Here is a free full text review in CCJM.
TIA may be going the way of unstable angina in that its numbers are diminishing. That does not mean the true incidence is decreasing. Today's testing is more sensitive in detecting tissue damage. This reclassifies many cases of unstable angina to MI. Likewise many cases formerly called TIA are now known to be strokes. New diagnostic techniques bring new definitions.
Traditional definition of TIA: The sudden onset of a focal neurologic deficit in a vascular territory resolving within 24 hours.
New definition: Same as above but with no evidence of acute infarction on diffusion weighted MRI.
The review covers imaging and stroke prevention strategies.