New Definition of TIA
"a sudden neurological deficit of presumed vascular origin lasting less than 24 hours."
a transient episode of neurological dysfunction caused by focal brain, spinal-cord, or retinal ischemia, without acute infarction.
Stroke. Published online May 7, 2009.
Patients with suspected TIA should be evaluated as soon as possible after an event, preferably with a diffusion-weighted or perfusion-weighted MRI.