NEURORADIOLOGY
ACUTE ISCHEMIC STROKE
Acute brain ischemia caused by arterial occlusion or critical hypoperfusion, with imaging aimed at excluding hemorrhage and defining salvageable tissue.
ANATOMY
Anterior circulation includes ICA, MCA and ACA territories.
Posterior circulation includes vertebral, basilar, PCA and cerebellar arteries.
Deep perforators supply basal ganglia, thalami and internal capsule.
PATHOLOGY
Thromboembolism or in-situ thrombosis reduces cerebral blood flow.
Early cytotoxic edema causes restricted diffusion before CT changes become obvious.
Large infarcts may develop edema, mass effect or hemorrhagic transformation.
CLINICAL PICTURE
Sudden focal deficit such as weakness, aphasia, neglect or visual loss.
Posterior circulation stroke may present with dizziness, diplopia, ataxia or reduced consciousness.
Time of onset and anticoagulation status guide urgent management.
RADIOLOGY FINDINGS
NCCT: hemorrhage exclusion, hyperdense vessel, early grey-white loss and sulcal effacement.
CTA: occlusion site, tandem lesion, stenosis and collateral status.
MRI/CTP: infarct core, mismatch and tissue at risk.
RECOMMENDATION
State hemorrhage status first.
Mention large vessel occlusion urgently.
Add ASPECTS for anterior circulation when relevant.
REVIEW
Check old scans before calling chronic infarct acute.
Review posterior fossa carefully because CT beam-hardening can hide early change.
Look for mimic signs: seizure change, tumor, venous thrombosis or hypoglycemia pattern.
RADIOLOGICAL IMAGING
Non-contrast CT brain.
CTA head and neck.
CT perfusion or MRI DWI/ADC/FLAIR when available.
ILLUSTRATIONS AND IMAGING
- Vascular territory map.
- ASPECTS checklist.
- Core versus penumbra diagram.