Revisiting right anterior oblique projections for the triangle of Koch: implications from computed tomography

摘要

a-f Determination of Orientation of the Triangle of Koch (TK) and coronary sinus ostium (CSo) using CT imaging. a A multiplanar reformation CT image of the TK based on right atrial anatomical landmarks. Cross-sections (blue dotted lines labelled with Sections b-f) represent to typical CT axial imaging planes used to analyze TK (upper and lower) and CSo orientations, with the corresponding images shown in figures b-f. b Apical border of the TK visualized in the axial plane by the appearance of the CFB (red arrow). c Lower border of the TK identified in the axial plane by the appearance of the CSo bottom (red arrow), which separates the right atrium (RA) and CS (blue arrows). d and e Upper and lower TK sections. The orientation of the upper (ANGupper) and lower (ANGlower) TK is determined by the angle between the line connecting the anterior (ER) and posterior (TVA) boundaries of the triangle and a line drawn to the horizontal plane (blue lines). f CS section. The direction of the CSo (ANGCS) is determined by the angle between the CSo, which is determined by the line connection the anterior and posterior boundaries of the CSo, and the horizontal plane. The blue arrows show the course of the CS. AO, aorta; CFB, central fibrous body; ER, Eutachian ridge; LA, left atrium; RA, right atrium; RV, right ventricle; TVA, tricuspid valve attachment