Cause Analysis Of Blood Flow Velocity Slowed Down In Vertebral Artery By Transcranial Doppler Ultrasound Examination

Objective:To explore causes of blood flow velocity slowed down in vertebral artery and the relationship between blood flow spectrum form in vertebral artery and morphological changes of posterior circulation artery by analyzing morphological characterristies of vertebral artery blood flow spectrum and posterior circulation artery for improving the significance of transcranial doppler ultrasound in etiological diagnosis of vertebral artery blood flow velocity slowed down.Methods:87 patients with vertebral artery mean blood flow velocity slowed down by transcranial doppler ultrasound examination were selected from January 2010 to August 2010 and were grouped intoⅠ,Ⅱ,Ⅲtype by the blood flow spectrum form. Head magnetic resonance angiography(MRA) and neck computertomograpphy angiography (CTA) were done for all patiens in two weeks after ranscranial doppler ultrasound examination. The results of MRA, CTA and TCD in all patients were comparatively analyzed.Results:(1) In 87 patients,134 vertebral arteries with mean blood flow velocity slowed down were detected. According to the blood flow spectrum form groups,85 vertebral arteries with I type,36 vertebral arteries withⅡtype and 13 vertebral arteries with III type were detected. (2) In normal group and slow group of vertebral artery mean blood flow velocity, the rates of posterior circulation vascular abnormalities were respectively 40.00%and 64.93%, the latter was significantly higher than the former (X2=7.92, P<0.01). (3) In I, II and III type of vertebral artery blood flow spectrum form, the rates of posterior circulation vascular abnormality were respectively 58.82%,66.67% and 100.00%. Compared to I type and II type, there was more higher rate of posterior circulation vascular abnormality in III type (X2, respectively 6.62 and 4.09, P<0.05). (4) Compared to normal group of posterior circulation vascular morphology, vertebral arteries of I type blood flow spectrum form were significantly fewer and vertebral arteries of II type blood flow spectrum form were significantly more in vertebral artery developmental variation goup (X2=4.04, P<0.05); vertebral arteries of I type blood flow spectrum form were significantly fewer (X2=5.51, P<0.05), vertebral arteries of III type blood flow spectrum form were significantly more (P=0.000) in extracranial vertebral artery stenosis or occlusion goup. (5) In 87 patients, the patients in male were significantly more than those in female (μ=7.12, P<0.01); the cases in less than or equal to 60 years old were significantly fewer than those in more than 60 years old (μ=3.79, P<0.01).Conclusion:Patients with blood flow velocity slowed down in vertebral artery had mostly morphology abnormality in posterior circulation vascular. Blood flow spectrum forms in vertebral artery were closely correlated to posterior circulation vascular morphology changes. Characteristic changes in vertebral artery blood flow spectrum forms contributed to the diagnosis of posterior circulation vascular morphology abnormalities.