Vascular territories in stroke
Clinical signs of stroke follow arterial perfusion territories. Rapid bedside localisation (ACA, MCA, PCA, posterior circulation) guides urgent imaging and informs reperfusion or neurosurgical decisions. Use validated screening tools (FAST or ROSIER) and obtain prompt brain imaging (non‑contrast CT ± CTA; MRI DWI when available and likely to change management) (NICE NG128).
Typical clinical syndromes by major cerebral artery
Key screening and imaging points
- Use FAST or ROSIER for rapid recognition and establish time last seen well (NICE NG128).
- Initial imaging: non‑contrast CT head to exclude haemorrhage and identify early infarct changes.
- Perform CTA when large‑vessel occlusion (LVO) is suspected (NICE NG128; HTG403).
- MRI with diffusion‑weighted imaging (DWI) is more sensitive for early ischaemia and should be used when it will change management or clarify territory (NICE NG128).
Anatomical correlation - why patterns differ
- Somatotopic cortical representation explains common patterns: ACA supplies medial frontal/parietal regions (leg‑predominant weakness).
- MCA supplies lateral convexity including face/hand/arm and language cortex (face/arm‑predominant weakness, aphasia, neglect).
- PCA supplies occipital cortex and visual radiations (visual field defects) and thalamic branches (sensory syndromes).
- Proximal large‑vessel occlusions (e.g. ICA terminus, proximal MCA M1, basilar artery) produce more extensive cortical/subcortical infarction, greater deficit severity, and higher risk of malignant oedema-these patients are most likely to need thrombectomy or decompressive surgery.