Degeneration: 4D CT (short axis)

Typical appearance of bioprosthetic degeneration on short-axis 4D CT. This patient presented with acute pulmonary embolism 19 years post-tricuspid valve replacement. The leaflets were calcified, with signal intensity similar to that of the sewing ring and bony structures. The valve is essentially immobilized in a semiclosed position, resulting in both severe stenosis and severe regurgitation. The apparent valve opening in the short-axis 4D CT images is due to through-plane motion (the valve moving through the imaging plane).