Initial Setting Of The Screening Criteria And Clinical Study Of Vertebrobasilar Dolichoectasia By Magnetic Resonance Imaging

Background Vertebrobasilar dolichoectasia (VBD) is a rare agnogenic disease with abnormalities involve posterior circulation vascular. The clinical manifestations verify largely in VBD, some patients even show no apparent clinical symptoms, which might lead to missed diagnosis or misdiagnosis. The initial diagnostic criteria of VBD was established by Smoker et al in 1986 , which depend on measurements of the diameter of the basilar artery (BA) on CT scan films using a graduated 20-diopter lens, which is relatively subjective. Magnetic resonance imaging (MRI) has now become a leading method in the diagnosis and screening of intracranial disease, however the screening criteria for VBD in adults by MRI in our country has not been reported yet. To our knowledge, this study is the first one to measure the diameter of VBA directly from the original images of MRI, thus make an initial screening criterion. This study also discuss risk factors of symptomatic VBD and the dependability between clinical manifestation and the different forms of VBA, thus provide a reference for diagnosis and early treatment for VBD .MethodsPart 1 All patients and healthy subjects in this study from the First Hospital of Jilin University from March 2010 to March 2011 were scanned by MRI and MRA. The original images were transferred to PACS database by digital imaging and communications in medicine(DICOM)form. Uniform rate of adjustment to the computer screen shows 400%. Mark the edges and measure the distance of target arteries on screen images by the mouse, with values accurate to 0.1mm, thus obtained their diameters.A total of 11 arteries were measured in each subjects:BA at midpons,V4 segment of vertebral artery (VA-V4) in both sides, P1 segment of posterior cerebral artery (PCA-P1) in both sides , C4 segment of internal carotid artery(ICA-C4) , M1 segment of middle cerebral artery (MCA-M1) , A1 segment of anterior cerebral artery (ACA-A1) . Statistical analysis and setting the criteria of MRI for VBD .Part 2 : according to the results of Part 1 , screening patients with suspected VBD and selected age-matched and sex-matched ones from healthy subjects . Collecting and compare its general information , risk factors for atherosclerosis and imaging and clinical features.Results:①The screening criteria of MRI for VBD : Ectasia , diameter of BA ,≥4.2mm in male ,≥4.1mm in female ; diameter of LVA≥3.8mm in male ,≥3.5mm in female ; diameter of RVA≥3.6mm in male ,≥3.2mm in female . Dolich ,VA combine to form basilar artery above the pontobulbar junction and ride across to opposite side . The height of the bifurcation and the transverse position of the BA≥2 level .②Clinical manifestation of VBD: posterior circulation ischemia is most common in 52 patients with VBD (40.4%) , especially the infarction in the territory of posterior cerebral artery(19.2%),18 cases (34.6%) with symptoms of cranial nerves and the brainstem compression stimulation , to most common is vertigo 15 cases (83.3%) , then of tinnitus , peripheral facial paralysis and facial spasm , bucking , trigeminal neuralgia , nystagmus or eye movement disorders.③Asymptomatic VBD is not uncommon(23 cases , 44%). For symptomatic group , average diameter of VBA , incidence of hypertension , with more than 2 AS risk factors , the rate of brainstem oppression or vertebral artery ride across signe , are all higher than asymptomatic group , the differences are significant.④According to the different forms of VBA divided VBD into three groups , the simple ectasia group , the simple dolich group and the dolichoectasia group , clinical manifestations are no significant differences between the groups.Conclusion:①The measured value of VBA on screen image of MRI can be regard as the screening criteria of MRI for VBD.②The diameter of VBA , brainstem compression signe , VA ride across signe , hypertensive and have more than two atherosclerosis risk factors are the risk factors for symptomatic VBD.③There is no specific dependablity between the different forms of VBA and clinical manifestation of VBD.