Basilar Aneurysm - Case 3

A 45 year-old woman developed headaches followed by a right hemiparesis and a right fourth nerve palsy.

                  Outline the Aneurysm                                                                         Outline the Left Pontine Infarction

Axial MRI scan. (Left) T1-weighted image; (Right) T2-weighted image. Note the circular mass compressing the upper pons (yellow arrows). Look closely at the T2 weighted image and note the abnormal signal in the left pons. This is an infarction of the basis pontis that resulted in the right hemiparesis. The circular mass is a fusiform basilar aneurysm. Although aneurysms typically come to clinical attention by bleeding, rarely they will enlarge and result in a mass lesion..

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