The clinical significance of evaluating collateral circulation in patients with chronic middle cerebral artery occlusion by ultrasound

Objective To study the clinical significance of transcranial Doppler (TCD) and/or transcranial color-coded sonography (TCCS) in the evaluation of collateral circulation in patients with unilateral chronic middle cerebral artery occlusion (CMCAO). Methods From August 2015 to April 2018, 54 consecutive patients diagnosed as unilateral CMCAO by TCD and/or TCCS and confirmed by digital subtraction angiography (DSA) from the First Affiliated Hospital of Soochow University were enrolled retrospectively. The leptomeningeal anastomoses (LMA) grades on DSA were recorded. TCD and/or TCCS were used to measure and record the mean velocity (MV) of bilateral anterior cerebral artery (ACA) and posterior cerebral artery (PCA), and the ratios of ipsilateral MV to the contralateral were calculated (MViACA/MVcACA, MViPCA/MVcPCA). Spearman rank correlation analysis was used to analyze the correlation between ACA, PCA blood flow parameters and LMA grades on DSA. All patients were divided into three groups according to clinical symptoms: asymtom group (n=8) and transient ischemic attack (TIA) group (n=19)and cerebral infarction (CI) group (n=27). The differences in ACA and PCA blood flow parameters and relative CT perfusion parameters were compared between the three groups. Results MViACA and MViACA/MVcACA were significantly positively correlated (r=0.568, P=0.000; r=0.757, P=0.000); MViPCA and MViPCA/MVcPCA were positively correlated with LMA grades on DSA (r=0.383, P=0.004; r=0.624, P=0.000). MViACA, MViPCA and MViACA/MVcACA, MViPCA/MVcPCA in asymtom group and TIA group were higher than those in CI group, and the differences were statistically significant (P<0.05). Relative cerebral blood flow (rCBF) and relative cerebral blood volume (rCBV) in asymtom group and TIA group were higher than those in CI group, and the differences were statistically significant (P<0.05), the relative mean transit time (rMTT) and relative peak time (rTTP) were lower in asymtom and TIA group than in CI group, and the differences were statistically significant (P<0.05). Conclusion The hemodynamic parameters of ACA and PCA on TCD and/or TCCS have significant correlation with the LMA grades on DSA and have good consistency with the CTP results, which play an important role in guiding patients with unilateral CMCAO to select individualized treatment strategies. Key words: Ultrasonography, Doppler, transcranial; Infarction, middle cerebral artery; Collateral circulation