Final answer:
A CT scan should be performed for a patient with a suspected stroke within 25 minutes of arrival at the hospital, as it can rapidly detect bleeding or other abnormalities in the brain.
Step-by-step explanation:
For a patient with suspected stroke, a Computed Tomography (CT) scan should be performed within 25 minutes of hospital arrival. The CT scan is a type of X-ray that can quickly identify bleeding in the brain or other significant abnormalities, which is vital for the appropriate management of stroke patients. Early intervention with treatments such as aspirin therapy, which aims to prevent blood clot formation, may be initiated based on the rapid assessment of neurological function and the findings of the CT scan. Other tests, like Magnetic Resonance Imaging (MRI), Electroencephalogram (EEG), and Lumbar Puncture are not the primary emergency investigations for an acute stroke, as they either require more time or are indicated under specific conditions that the CT scan might later suggest.