| Part 1 Study on Classification of Vertebrobasilar Artery Geometry and the Influence of different Vascular Geometries on Basilar Artey Plaque Initiation Based on HR-MRIObjective:To investigate the geometry classification of vertebrobasilar artery and basilar artery plaque incidence in different vascular geometries.Material and Method:Three hundred and three consecutive patients with ischemic stroke or transient ischemic attack in posterior circulation underwent high-resolution magnetic resonance imaging(HR-MRI),with 8 channels head ciol.13 patients were excluded(seven patients with image artifact and six patients for their vertebrobasilar geometry could not be classified),ultimately,290 patients were included in our study.The sequences included conventional MR imaging sequences,3D TOF-MRA and 3D CUBE-T1WI.The vertebrobasilar artery geometry was qualitatively classified into four basic configurations:Walking,Tuning Fork,Lambda,and No Confluence.The diameter of each vertebral artery(VA)was measured and the bending number of bilateral vertebral artery intracranial segment was assessed.To Observe basilar artery wall and determine weather there is plaque formation.Incidence of basilar artery plaque were compared among patients with different vertebrobasilar geometries,and comparison of plaque incidence in basilar artery was also performed among patients with different vascular bending number of bilateral vertebral artery intracranial segment.The relationship between the diameter difference of bilateral vertebral artery and basilar artery plaque initiation in the vertebrobasilar artery with Lambda configuration was also analyzed.Results:There were 49 patients in the vertebrobasilar artery with Walking configuration,and plaque was identified in 26 patients(53.06%),there were 73patients in the vertebrobasilar artery with Tuning Fork confugration,and plaque was identified in 11 patients(15.07%),there were 144 patients in the vertebrobasilar artery with Lambda confugration,and plaque was identified in 40patients(27.78%),there were 24 patients in the vertebrobasilar artery with No Confluence confugration,and plaque was identified in 9 patients(37.50%),there was significant difference in plaque incidence of basilar artery among the four basic geometric configurations(?~2=21.265,P<0.001).In Walking group,there were28 patients with bending number?3 and 21 patients with bending number<3 in intracranial segment of bilateral vertebral artery,plaque was identified in 20patients(71.43%)and 6 patients(28.57%)respectively,there was significant difference in the plaque incidence of basilar artery between the two groups(?~2=8.849,P=0.003).In Tuning Fork group,there were 4 patients with bending number?3 in intracranial segment of bilateral vertebral artery and none patient found plaque,there were 69 patients with bending number<3 in intracranial sagement of bilateral vertebral artery,plaque was identified in 11 patients(15.94%),there was no significant difference in the plaque incidence of basilar artery between the two groups(P=1.000).In Lambda group,there were 47 patients with bending number?3 and 97 patients with bending number<3 in intracranial segment of bilateral vertebral artery,plaque was identified in 19 patients(40.43%)and 21patients(21.65%)respectively,there was significant difference in the plaque incidence of basilar artery between the two groups(?~2=5.563,P=0.018).In No Confluence group,bending number<3 in intracranial segment of bilateral vertebral artery were happened in all patients.In Lambda group,the diameter difference of bilateral vertebral artery was 1.4mm(0.9mm,-1.6mm)in patients with basilar artery plaque and 0.9mm(0.6mm-1.3mm)in patients without basilar artery plaque(P<0.001).Conclusions:Vertebrobasilar artery has various vascular configurations.Factors influenceing basilar artery plaque initiation including:different vertebrobasilar artery geometries(Walking,Lambda,No Confluence),bending number?3 in intracranial segment of bilateral vertebral artery,and the diameter difference of bilateral vertebral artery.Part 2 Relationship between Basilar Artery Plaque Distribution and Pontine Infarction and the Influence of Vertebrobasilar Geometry on Basilar Artery Plaque DistributionObjective: To investigate the relationship between basilar artery plaque distribution and pontine infarction and the influence of different vertebrobasilar geometries on basilar artery plaque distribution.Material and Method: Eighty-six patients diagnosed with posterior ischemic stroke were enrolled,one patient for vertebrobasilar geometry could not be classified was excluded.All subjects had basilar artery plaque at least one section on 3D CUBE-T1 WI.Each basilar artery cross-section was grouped into four quadrants(anterior,posterior,left and right wall),to observe the basilar artery plaque distribution on each cross-section,and calculate the percentage of plaque dnistribution at anterior,posterior and lateral side of basilar wall.Acute and subacute pontine ischemic lesios were identified on T2WI-FLAIR and DWI,and analyze the relationship between basilar artery plaque distribution and pontine infarction(PI).On 3D TOF-MRA,Vertebrobasilar geometry was classified into four geometric configurations:Walking,Tuning Fork,Lambda,No Confluence,AP-Mid-BA angle?VA-BA angle and Lateral-Mid-BA angle were also measured on MRA.To explore the influence of Vertebrobasilar geometry on basilar artery plaque distribution and compare the differences of the three angles among the four vascular geometries.Results: The percentage of basilar artery plaque distribution in anterior,posterior and lateral walls in 86 patients was 19.09%(0%-42.86%),27.92%(0%-50.00%)and 48.53%(33.33%-66.67%),respectively(?2=24.213,P<0.001).The percentage of plaque distribution in anterior,posterior and lateral walls in 13 patients with pontine infarction(PI)was 10.00%(0%-38.18%),50.00%(23.64%-66.67%)and 37.50%(31.67%-54.17%),respectively(?2=7.125,P=0.028).The percentage of plaque distribution in anterior,posterior and lateral walls in 73 patients without PI was 20.00%(0%-50.00%),22.22%(0%-46.06%)and 50.00%(33.33%-66.67%),respectively(?2=22.740,P<0.001).The percentage of basilar artery plaque distribution in posterior walls in patients with PI was higher than that in patients without PI(P=0.009),there was no significant difference in plaque distribution in anterior and lateral walls between patients with or without pontine infarction(P>0.05).The percentage of plaque distribution in anterior,posterior and lateral walls in 26 patients with Walking confugration was 15.34%(0%-42.86%),27.92%(0%-51.79%)and 47.73%(32.50%-66.67%),respectively(?2=7.936,P=0.019).The percentage of plaque distribution in anterior,posterior and lateral walls in patients with Tuning Fork confugration was 13.64%(0%-50.00%),37.50%(0%-66.67%)and 37.50%(0%-90.91%),respectively(?2=2.667,P=0.264).The percentage of plaque distribution in anterior,posterior and lateral walls in patients with Lambda confugration was 25.00%(0%-50.00%),24.35%(2.94%-48.44%)and 48.53%(34.38%-63.35%),respectively(?2=10.792,P=0.005).The percentage of plaque distribution in anterior,posterior or lateral walls in patients with No Confluence confugration was 11.11%(0%-33.18%),30.00%(12.42%-50.00%)and 50.00%(36.51%-80.00%),respectively(?2=6.061,P=0.048).AP-Mid-BA angle in patients with Walking confugration(36.130±18.270)was higher than that in patients with other vascular geometries(F=6.394,P=0.001),there was no significant difference in VA-BA angle and Lateral-Mid-BA angle among the four vertebrobasilar geometries(P>0.05).Conclusions: Pontine infarction(PI)maybe related to BA Plaque distribution.The probability of plaque distribution at the posterior walls in patients with PI was significantly increased;moreover,different vertebrobasilar geometries may be have influence on BA plaque distribution,the probability of plaque distribution at the lateral walls in patients with Walking,Lambda and No Confluence geometry was higher than that in patients with Tuning Fork confugration. |
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