Antero-posterior Measurement
The presence of clot within the lumen can lead to errors in measurement.
Incorrect measurement
In this case, the antero-posterior measurement has been incorrectly assessed at 37.1 mm, whereas the aneurysm is actually around 60 mm in diameter.
This is a serious error, as the risk of rupture at 37.1 mm is considerably less than at 60 mm.
Correct measurement
In this case, the antero-posterior measurement has been correctly assessed at 64.9 mm.
Note that the lumen in this case is around 30 mm, and that the mural thrombus appears organised and stable.