The first test is an urgent CT of the head without contrast to exclude intracranial hemorrhage or other neurosurgical emergencies that are a contraindication to thrombolytic therapy. Please note that a CVA typically takes 24 hours or so to become manifest on CT, therefore a follow-up CT in several days may be useful to define stroke anatomy and extent if the patient goes on to a completed CVA. MRI is not generally needed to evaluate acute CVA, but may be requested by subspecialty clinicians. An excellent follow-up examination is a carotid ultrasound to attempt to define the cause of the patient's neurological symptoms and identify a potentially treatable lesion and avoid further episodes.