Contrast studies were not performed because of previous thyroid disorder and planned contrast-enhanced MRI and MRA will follow.
There is a hyperdense lesion in the right middle cerebellar peduncle with surrounding hypoattenuation extending into the right cerebellar hemisphere and pons.
A small speck of calcification is situated immediately posteroinferior to the hyperdense lesion. There is associated mass effect, with expansion of the right middle cerebellar peduncle and partial effacement of the fourth ventricle. No hydrocephalus.
A tubular, serpiginous hyperdense structure coursing through the right cerebellopontine angle cistern and along the inferior margin of the lesion is in keeping with a prominent vessel.
A hyperdense mass adjacent to right anterior clinoid process.
No further intracranial hemorrhage detected. No evidence of acute ischemia. No calvarial abnormality. The imaged paranasal sinuses and mastoid air cells are clear.
Conclusion:
Right middle cerebellar peduncle hemorrhage is favored to represent hemorrhage due to an underlying AVM/AVF or cavernous malformation. Less likely differential diagnoses include hemorrhagic metastasis or hypertensive hemorrhage. Suspect Right ICA aneurysm adjacent to anterior clinoid. MRI/MRA is recommended for further evaluation.