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MRA flow quantification in patients with a symptomatic internal carotid artery occlusion. The Dutch EC-IC Bypass
K J van Everdingen1, C J Klijn, L J Kappelle
1Department of Radiology, University Hospital Utrecht, Netherlands.
Insights
In internal carotid artery (ICA) occlusions, the contralateral ICA compensates for reduced flow. Cerebropetal blood flow decreases significantly only with bilateral ICA occlusions, highlighting the importance of an open contralateral artery.
Area of Science:
- Neurology
- Vascular Imaging
- Cerebrovascular Disease
Background:
- Internal carotid artery (ICA) occlusions pose a risk for future stroke.
- Assessing collateral circulation is crucial for stroke risk stratification.
- Magnetic resonance angiography (MRA) enables quantitative flow assessment in cerebral vessels.
Purpose of the Study:
- To quantitatively measure cerebropetal blood flow in patients with ICA occlusions.
- To evaluate the role of collateral arteries in maintaining cerebral perfusion.
- To correlate flow dynamics with the degree of ICA stenosis.
Main Methods:
- Fifty-four patients with ICA occlusion and 16 controls underwent 2D phase-contrast MRA.
- Quantitative flow measurements were performed in major cerebral arteries (ICA, MCA, basilar artery, common carotid arteries).
- Flow data were analyzed based on unilateral/bilateral ICA occlusion and contralateral ICA stenosis.
Main Results:
- Unilateral ICA occlusion with contralateral stenosis led to increased flow in the contralateral ICA and basilar artery.
- Bilateral ICA occlusions resulted in increased basilar artery flow but decreased total cerebropetal flow.
- Flow was significantly reduced in the ipsilateral and contralateral middle cerebral arteries (MCA) in all patient groups.
Conclusions:
- The contralateral internal carotid artery (ICA) is the primary collateral pathway in unilateral ICA occlusion.
- Total cerebropetal blood flow is maintained unless both ICAs are occluded.
- An open contralateral ICA is vital for preserving normal cerebral blood flow in symptomatic ICA occlusions.
Background And Purpose:
Flow measurements in the collateral arteries of patients with internal carotid artery (ICA) occlusions may be important to estimate the risk of future stroke. Quantitative flow measurements in cerebropetal vessels can be reliably assessed by means of magnetic resonance angiography (MRA).
Methods:
Fifty-four patients with transient or minor ischemic neurological deficits and an angiographically proven ICA occlusion and 16 control subjects underwent two-dimensional phase-contrast MRA quantitative flow measurements through the common carotid arteries, basilar artery, ICAs, and middle cerebral arteries (MCA).
Results:
Patients with a unilateral ICA occlusion and a 0% to 69% stenosis of the contralateral ICA had increased flow in the contralateral ICA (P < .005) and in the basilar artery (P < .005) compared with control subjects. Even patients with a 70% to 99% stenosis contralateral to the ICA occlusion had increased flow in the ICA (P < .05) as well as increased flow in the basilar artery (P < .001). Total cerebropetal flow was not significantly different between these patients and control subjects. Patients with bilateral ICA occlusions had an increased flow in the basilar artery (P < .001), while the total cerebropetal flow was less than in control subjects (P < .001). In all patients, flow was decreased in the ipsilateral MCA (P < .001) and in the contralateral MCA (P < .05).
Conclusions:
The contralateral ICA is the main supplying artery in patients with an ICA occlusion. Total cerebropetal flow decreases only when both ICAs are occluded. In patients with symptomatic ICA occlusions, an open contralateral ICA is probably important to retain the cerebral blood flow within normal limits.