Differentiating pannus from thrombus on cardiac CT
| Pannus | Thrombus | |
|---|---|---|
| Timing of presentation | Usually 12 months after surgery | Occurs at any time |
| Location | Below the aortic prosthesis | Above or below the aortic prosthesis |
| Morphology on CT | Circular mass extending from sewing ring Contrast enhancement Calcification may be present | Irregularly shaped mass attached to leaflet or hingepoint No contrast enhancement |
| CT attenuation | >145 HU | <145 HU |
HU, Hounsfield units.