If stroke like symptoms were caused by cervical artery dissection, would this show up in mrv and mri of brain. or only a scan of neck?

Depends on timing: A CT or MRI can detect changes of edema (fluid) due to cell death within the brain. Often by the time these changes are seen, it is late in the process. Also this would tell us the arterial territory involved, but not that it is a result of dissection. Emboli or thrombus of an artery are more common causes of stroke. A carotid dissection is less common, though more common in vertebral artery.