Artery anterior cerebral

WM lesions are rated separately in four WM areas periventricular, deep, watershed, and subcortical WM. By definition, periventricular WM foci have to be in contact with the ventricular wall, deep WM foci separated from the ventricles by a strip of normal-appearing WM and located outside watershed regions. Watershed regions are the areas located between the territories of two of the main cerebral arteries, like middle cerebral artery and anterior cerebral artery or middle cerebral artery and posterior cerebral artery. The subcortical... 

These include infarcts in the territory of (1) the deep perforators of the MCA, anterior cerebral artery (ACA) and posterior cerebral artery (PCA), posterior communicating artery (PcomA), the lenticulo-striate arteries and the anterior choroidal artery (2) the superficial perforators (white matter medullary branches) of the superficial pial arteries (3) border-zone or junctional infarcts between 1 and 2 (4) combined infarcts. Small (< 1.5 mm infarcts - lacunes) are usually caused by single perforator disease while larger infarcts have a more diverse pathophysiology including embolism and MCA stenosis (Bang et al. 2002). 

Fig. 14.3. Bilateral (acute and non-recent) anterior cerebral artery infarcts causing paraparesis...

Wolff V, Saint Maurice JP, Ducros A et al (2002) Akinetic mutism and anterior bicerebral infarction due to abnormal distribution of the anterior cerebral artery. Rev Neurol (Paris) 158 377-380... 

The internal carotid artery starts as the carotid sinus at the bifurcation of the common carotid artery at the level of the thyroid cartilage. It runs up the neck, without any branches, to the base of the skull where it passes through the foramen lacerum to enter the carotid canal of the petrous bone. It then runs through the cavernous sinus in an S-shaped curve (the carotid siphon) pierces the dura and exits just medial to the anterior clinoid process. It then bifurcates into the anterior cerebral artery and the larger middle cerebral artery. 

Fig. 4.1. The anatomy of the arterial circulation to the brain and eye. Gray indentations into the arterial lumen represent sites at which atherothrombosis is particularly common. ACA, anterior cerebral artery EGA, external carotid artery ICA, internal carotid artery MCA, middle cerebral artery PCA, posterior cerebral artery.

The anterior cerebral artery passes horizontally and medially to enter the interhemi-spheric fissure it then anastomoses with its counterpart of the opposite side via the anterior communicating artery, curves up around the genu of the corpus callosum and supplies the anterior and medial parts of the cerebral hemisphere. Small branches also supply parts of the optic nerve and chiasm, hypothalamus, anterior basal ganglia and internal capsule. 

The circle of Willis. This is formed by the proximal part of the two anterior cerebral arteries connected by the anterior communicating artery, and the proximal part of the two posterior cerebral arteries, which are connected to the distal internal carotid arteries by the posterior communicating arteries. However, approximately 50% of circles have one or more hypoplastic or absent segments, usually one of the communicating arteries, and atheroma may limit the potential for collateral flow (Fig. 4.2). 

Around the orbit. Branches of the external carotid artery can anastomose with branches of the ophthalmic artery if the internal carotid artery is severely stenosed or obstructed. Collateral flow from the external carotid artery into the orbit then passes retrogradely through the ophthalmic artery to fill the carotid siphon, middle cerebral artery and anterior cerebral artery. Sometimes flow may even reach the posterior cerebral artery and vertebrobasilar system. 

Partial anterior circulation infarcts (Fig. 9.4) are caused by occlusion of a branch of the middle cerebral artery, or rarely the trunk of the anterior cerebral artery. They are usually... 

Borggreve F, de Deyn PP, Marien P etal. (1994). Bilateral infarction in the anterior cerebral artery vascular territory due to an unusual anomaly of the circle of Willis. Stroke 25 1279-1281... 

Kazui S, SawadaT, NaritomiH etal. (1992). Left unilateral ideomotor apraxia in ischaemic stroke within the territory of the anterior cerebral artery. Cerebrovascular Diseases 2 35-39... 

Fig. 2.3 (a) Internal carotid artery feeds the middle cerebral artery (MCA) and anterior cerebral artery (ACA). (b) Right internal cerebral artery (ICA). Adapted from Fisher [93]... 

Fig. 4.1 Overlapping thick slab MlPs. A sequential set of 6 images from a series of 26 thick slab (30 mm), MIP reconstructions that overlap at 5 mm intervals, in these six images the entire courses of the middle cerebral artery Ml, M2, and more distal branches are well visualized. The bilateral anterior cerebral artery Al segments are also well delineated. The thick slab...

Fig. 6.16 Anterior cerebral artery occlusion and infarct. MIP of 3D TOP MRA (a) shows absent flow-related enhancement of the distal A2 segment of the left ACA arrow in a). This corre-...

The pial collateral circulation to the MCA territory, primarily from the anterior cerebral artery and to a lesser degree from the posterior cerebral artery, is the main determinant of the degree of CBF impairment, and thus the rate of neuronal loss [40], The strength of the collateral circulation is variable between patients and has been shown to be a significant predictor of clinical outcome and tissue fate [35, 105-107], The presence of a substantial ischemic penumbra (hypoperfused but viable tissue) is a marker of good collaterals, represents a therapeutic target that is tailored to each patient s individual physiology, and supersedes time as the more important parameter for the decision to proceed with lAT. 

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