Effects of ＂Prominent laterality of the posterior cerebral artery＂ found on magnetic resonance angiography on the size and distribution of cerebral infarction and NIHSS scores during occlusion of the M1 segment of the middle cerebral artery

Abstract

Objective To investigate the relationship between the ＂prominent laterality of the posterior cerebral artery （PLPCA）＂ found on magnetic resonance angiography （MCA） and the size and distribution of cerebral infarction and the National Institutes of Health Stroke Scale （NIHSS）scores in patients with occlusion of the M1 segment of the middle cerebral artery （MCA）.Methods Fifty patients with acute cerebral infarction caused by the occlusion of the M1 segment of MCA were divided into PLPCA positive group （n =24） and PLPCA negative group （n =26） according to MRA manifestation.the NIHSS scores,size of cerebral infarction scores,and constituent ratios of distribution in all the feeding subregions of MCA in both groups were compared.Results The proportions of the patients with ≥3 risk factors （9/24 vs.18/26,P =0.046）,NIHSS scores （5.4 4.4 vs.10.4 ±4.9,t = -3.690,P =0.001）,and the size of cerebral infarction scores （1.92 ± 1.10vs.2.88 ± 1.37,t = -3.690,P =0.001） in the PLPCA positive group were significantly lower than those in the PLPCA negative group.The proportions of the patients with cerebral infarction involying the middle branch of the MCA territory （6/24 vs.19/26,P =0.002） and the posterior branch of the MCA territory （2/24 vs.5/26,P 〈0.001） in the PLPCA positive group were significantly lower than those in the PLPCA negative group.The proportions of the patients whose infarction involving the area of the posterior watershed zone were significantly higher than those in the PLPCA negative group （6/24 vs.1/26,P =0.045）,and the proportions of complete infarction were significantly lower than those in the PLPCA negative group （0/24 vs.6/26,P =0.023）.Conclusions When MCA M1segment was occluded,if PLPCA were observed on MRA,it indicated that the infarct size was smaller and the NIHSS score was lower.The infarction was less involved in the middle and post branches of MCA,and it is prone to have posterior watershed infarction. Key words: Infarction,middle cerebral artery; Magnetic resonance angiography; Posterior cerebral artery; Cerebrovascular circulation; Collateral circulation