Detection of TIAs after the event.

To my limited knowledge, TIAs are caused by temporary blood clots in the brain. Because the effects of TIAs do not last longer than 24 hours, I'm presuming that TIAs do not injure the brain.

Obviously, this is wrong, as I've been told that TIAs can lead to dementia.

How do TIAs lead to dementia?

And how can TIAs be detected clinically, days or weeks after the blood clot has dissolved?

The other part of my question which I can't find anywhere on the net, is how Single Photon Emission Computed Tomography (SPECT) can be used to screen for dementia?

Thanks in advance,
Sn Ale

[CCF-Neuro-M.D.-JT]

TIA's are thought to be "reversible" neurological episodes that last less than 24 hrs due to atherosclerotic clots and are often but not always warning signs of an impending stroke. It is the strokes which cause permanent brain damage that can lead to dementia, not the TIAs. As the TIAs are reversible, there won't be any evidence of it clinically after 24hrs or on an MRI for that matter. If there is still some deficit, then it is now a stroke and no loner a TIA.

SPECT scans simply put measure blood flow to different regions of the brain. It's recently become a big research topic in evaluating patients with neurological diseases such as strokes, degenerative disorders, and dementia. Currently, we don't use it to screen patients for dementia at CCF. But in research studies, they've shown that there is reduced blood flow in specific regions of the brain that fit with certain types of dementia such as Alzheimer's disease.
Hope this helps.

[NgottMV]

Thanks you answered a question I've been asking around all over.
I was in the hospital last year.  They orginally took a CAT scan and said I had a  possible small stroke but it was really definiate.  After 4 days they took an MRI which didn't show any evidence of a STroke.  I have MVP with severe regurgitation.  so I am at risk for stoke.  I was told to take an ecotrin every day.  On currently seeing a cardiogist every 3 months for that condition. I was asking around if you had a MRI and had been on blood thinner by IV forgot the name of the medication it starts with an H and they take your blood every 6 hours.  I figured after the 4 days of blood thinners maybe the tiny clot disintergrated.  I had a droopy eye/face.  I was waking up with a heavy left arm in the morning.  One day my leg was heavy as well.

[Billb916]

I was diagnosed with a stroke 5 years ago.  When it happened the entire left side of the body was affected. My hearing, vison speech were all affected.  I was fortunate in that I was near a medical facility  and was put on medication within 25 minutes.  I did recover with minimal problems.  I was told by the Head of the neuro-emergency unit that I diffently had a stroke.  The MRI did not show major damage, but he pointed out what he called a "shotgun pattern" of small damaged areas - caused by a blood clot that had broke into several smaller pieces.  I have been taking Coumatin since this happened.

Interestily a recent review by a Neuro Surgeon here disputed whether I had a stroke.  He felt it really was a TIA.  So it is not always that clear what is a Storke and what isn't.