TCCS studies were analyzed mainly considering the Doppler waveform, because of the existing classification of the MCA flow patterns (see Appendix A), made to classify Tanespimycin nmr TCD findings [8]. All patients with bilateral involvement but one had the same flow pattern in the MC A on both sides and a similar situation was reported for the DSA classification [9] (see Appendix B) but not in the same patients. Both neurosonological and MRA findings

were unchanged in the follow up examinations and no patients reported focal neurological events of vascular origin during the follow-up. In Fig. 1 it is showed an example of the findings from the three techniques (TCCS, MRA, DSA) in two patients of our series. Bioactive Compound Library manufacturer For the reasons detailed in the introduction, there are few data about the natural

course of the moyamoya disease in asymptomatic patients, mainly in adult people, both in Asian and particularly in European population. The lack of reliable informations is even more evident for asymptomatic patients, particularly for the adult form of the disease, because the introduction of noninvasive diagnostic tools made possible the sporadical identification of asymptomatic subjects. In a Japanese questionnaire survey, made in 88 neurosurgical institutes in 1994, to define clinical features and outcome of asymptomatic moyamoya disease [10], only thirty three asymptomatic moyamoya disease patients were collected (11 male, 22 female) and divided into 2 groups: patients without any symptoms (group 1, mainly adult people), and patients without any symptoms except headache (group 2). In this survey the natural course of asymptomatic moyamoya disease seemed benign and the need of a dedicated prospective study about this item was proposed. But in the next years the non-invasive screening led to a change in the known epidemiological data, also in the Japanese population, as shown in a more recent all-inclusive survey of moyamoya disease in Hokkaido island (population 5.63 million) [11], that analyzed data from 267 newly registered Carbohydrate patients with moyamoya

disease from 2002 to 2006. Overall the prevalence of the disease and the age at onset were reported higher than those previously known. The highest peak of onset age was older than those reported previously. In addition, 17.8% of patients were asymptomatic at onset in all decades. In European population the moyamoya disease has also a lesser prevalence, therefore large epidemiological data are lacking, mainly about asymptomatic people. The limited existing European studies mostly deal with a mixed cohort of MMD and angiographic syndromes caused by other conditions, as in Khan’s study [12] about surgical revascularization (15 of 23 patients with moyamoya angiopathy had idiopathic moyamoya disease).