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Cerebral hemispheric low-flow infarcts in arterial occlusive disease. Lesion patterns and angiomorphological
1Department of Neuroradiology, University Hospital of the Technical University (RWTH), Aachen, Germany.
Insights
Subcortical infarcts often result from low-flow conditions. A compromised Circle of Willis, identified via angiography, is a key predisposing factor for these brain infarcts.
Area of Science:
- Neurology
- Vascular Neurology
- Neuroimaging
Background:
- Subcortical infarcts stem from small-vessel disease, artery occlusions, or hemodynamic compromise.
- Topographic classification of infarcts using CT and MRI can be unreliable.
Purpose of the Study:
- To investigate the pathogenetic causes of subcortical hemispheric infarcts.
- To correlate imaging findings with vascular compromise in low-flow infarcts.
Main Methods:
- Evaluated 30 patients with presumed supratentorial low-flow infarcts.
- Utilized CT (30 patients) and MRI (14 patients).
- Detailed angiography of extracranial and intracranial arterial systems.
Main Results:
- Typical CT/MRI patterns included multilocal chainlike or confluent striated lesions in deep white matter.
- Extracranial occlusive disease or middle cerebral artery stenosis was frequent.
- A noncompetent Circle of Willis was observed in 29 out of 30 patients.
Conclusions:
- Low-flow infarcts exhibit characteristic imaging patterns but are not pathognomonic.
- Definitive diagnosis necessitates understanding complex vascular compromise.
- A noncompetent Circle of Willis is a significant predisposing factor for hemispheric low-flow infarcts.
Background And Purpose:
Among the pathogenetic causes of subcortical hemispheric infarcts are small-vessel disease, thromboembolic occlusions of small arteries, and hemodynamic compromise in low-flow conditions. A topographic classification of these infarcts based on CT and MRI can be misleading.
Methods:
We evaluated 30 consecutive patients with presumed supratentorial low-flow infarcts. CT was available in all cases, with additional MRI in 14 patients. In all cases the occlusion pattern of the extracranial and intracranial arterial system was studied in detail with angiography.
Results:
The dominant lesion patterns seen on CT and MRI were multilocal chainlike lesions in 19 and confluent striated lesions in 8 cases located in the supraventricular and paraventricular deep white matter. In 8 patients subcortical lesions extended into the adjacent cortex. Angiography revealed that extracranial occlusive disease (n = 24) or stenosis of the middle cerebral artery (n = 6) was always accompanied by impairment of the circle of Willis, in either the anterior part (n = 25) and/or the posterior part (n = 16). Moreover, leptomeningeal pathways indicative of vascular hemispheric compromise were identified in 26 cases. In total, 29 of 30 patients displayed a noncompetent circle of Willis.
Conclusions:
Low-flow infarcts show typical but not pathognomonic lesion patterns on CT and MRI. Definite diagnosis requires knowledge of the complex vascular compromise of the extracranial and/or intracranial arterial system. A noncompetent circle of Willis should be regarded as the additional predisposing condition in hemispheric low-flow infarcts.