Cerebral arteries

Basic aspects of the proteins of the blood coagulation system and of fibrinolysis are described in this chapter. Some fundamental aspects of platelet biology are also presented. Hemorrhagic and thrombotic states can cause serious medical emergencies, and thromboses in the coronary and cerebral arteries are major causes of death in many parts of the world. Rational management of these conditions requires a clear understanding of the bases of blood clotting and fibrinolysis. 

Occasionally, the diagnosis of acute ischemia can be established by NCCT because embohc material can be visualized directly, usually in the MCA or its branches. Emboli are often more radiodense than normal brain tissue, and therefore an affected proximal MCA may appear as a linear hyperdensity ( hyperdense middle cerebral artery sign or HMCA sign, Fig. 2.1c). One study found that the HMCA sign was 100% specific for MCA occlusion, but only 27% sensitive, probably because the density of embohc material is often indistinguishable from that of the normal MCA. ... 

With modern multislice scanners and optimized protocols," CTA images can provide excellent visualization of the primary intracranial arteries (i.e., the proximal anterior, middle, and posterior cerebral arteries), their smaller secondary... 

FIGURE 2.6 Dynamic susceptibility contrast imaging. Axial images of the brain are acquired repeatedly, in this case every 1.5 seconds. As a bolus of intravenously injected contrast material enters the brain, first arteries, then brain parenchyma, and finally veins demonstrate a transient loss of signal intensity. In this acute stroke patient, hypoperfusion of the left middle cerebral artery territory results in delayed arrival of the contrast bolus and prolonged stasis of contrast within the tissue. 

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Slivka A, Murphy E, Horrocks L. Cerebral edema after temporary and permanent middle cerebral artery occlusion in the rat. Stroke 1995 26 1061-1065. 

Lev MH, Segal AZ, Farkas J, Hossain ST, Putman C, Hunter GJ, Budzik R, Harris GJ, Buonanno FS, Ezzeddine MA, Chang Y, Koroshetz WJ, Gonzalez RG, Schwamm LH. Utility of perfusion-weighted CT imaging in acute middle cerebral artery stroke treated with intra-arterial thrombolysis prediction of final infarct volume and clinical outcome. Stroke 2001 32 2021-2028. 

Endo H, Inoue T, Ogasawara K, Fukuda T, Kanbara Y, Qgawa A. Quantitative assessment of cerebral hemodynamics using perfusion-weighted MRI in patients with major cerebral artery occlusive disease comparison with positron emission tomography. Stroke 2006 37 388-392. 

Based primarily on the study protocol of the 1995 NINDS rt-PA study.Many centers would also exclude patients with known documented endocarditis or aortic dissection, and those with CT hypoattenuation in more than one third of the middle cerebral artery territory. There are insufficient data to support the use of rt-PA for ischemic stroke in pregnancy or in the pediatric population (age <18 years). 

Middle Cerebral Artery Occlusion and the PROACT Trial The safety and efficacy of lAT in the anterior circulation have been evaluated in two randomized, multicenter, placebo-controlled trials. In the Prolyse in Acute Cerebral Thromboembolism (PROACT) 1 and 11 trials, patients with proximal MCA (Ml or M2 segment) occlusions within 6 hours of symptom onset were treated with recombinant prourokinase (r-pro-UK) or placebo. ... 

A significant neurologic deficit expected to result in long-term disability, and attributable to large vessel occlusion (basilar, vertebral, internal carotid, or middle cerebral artery M1 or M2 branches). 

Ueda T, Hatakeyama T, Kohno K, Kumon Y, Sakaki S. Endovascular treatment for acute thrombotic occlusion of the middle cerebral artery local intra-arterial thrombolysis combined with percutaneous transluminal angioplasty. Neuroradiology 1997 39 99-104. 

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Nakano S, Iseda T, Yoneyama T, Kawano H, Wakisaka S. Direct percutaneous transluminal angioplasty for acute middle cerebral artery trunk occlusion an alternative option to intra-arterial thrombolysis. Stroke 2002 33 2872-2876. 

Sauvageau E, Levy EL Self-expanding stent-assisted middle cerebral artery recanalization technical note. Neuroradiology 2006 48 405 08. 

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Corbett D, Hamilton M, Colboume F. Persistent neuroprotection with prolonged postischemic h3fpothermia in adult rats subjected to transient middle cerebral artery occlusion. Exp Neurol 2000 163 200-206. 

Schwab S, Schwarz S, Spranger M, Keller E, Bertram M, Hacke W. Moderate hypothermia in the treatment of patients with severe middle cerebral artery infarction. Stroke 1998 29 2461-2466. 

Weinstein PR, Anderson GG, Telles DA. Results of h3fperbaric oxygen therapy during temporary middle cerebral artery occlusion in unanesthetized cats. Neurosurgery 1987 20 518-524. 

EC-IC arterial bypass involves the use of general anesthesia, open craniotomy, and end-to-side anastomosis of the superficial temporal artery to a branch of the middle cerebral artery (MCA) (Fig. 6.1). Currently, this technique is being used primarily in the setting of intracranial aneurysm therapy, moyamoya disease, and... 

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