In vivo flow territory mapping of major brain feeding arteries.
ABSTRACT The ability to visualize the perfusion territories of major feeding arteries to the brain is important for many clinical applications. Since the work of Duret in 1874 on vascularization of the brain, many textbooks and atlases have shown schematic drawings of the supply areas of the major cerebral arteries. Recent postmortem studies demonstrated that the variability of the cerebral vascular territories is significantly greater than previously assumed. The aim of the present study was to investigate in vivo, the variability of flow territories of major brain feeding arteries. Flow territory mapping of the anterior (internal carotid arteries) and posterior (basilar artery) circulation was performed in 115 (58 +/- 9 years of age) subjects with selective arterial spin labeling MRI. Flow territory maps for the entire population indicated significant variation in flow territories. However, when the subjects are further categorized into groups with a complete circle of Willis, with a missing A1 segment and with a unilateral or bilateral fetal-type posterior cerebral artery, the results showed considerably lower variation within groups. It is therefore concluded that, the variation observed from the entire population is mainly caused by anatomical variants of the circle of Willis. To relate focal brain lesions to underlying flow territories in individual cases, knowledge of the anatomy of the circle of Willis is essential.
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ABSTRACT: We have previously reported that the topographic variability of the territories of the anterior, middle, and posterior cerebral arteries is much larger than is generally considered in the literature. In the current study, we quantitatively investigated the variability of the territorial distribution of the major cerebral arteries and analyzed its relation to the variability of the circle of Willis. In 23 human brains, the volumes of the major cerebral territories were calculated and the diameters of the contributing arteries were measured and standardized for size. The variability of the standardized territorial volumes proved to be considerably large and strongly correlated with the variability of the diameters of the arteries emanating from the circle of Willis. Furthermore, the relative vascular densities in the gray and white matter were determined. Taking these densities into account, an estimation of the relative peripheral resistance of the contributing arteries was made. We hypothesize that the morphological variability of the cerebral vascular system is related to the peripheral resistance of the major cerebral arteries and, consequently, to flow patterns, both of which are hemodynamic factors. We suggest that hemodynamic factors predominantly determine the form and size of the cerebral vascular system.Stroke 01/1994; 24(12):1951-9. · 6.16 Impact Factor
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ABSTRACT: This paper presents schematic displays of the cerebral territories supplied by branches of the posterior artery as they would appear on axial and coronal computed tomographic (CT) scan sections. Companion diagrams of regional cortical function and a discussion of the fiber tracts are provided to simplify correlation of clinical deficits with coronal and axial CT abnormalities. Illustrations of the vascular supply and functional relay points (nuclei) of the thalamus are provided.American Journal of Roentgenology 08/1981; 137(1):13-9. · 2.90 Impact Factor
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ABSTRACT: After the occlusion of an internal carotid artery the principal source of collateral flow is through the arteries of the circle of Willis, but the size and patency of these arteries are quite variable. Study of the anatomy of the collateral pathways in patients with internal-carotid-artery occlusion with or without infarction in the watershed area of the deep white matter may identify patterns that afford protection from ischemic infarction. Using conventional magnetic resonance imaging and three-dimensional phase-contrast magnetic resonance angiography, we evaluated 29 consecutive patients (32 hemispheres at risk) with angiographically proved occlusion of the internal carotid artery. Four collateral pathways to the occluded vessel were evaluated: the proximal segment of the anterior cerebral artery, the posterior communicating artery, the ophthalmic artery, and leptomeningeal collateral vessels from the posterior cerebral artery. Only features of the ipsilateral posterior communicating artery were related to the risk of watershed infarction. The presence of posterior communicating arteries measuring at least 1 mm in diameter was associated with the absence of watershed infarction (13 hemispheres, no infarcts; P < 0.001). Conversely, there were 4 watershed infarcts in the 6 hemispheres with posterior communicating arteries measuring less than 1 mm in diameter and 10 infarcts in the 13 hemispheres with no detectable flow in the ipsilateral posterior communicating artery. A small (< 1 mm in diameter) or absent ipsilateral posterior communicating artery is a risk factor for ischemic cerebral infarction in patients with internal-carotid-artery occlusion.New England Journal of Medicine 07/1994; 330(22):1565-70. · 51.66 Impact Factor