Clinical presentation: A 72-year-old patient is brought to the emergency room with a left-sided hemiparesis. The symptoms occurred about 5 hours ago. Pre-existing conditions: Arterial hypertension, Type 2 diabetes mellitus Question: Intracranial hemorrhage? Infarct? A non-contrast CT was performed.

Here is a summary of the expert findings:

The patient had an ischemic stroke due to occlusion of the basilar artery. The intermittent dizziness, which had already occurred the day before, is to be considered central vertigo and a sign of ischemia of the posterior circulation. With a pronounced neurological deficit (NIHSS ≥ 6), absence of infarct evidence in non-contrast CT (= pc-ASPECTS [...]

In the case of detecting a perimesencephalic subarachnoid hemorrhage in the non-contrast CT, a CTA is recommended to investigate for possible aneurysmal cause. In case of a negative CTA, it remains controversial whether an additional DSA makes sense. MRI is performed if the diagnostic angiography is unremarkable. MRI can exclude further causes of bleeding (e.g., cerebral amyloid [...]