الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 162 |  |  |
| | | from | 162 | | |
Abstract
Recent advances in neuroimaging have enhanced the understanding
of TIA. Accumulated evidence indicates that clinically transient
manifestations are not transient at the tissue level and leave infarction in
the brain in about half of TIA patients. TIA-related acute infarcts are
typically extremely small and often are not detected by CT and
conventional MRI. Diffusion-weighted imaging (DWI) is currently the
preferred method of imaging in TIA. Recognition of acute infarcts in
patients with TIA has challenged the long standing conventional
definition and led to the proposition of a new tissue-based definition. The
tissue based definition reserves the term TIA for transient episodes
without radiological evidence of acute infarction. So that “TIA with DWI
related lesions” represents an extremely unstable condition with early risk
of stroke that is higher than the risk after TIA with normal imaging.
The persons of this study were classified in to 2 groups; patients
group (Ι) and control one (Π). The patients group (Ι) was divided in to 2
subgroups:
1-Group (ΙA): (n=35) were those clinically diagnosed to have a
recent TIA for the first time for whom initial DW-MRI scans
were done within 48 hr from TIA onset and a follow up one 3
months later for those with initial positive DWI.
2- Group (ΙB): (n=35) were those clinically diagnosed to have a
recent ischemic cerebro-vascular stroke with past history of TIAs
during the last one year.
In group (ΙA), it was found that those with TIA duration ≥1 hour, having
mainly AF and /or carotid artery stenosis > 50% and clinically presented
with aphasia and/or motor manifestations were associated with lesions on
Summary
105
DWI and the combinations of two or more previous parameters were
associated with irreversible lesions on follow up DWI done 3 months
later from the initial ones.
In group (ΙB), it was found that most of the clinical presentations
of the acute ischemic strokes were similar to that of prior TIAs whom
those patients had during the last one year with ipsilateral hemispheric
involvement. It was also found that DWI done during development of
evident ischemic stroke detected permanent ischemic lesions
corrosponding to the prior TIAs manifestations in 8 patients (22.85 %).
Those with prior TIAs duration ≥ 1 hour , having mainly AF and /or
carotid artery stenosis > 50% as risk factors and clinically presented
with aphasia and/or motor manifestations , had positive DWI for their
prior TIAs more than those with negative scans.