Final answer:
X-ray angiography is the imaging technique that measures the speed and amount of blood flow in acute stroke cases.
Step-by-step explanation:
The imaging technique that measures the speed and amount of blood flow through blood vessels in acute stroke cases is X-ray angiography. X-ray angiography uses a contrast dye injected into the blood vessels, followed by X-ray imaging to visualize the flow of the dye. This technique allows doctors to identify blockages or abnormalities in the blood vessels of the brain, which can help guide treatment decisions.