1. Using neurofilament light chain as a diagnostic tool and predictor of outcome of acute ischemic stroke
2. Using neurofilament light chain in detecting severity in old ischemic stroke

Ischemic stroke is the second leading cause of death and disability with symptoms ranging from complete remission within 24 h (transient ischemic attack, TIA) to lasting disability in the form of cognitive dysfunction, physical disability, and complete dependency on others. The currently available acute treatments of intravenous administration of tissue plasminogen activator (2) and mechanical thrombectomy are associated with rare but severe side effects such as hemorrhage of the brain and body. Because these treatments require rapid initiation to be effective, some patients may be exposed to side effects without benefiting from the treatment. We need, therefore, to identify biomarkers that can predict functional outcome, especially in the early phases, and improve our understanding of the pathophysiological mechanisms underlying tissue damage following a stroke to develop new advanced therapeutic strategies.

When brain damage occurs, neuronal injury and disruption of axonal membranes lead to the release of cytoskeleton proteins, such as neurofilaments (NFs), into the interstitial fluid and eventually into the cerebrospinal fluid (CSF) and blood. NFs are highly specific structural, neuronal cytoskeletal proteins that consist of four NF subunits: NF light (NF-L), NF medium (NFM), and NF heavy (NF-H) chains, and alpha-internexin.

NF-L has been studied as a potential CSF and circulation biomarker for a wide range of neurological disorders (3), including cerebral small vessel disease (4) and subacute ischemic stroke.

The inflammatory process that ensues after a stroke destabilizes the blood-brain barrier (BBB) and contributes to neuro-axonal damage, thereby increasing the release of NFs and glial and inflammatory markers into the CSF and blood.

Ischemic stroke has recently been shown to cause persistent elevations in serum NF-L that correlated with infarct volumes and recurrent ischemic lesions.

So, Measuring serum level of NF-L will be promising as a biomarker for predicting severity of stroke symptoms and its functional outcome. So, we can predict prognosis of these cases.

NF-L levels obtained within 24 h of symptom onset in the blood of ischemic stroke and TIA patients will be associated with diagnosis of these patients and as a predictor for functional outcome of these patients.

These patients after 1 and 3 months will be assessed again clinically by NIHSS and mRS to assess their outcome and detecting possibility of recurrence.

the investigators will also measure serum NF-L levels in old ischemic stroke patients having stroke of 6 to 12 month duration, as NF-L will be used as a predictor of severity of ischemic stroke in these patients.

the investigators will also measure NF-L in healthy controls to compare its level between the healthy and diseased cases.

the investigators will also measure infarct size in MR imaging, measure media-intima thickness of carotid artery, and correlate their findings with NF-L serum level to predict stroke severity and functional outcome.

Inclusion Criteria:

• both sex
• Age between 18 to 70 years old.
• symptoms suggestive of acute ischemic stroke: presenting within 24 hours of onset of these symptoms
• for chronic ischemic patients : Duration of 6 to 12 month of development of ischemic symptoms
• for control cases : Healthy people

Exclusion Criteria:

• presence of space occupying lesion
• presence of sinus thrombosis
• presence of hemorrhagic stroke
• presence of sub-arachnoid hemorrhage
• presence of Alzheimer disease, Parkinson disease, multiple sclerosis, amyotrophic lateral sclerosis, or traumatic brain injury

population will include 3 groups, group A : will include patients of acute ischemic stroke - developing focal neurological symptoms in first 24 hour - of age between 18 - 70 year old.

group B : will include patients of chronic ischemic stroke - developing focal neurological symptoms for 6-12 month - of age between 18 - 70 year old. group C : will be healthy controls of age above 18 y.o