The Study The Realtionship Between Vertebral Artery Stenosis Or Obstruction And Posterior Cerebral Ischemia

By applying the64-slice spiral CT angiography (CTA) and magnetic resonance imaging (MRI), analysing the location and degree of the vertebral artery stenosis and obstruction, and the character of the posterior cerebral ischemic lesions to study the pathogenesis of the posterior cerebral infarction that caused by vertebral artery stenosis and obstruction.Materials and Methods:Our study retrospectively analyzes the CTA and MRI results of101posterior cerebral ischemic patients with vertebral artery stenosis and obstruction from August2011to April2012. Observing the vertebral dominance, comparing the incidence and the extent of the stenosis of the donimant vertebral artery and non donimant vertebral artery. The incidence and the extent of the stenosis of different segments of vertebral artery are also conpared. Comparing the locations of posterior cerebral infarction of different segments of vertebral artery and the volumed of posterior cerebral infarction of different degree of the stenosis of vertebral artery. According to whether accompanied with the internal carotid artery stenosis or not, all the cases are divided into two groups, group A:accompanied with the internal carotid artery stenosis; group B:not accompanied with the internal carotid artery stenosis, then compare the types and characters of the cerebral infarction.Results:①Cases of this group mostly have left vertebral artery dominance (accounted for48.51%of the total), and the incidence of the stenosis or obstruct of the non donimant vertebral artery is much higher than that of donimant vertebral artery.(100、69.00%); and for most cases the degree of the stenosis of vertebral artery is moderate or severe (respectively33.33%,24.00%and42.22%,43.00%), but there is no significant difference of the extent of the stenosis between the two groups(P>0.05);②vertebral artery stenosis is more common in the initial segment of vertebral artery (107,54.31%); vertebral artery occlusion occurs mainly in the intracranial segment of vertebral artery, account for63.16%;③Vertebral artery stenosis or obstruction mostly associates with carotid artery stenosis (68,67.33%), the infarctions of the group associated with carotid artery stenosis is mainly locate at frontal lobe、parietal lobe、occipital lobe、temporal lobe、Basal ganglia、semioval center and paraventricular brain tissue, while infarctions of the group not associated with carotid artery stenosis is mainly located in thalamus、cerebellum and pons, there is no significant difference between the two groups (P<0.05); the difference between the incidences of large area cerebral infarction-group and lacunar infarction-group o isn’t significant (P>0.05); the difference between the incidences of single cerebral infarction and multiple cerebral infarction of the two groups isn’t significant (P>0.05),Both the groups are maimly have multiple cerebral infarctions, respectively72.06%and57.58%.④The difference of the locations of cerebral infarction of different segments of vertebral stenosis isn’t significant (P>0.05); The difference of the volume of cerebral infarction of different degrees of vertebral artery stenosis is significant (P<0.05).With the deterioration of degree of vertebral artery stenosis, the volume of cerebral infarction is getting larger, and the volume of cerebral infarction of bilateral vertebral artery stenosis or obstruction is significantly larger than that of single vertebral artery stenosis or obstruction.Conclusion:The non donimant vertebral artery are much easier prone to vertebral artery stenosis or obstruction.Stenosis of vertebral artery is more common in the initial segment, while obstruction of vertebral artery occurs mainly in the intracranial segment. Stenosis of vertebral artery which is above moderate is the main reason of posterior cerebral ischemia. Vertebral artery stenosis or obstruction are mostly associated with carotid artery stenosis and multiple infarctions are usually seen.Different locations of stenosis of vertebral artery are independence with the locations of brain ischemia.Significent deviation can be seen in the volumes of ischemic infarction due to different degrees of vertebral artery stenosis. As the degree of stenosis getting severe, the volume of the infarction gets larger. The volume of infarction caused by bilateral stenosis of vertebral artery is obviously larger than that of single vertebral artery stenosis or obstruction.