Flow Diversion on TCD in Symptomatic MCA Steno-Occlusive Disorder: Evidence of Leptomeningeal Collateral Circulation

ABSTRACT

BACKGROUND: To investigate the clinical significance of flow diversion (FD) of the anterior cerebral artery (ACA) or posterior cerebral artery (PCA), a transcranial doppler (TCD) was used in patients with middle cerebral artery (MCA) occlusive disorders. METHODS: This is a retrospective study of 51 patients from 1999 to 2001. FD was determined using TCD. Leptomeningeal collateral channels (LMCs) were identified by conventional angiography. The author analyzed the sensitivity, specificity, positive and negative predictability of FD of ACA or PCA to predict the LMCs, and also evaluated the relationship between FD and leptomeningeal collateral circulation. RESULTS: LMC was noted in 41% of patients with M1 (MCA) occlusive disorders. It showed a tendency of increasing prevalence with an increasing degree of M1 MCA stenosis (rho=0.605, p<0.001). FD was noted in 47% of patients with MCA occlusive diseases. It also had a tendency of high prevalence with an increasing degree of M1 MCA stenosis (rho=0.382, p=0.006). To predict the presence of LMCs, FD of ACA or PCA had a sensitivity of 81%, specificity of 76%, positive predictive value of 71% and negative predictive value of 85%. FD of ACA or PCA had a good correlation with LMCs in patients with MCA occlusive disorders (rho=0.568, p<0.001). CONCLUSIONS: These results suggest that FD had good sensitivity and specificity to predict the LMCs, and demonstrated that FD was a reliable source of evidence of LMCs in patients with M1 MCA occlusive disorders. Patients with M1 MCA stenosis had heterogeneous hemodynamics in the development of collateral circulation.