| ObjectiveObserve the cerebralvascular and carotid conditions and perliminarily study the differences between the anterior and posterior circulations to evaluate hemodynamics of the posterior circulation system in posterior circulation ischemia (PCI) patients with cerebellar hemisphere and centrum semiovale white matter as an example by320-slice CT angiography and CT perfusion imaing, aiming to explore the clinical value of320-slice CT in PCIMethodsSelect29PCI patients in the Department of Neurology of Wuhan General Hospital of Guangzhou Military Region as the PCI group, while27normal subjects and CTA confirmed with no cerebralvascular and carotid diseases as the control group. All objects underwent head and neck CT angiography, the whole brain CT perfusion by320-slice CT. The cerebralvascular and carotid conditions were observed. In PCI group with the cerebral vascular stenosis, bilateral cerebellar hemisphere were chosed as the region on behalf of the posteriror circulation,while bilateral centrum semiovale white matter on behalf of the anterior circulation system. Three lcm2regions of interest (ROIs) were manually seted on each perfusion map of the cerebellar hemisphere and centrum semiovale white matter. TTP, MTT, CBF, CBV of each ROI was measured. The ROIs of the cerebellar hemisphere and ispilateral centrum semiovale white matter were randomly paired.△TTP,△MTT,△CBF,△CBV between the the cerebellar hemisphere and the ispilateral centrum semiovale white matter were obtained.△TTP,△MTT,△CBF,△CBV were obtained in the control group by the same method. Two sets of the△TTP,△MTT,△CBF,△CBV were statstically analyzed and explore the feasibility of this method to distinguish the normal and abnormal cerebellar hemisphere perfusion areas.Results1CTA1.1A total of23cases (79.31%) had intranical or extracranial arterial stenosis in the posteriror circulation, while6cases (20.69%)showing no definitely artery stenosis in the PCI group.In which,18cases (62.07%) had wide range of stenosis,5cases had a single stenosis.5cases (17.24%)showed unilateral VA lesions,11cases (37.93%) showed bilateral VA lesions,13cases (44.83%) showed BA lesions,2cases (6.9%)showed unilateral PCA lesions,5cases (17.24%) showed bilateral PCA lesions;3cases (10.24%) showed unilateral SCA lesions. A total of57artery lesions were found.1.2A total of7cases (24.14%)had unilateral vertebral artery hypoplasia in the PCI group.7cases (25.93%) had unilateral vertebral artery hypoplasia in the control group. There was no significnant diffrence between the two group (x2=0.024, P=0.877).1.3A total of2cases(6.90%) had bilateral vertebral artery oppression by bone and2cases (6.90%)had vertebral artery tortuosity in PCI group, while3cases (11.11%) had bilateral vertebral artery oppression and no case had had vertebral artery tortuosity in the control group. There was no significant diffrence between the two groups (x2c=0.000, P=1.000)1.4A total of14cases (48.28%) showed unilateral or bilateral posterior communicating artery open,while7caes (25.93%)in the control group. There was asignificant diffrence between the two groups (P＜0.05).2CTPI2.1The△TTP,△MTT,△CBF,△CBV was (1.42±2.23) s,(0.62±1.02) s,(10.98±9.40)ml/(100g min),(1.18±0.92) ml/100g in the PCI group accompanied by cerebellar artery stenosis,while (0.05±0.62) s,(0.18±0.71) s,(6.20±9.16) ml/(100g·min),(0.48±0.90) ml/100g in the control group.△TTP,△MTT,△CBF,△CBV in the PCI group accompanied by cerebellar artery stenosis was higher than in the control group (P<0.05)2.2By discriminant analysis, the best thresholds of△TTP,△MTT,△CBF and△CBV to determine normal and abnormal cerebellar hemisphere threshold was0.74s,0.5s,8.6ml/(100g·min),0.9ml/100g, when each of them as a single predictor. The idstinguish coincidence rate was75.7%,66.7%,64.7%,67%respectively. By the ROC curve analysis,△TTP showed the largest area under the curve, up to76.9%, tipping as a single definition of indicator,△TTP was superior than△MTT,△CBV and△CBF. when△TTP threshold is equal to0.74s, the sensitivity was60%and thesecificity was87%.2.3240ROIs in the PCI group accompanied by cerebellar artery stenosis were reclassfied by△TTP method and the contralateral mirror method, respectively, we found the△TTP method could distinguish144abnormal ROIs and the contralateral mirror method could distinguish45abnormalROIs,the detection rates of the two group was60%and18.75%, respectively, through x2analysis, the detection rates of the△TTP method was higher than the contra lateral mirror method(x2=9.231,P＜0.05)。Tip in PCI patients, the△TTP method was superior to the contralateral mirror method for distinguishing the abnormal perfusion.Conclusions179.31%of PCI patients had vascular stenosis in the posterior circulation system. Atherosclerosis was the major course of PCI. Vertebral artery hypoplasia, disorted, bone oprression was not the direct cause of PCI. Posterior communicating artery openning was common in PCI patients, play partly compensatory role2The△TTP,△MTT,△CBF,△CBV between the the cerebellar hemisphere and the ispilateral centrum semiovale white matter can perdict the cerebellar hymodynamic changes. The△TTP was the best prdictor, the best threhold of△TTP was0.74s. The difference of perfusion parameters bwtween the anterior and posterior circulation was feasible to reflect the hymodynamic changes of posterior circulation.3The320-slice CTA and CTPI had importrant helpful diagnostic value for PCI. |
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