Pseudocalculus sign (common bile duct)
A pseudocalculus sign is a term coined to describe a mimic of a distally impacted common bile duct stone on MRCP and CT cholangiography.
It results from the forceful contraction of ampulla of Vater with secondary pouting into the lower end of the CBD. This impression is superiorly rounded and may appear as the superior surface of a stone, leading to the misdiagnosis of choledocholithiasis.
- 1. Lin Eugene, Kavita Garg, Edward Escott et al. Practical Differential Diagnosis in CT and MRI. Thieme, 2008. ISBN: 1588906558, 9781588906557.