Moyamoya disease: a summary.

Moyamoya, meaning a "hazy puff of smoke" in Japanese, is a chronic, occlusive cerebrovascular disease involving bilateral stenosis or occlusion of the terminal portion of the internal carotid arteries (ICAs) and/or the proximal portions of the anterior cerebral arteries and middle cerebral arteries (MCAs). The Ministry of Health and Welfare of Japan has defined 4 types of moyamoya disease (MMD): ischemic, hemorrhagic, epileptic, and "other." The ischemic type has been shown to predominate in childhood, while the hemorrhagic type is more often observed in the adult population. The highest prevalence of MMD is found in Japan, with a higher female to male ratio. Studies have shown a possible genetic association of MMD linked to chromosome 17 in Japanese cases as well as in cases found in other demographics. During autopsy, intracerebral hematoma is found and most commonly serves as the major cause of death in patients with MMD. Moyamoya vessels at the base of the brain are composed of medium-sized or small muscular arteries emanating from the circle of Willis, mainly the intracranial portions of ICAs, anterior choroidal arteries, and posterior cerebral arteries, forming complex channels that connect with distal positions of the MCAs. Off of these channels are small tortuous and dilated vessels that penetrate into the base of the brain at the site of the thalamoperforate and lenticulostriate arteries. On angiography, there is the characteristic stenosis or occlusion bilaterally at the terminal portion of the ICAs as well as the moyamoya vessels at the base of the brain. Six angiographic stages have been described, from Stage 1, which reveals a narrowing of the carotid forks, to Stage 6, in which the moyamoya vessels disappear and collateral circulation is produced solely from the external carotid arteries. Cases with milder symptoms are usually treated conservatively; however, more severe symptomatic cases are treated using revascularization procedures. Surgical treatments are divided into 3 types: direct, indirect, and combined/other methods. Direct bypass includes superficial temporal artery-MCA bypass or use of other graft types. Indirect procedures bring in circulation to the intracranial regions by introducing newly developed vasculature from newly approximated tissues. These procedures may not be enough to prevent further ischemia; therefore, a combination of direct and indirect procedures is more suitable. This article will give a review of the epidemiology, natural history, pathology, pathophysiology, and diagnostic criteria, including imaging, and briefly describe the surgical treatment of MMD.

Association of an irregularly shaped anterior choroidal aneurysm with CREST syndrome. Case report.

The authors present the case of a 50-year-old woman with a history of CREST syndrome (calcinosis, Raynaud phenomenon, esophageal motility disorders, sclerodactyly, and telangiectasia), a variant of scleroderma, who was incidentally found to have an irregular intracranial aneurysm. The patient presented with migraine headaches. A magnetic resonance image of the brain obtained during the headache workup revealed a right posterior carotid artery wall aneurysm in the region of the anterior choroidal artery (AChA). On digital subtraction angiograms, the lesion measured 3.5 mm at its largest diameter. Because of the irregular shape of the aneurysm, the patient's relatively young age, and the potential for further aneurysm growth due to collagen disease, surgical clip application was recommended following a discussion of available treatment options. At surgery, the aneurysm was identified as bilobed and broad based, and the AChA was found to be associated with the aneurysm neck. Satisfactory clipping of the aneurysm was achieved with preservation of the parent vessels. An association of CREST syndrome with intracranial aneurysms has only been reported once before. This case is presented to draw attention to the possibility of a pathophysiological connection between CREST syndrome and intracranial aneurysms and to postulate a possible mechanism whereby this condition may result in aneurysm formation. The association of aneurysms with other pathological collagen-related conditions is well known, and literature relevant to a possible connection between CREST syndrome and aneurysms is reviewed and discussed.