Reconstruction of the four basic cardiac projections from magnetic resonance images: a new aspect

From 3D MR scans, the authors have constructed 2D "silhouettes" that correspond to standard radiographic views of the heart. These images explicitly demonstrate the relationship of the surface anatomy to the internal anatomy of the heart and serve to indicate what chambers contribute to the heart borders seen on radiographs. The findings depart from conventional wisdom in at least four respects, including: the left atrium contributes to the left heart border in a frontal radiograph in only a minority of subjects, in steep RAO and lateral radiographs, the right ventricle does not always form the anterior heart border, in left anterior oblique radiographs greater than 30 degrees, the anterior heart border is formed predominantly by the right ventricle, and the left ventricle extends more craniad along the posterior margin of the heart than expected.