely accepted that an MB sometimes causes coronary heart disease (CHD), 2,5,6 either from direct compression of the MB at cardiac systole or by enhancement of the natural progression of coronary atherosclerosis in the LAD segment proximal to the MB. 2,5,7 Both mechanisms are closely associated with changes in hemodynamic stress driven by the force of the MB contraction through a combination of anatomical properties, such as the location, length, and thickness of the MB. 3,7,8 This review focuses on the relationship between the presence of an MB in the LAD and the occurrence of CHD, specifically addressing the importance of the anatomical properties of the MB as the common root for the 2 distinct mechanisms. In addition, therapeutic approaches to CHD caused by an MB are summarized, along with their outcomes. A myocardial bridge (MB), partially covering the coronary artery, is a congenital anatomical variant usually present in the left anterior descending coronary artery (LAD). MB causes coronary heart disease (CHD) by 2 distinct mechanisms influenced by the anatomical properties of the MB, such as its length, thickness, and location. One is direct MB compression of the LAD at cardiac systole, resulting in delayed arterial relaxation at diastole, reduced blood flow reserve, and decreased blood perfusion. The other is enhancement of coronary atherosclerosis causing stenosis of the LAD proximal to the MB, occurring because of endothelial injury arising from the abnormal hemodynamics provoked by retrograde blood flow up toward the left coronary ostium at cardiac systole. The magnitude of the effect of the 2 distinct mechanisms of the MB on LAD blood flow is prescribed by a common root of the MB-muscle mass volume generated by those properties. Furthermore, the anatomical properties of the MB are closely associated with the choice of treatment and therapeutic outcome in CHD patients having an MB. Thus, the anatomical properties of an MB should be considered in the diagnosis and management of CHD patients with this anomaly. (Circ J 2011; 75: 1559 - 1566

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Low-grade fibromyxoid sarcoma (LGFMS) is a rare tumor that commonly arises in the lower extremities but rarely in the mesentery. We report computed tomography (CT) and magnetic resonance imaging (MRI) findings of LGFMS of the small bowel mesentery. On CT, the mass was composed of two components. One component, on its right side, appeared to have isointense attenuation relative to muscle, whereas the other component, on its left side, appeared to have low attenuation. On MRI the mass on the right side showed hypointensity similar to muscle on both T1-and T2-weighted images as well as mostly slight enhancement on contrast-enhanced T1-weighted images. On the other hand, the mass on the left side showed relative hypointensity on T1-weighted images and hyperintensity on T2-weighted images as well as intense enhancement on contrast-enhanced T1-weighted images, suggesting that the tumor contained myxoid tissue. The myxoid area of LGFMS may have a tendency to reveal intense enhancement on contrast-enhanced images.