Comparison of cerebral Hemodynamics Between Symptomatic and Asymptomatic Cerebral Small Vessel Disease

Abstract

Objectives To investigate the changes of intracranial hemodynamics of symptomatic and asymptomatic in patients with the small vessel disease (SVD), to find the cut off value for the diagnosis of SVD by TCD. Methods Form June 2013 to December 2014, a total of 279 SVD patients were recruited confirmed by magnetic resonance imaging (MRI) in the Second Clinical Hospital of Guangzhou University of Traditional Chinese Medicine. All patients underwent magnetic resonance angiography (MRA), color Doppler ultrasound and TCD examination. The white matter lesions, number of infarcts and hemodynamic parameters were recorded. The cerebral vascular risk factors, stroke number, degree of cerebral white matter lesions and hemodynamic parameters were compared between symptomatic and asymptomatic in patients with SVD. The sensitivity and specificity of pulsatility index (PI) in the diagnosis of SVD were calculated, and the receiver operating characteristic (ROC) curve was plotted. Results There was statistically difference in degree of white matter lesion between the asymptomatic and symptomatic group (P<0.05). The degree of leukoaraiosis in asymptomatic SVD group was mainly grade 0~1 accounting for 34.6% (28/81) and 35.8% (29/81) respectively, and grade 3~4 accounting for 14.8% (12/81). In symptomatic SVD group, grade 0 accounted for 15.7% (31/198), grade 1~3 for 29.8% (59/198), 29.3% (58/198) and 25.3% (50/198), respectively. The proportion of leukoaraiosis with grade 0 in asymptomatic SVD was higher than in symptomatic group, while the grade 2~3 was lower than that in symptomatic SVD, and the difference was statistically significant (χ2=13.574, P=0.001; χ2=6.423, P=0.040; χ2=8.265; P=0.005). The mean flow velocity of vertebral artery (VA) and basilar artery (BA) in the symptomatic group was lower than that in asymptomatic group [(23.6±7.3) cm/s vs (27.8±7.0) cm/s, (31.9±10.3) cm/s vs (35.3±9.3) cm/s], and the difference was statistically significant (t=4.269, P<0.001; t=2.500, P=0.013). There was no significant difference in mean velocity of anterior cerebral artery (ACA), middle cerebral artery (MCA) and posterior cerebral artery (PCA) between the two groups. PI were higher in patients with symptom group than asymptomatic group (P<0.05). The mean flow velocity of vertebral and basilar artery of symptom group were lower than those in the asymptomatic group (P<0.05). The optimum cut-off values of PI in diagnosing symptomatic SVD were 1.05 and 1.10, and their sensitivity, specificity and area under the ROC curve was 37.9%, 78.7%, 0.590 and 22.6%, 82.5%, 0.534 respectively. Conclusion It may be lack of sensitivity to screen SVD by TCD, although the PI were higher in patients with the symptomatic SVD than the asymptomatic SVD. Key words: Ultrasonography, Doppler, transcranial; Small vessel disease; Hemodynamic