MRCP diagnosis of Mirizzi syndrome in a paediatric patient: importance of T1-weighted gradient echo images for diagnosis.

We report a 15-year-old boy with Mirizzi syndrome diagnosed by MR cholangiopancreatography (MRCP). Respiratory-triggered 3D MRCP was performed during free breathing. An impacted gallstone was noted in the infundibulum; this was not visible on T2-weighted images, but was hyperintense on T1-weighted gradient-echo images. This case illustrates the utility of 3D MRCP with parallel imaging in paediatric patients and the importance of T1-weighted gradient-echo images for the diagnosis of impacted gallstones.