Clinico-radiological study of collateral circulation after internal carotid and middle cerebral occlusion

Area of Science:

• Neurology
• Vascular Neurology
• Neuroimaging

Background:

• Internal carotid artery (ICA) and middle cerebral artery (MCA) occlusions are significant causes of ischemic stroke.
• The circle of Willis (CoW) is a primary source of intracranial collateral circulation.
• The role of non-CoW collateral pathways in stroke pathophysiology remains an area of active investigation.

Purpose of the Study:

• To investigate the presence and significance of intracranial collateral channels, beyond the circle of Willis, in patients with ICA and MCA occlusion.
• To determine the relationship between the development of these collaterals and the speed of stroke onset.
• To evaluate the protective role of these collaterals in different arterial occlusion scenarios.

Main Methods:

• Angiographic study of 34 patients with internal carotid artery occlusion.
• Angiographic study of 19 patients with middle cerebral artery occlusion.
• Assessment of collateral channel presence and comparison with stroke development time and location.

Main Results:

• Intracranial collaterals (apart from the CoW) were found in a high percentage of patients within one week of stroke onset.
• These collaterals were more frequently observed in cases where the stroke developed slowly.
• In MCA occlusion, the presence of these collaterals appeared to offer some protection against infarction.
• In ICA occlusion, these collaterals were less critical than the CoW, and their presence suggested CoW inadequacy.

Conclusions:

• Non-circle of Willis intracranial collateral channels are frequently present after stroke, particularly in slow-onset cases.
• These collaterals play a potentially protective role in MCA occlusions.
• Their significance in ICA occlusions is secondary to the CoW, and their presence may indicate a compromised CoW.