PLAT and Dilatation of the cerebral artery: Because the presence of an intracranial aneurysm is contraindicated to r-tPA (and because the earlier the r-tPA is administered, the more favorable is the outcome of recovery), physicians struggle with the dilemma of performing either CT or magnetic resonance (MR) angiography to exclude the possibility of intracranial aneurysms, or shortening the interval between the onset of stroke and the application of r-tPA but omitting this contraindication.