Neuroimaging And Prognostic Analysis Of The Top Of The Basilar Syndrome

PartⅠNeuroimaging of the top of the basilar syndromeObjective To investigate the distribution of infarctions, vascular lesions, pathogenesis and prognosis of top of the basilar syndrome (TOBS).Methods Twenty-one patients with top of basilar artery syndrome were selected and analyzed From Nanjing Stroke Registration Program(NSRP) between January 2004 to May 2009. Each patient gave informed consent to prior to digital subtraction angiography (DSA) within after admission. Inclusion criteria were:(1) all patients met the diagnostic criteria established by Fourth National Cerebrovascular Disease Conference; (2) typical clinical manifestations were presented, such as sudden disturbance of consciousness, oculomotor, and behavioral abnormalities, but motor and sensory abnormalities may be relatively mild; (3)using brain CT or MRI scan, it showed there were not simultaneously less than two locations of infarctions among the thalamus, midbrain, cellebellum, occipital and temporal lobes. To investigate the topographic characteristics of infarcts on top of the basilar syndrome, we used the Adobe Fireworks CS 4.0 to overlap the figures of ischemic lesions on a representative brain outline background by the following steps. First, we selected an MR image which was derived from a normal person and made the outline of the brain as the background. The figures of ischemic lesions on DWI of each patient were extracted and filled with black. Each figure was pasted as a new layer on the corresponding background. Finally, after adjusting the opacity to 30%, all the infarct scan layers were merged to background. Cerebral digital subtraction angiography (DSA) was performed using the Seldinger technique. Degree of extracranial and intracranial arterial stenosis was calculated according to the NASCET and WASID method respectively. The maximal diameter of stenosis was measured and categorized as mild(0-29%), moderate(30-69%), severe (70-99%)and occlusive(100%). The images were analyzed by two neuroradiologists and two neurologists using the NASCET criteria, separately. According to the New England Medical Center Posterior Circulation Registry, stroke mechanisms were as follows:(1) Large artery occlusive disease-hemodynamic mechanism, (2). Embolism, (3) Branch artery occlusive disease, and (4) other or unkown cause. Statistical analysis was performed using SPSS version 13.0. Continuous parameter data were presented for means±SD. Chi square analysis was used for dichotomous results (Fisher's exact test). P<0.05 was considered to be statistically significant.Results (1) By Brain MRI, we found that 21 TOBS patients with a total of 82 ischemia lesions lied in posterior circulation and the average number of lesions were 3.9 in each patient. These lesions located mainly in the thalamus (76.2%), midbrain (66.7%), occipital lobe (52.4%), cerebellum (47.6%), and medial temporal lobe (23.8%). The occurrence of ischemia lesions in various parts have significant difference (P=0.009), The lesions located in thalamus and midbrain, were more concentrated than those located in other areas supplied by posterior circulation. (2) Cerebral angiography found 20 in 21 patients had vertebrobasilar artery disease, one patient with normal vertebrobasilar artery. Among them,19 patients had atherosclerotic pathological changes in posterior circulation, including plaques, vascular stenosis and occlusion, one patient with vascular variant (isolated vertebral artery). We found a total of 19 vascular lesions in all patients, more concentrated in the distal BA (57.1%) and intracranial vertebral artery (52.4%), than other parts of the posterior circulation (P<0.01);Degree of artery stenosis tend to severe stenosis (25.0%) or occlusion (59.4%). (3) The most possible pathogenesis of TOBS were large artery occlusive-hemodynamic mechanism (52.4%) or embolization mechanism (42.9%).Conclusions TOBS simultaneously comprise multi-infarctions involving many territories in posterior circulation. Thalamus and midbrain were the predilection sites. Atherosclerotic stenoses or occlusions of vascular lesions are mainly located in distal BA and intracranial vertebral artery. The most possible pathogenesis of TOBS was large artery occlusive-hemodynamic mechanism or embolization mechanism. Diagnosis TOBS mainly rely on brain MRI, while cerebral angiography has most important significance in defecting location of vascular occlusion. Earlier check of MRI or DSA for clinical patient who is suspected have the TOBS could help making correct diagnosis, so the patient can receive treatment promptly. PartⅡPrognostic Value of GCS and NIHSS in Patients with Top ofthe Basilar artery SyndromeObjective To assess the effectiveness of initial Glasgow Coma Scale (GCS) and National Institutes of Health Stroke Scale (NIHSS) as predictors for clinical outcomes in patients with Top of the Basilar artery Syndrome(TOBS).Patients and Methods A total of 64 patients with TOBS were selected from Nanjing Stroke Registration Program (NSRP). Initial GCS and NIHSS were retrospectively evaluated by reviewing patients'records for details of clinical presentation and outcome at 30 days measured by modified Rankin Scale (mRS) score. Patients were categorized as favorable outcome group (mRS 0-3) and unfavorable outcome group (mRS 4-6). Glasgow Coma Scale (GCS) is a neurological scale that aims to give a reliable, objective way of recording the conscious state of a person for initial as well as subsequent assessment. The scale comprises three tests:eye, verbal and motor responses. Selected the best response to the verdict of the points; motor score left the right side may be different, with higher scores score. The three values separately as well as their sum are considered. The lowest possible GCS (the sum) is 3 (deep coma or death), while the highest is 15 (fully awake person). The National Institutes of Health Stroke Scale (or NIHSS) is a method developed by the National Institutes of Health. It is used to gauge the severity of a stroke including consciousness, gaze, facial paralysis, motor arm, motor leg, ataxia, aphasia, dysarthria, sensation, vision, neglect, etc., with total score of 35 points. Scores should reflect what the patient does, not what the clinician thinks the patient can do. The clinician should record answers while administering the exam and work quickly. Except where indicated, the patient should not be coached (i.e., repeated requests to patient to make a special effort). The modified Rankin Scale (mRS) is a commonly used scale for measuring the degree of disability or dependence in the daily activities of people who have suffered a stroke, The scale runs from 0-6, running from perfect health without symptoms to death. Statistical analysis was performed utilizing SPSS version 13.0. Continuous parameter data were summarized as means±SD. Means of parameter data were compared using t-test (two groups) or one-way ANOVA(≥three groups). Chi square analysis was used for dichotomous results. Spearman rank correlation coefficient was used to examine the relation between the lesion grading and admission GCS and NIHSS. Using logistic regression analysis to evaluate predictive GCS and NIHSS value for poor outcome (adjusted age, sex and treatment). ROC curves was used to assess the accuracy of predict test. P<0.05 was considered statistically significant.Results The mean GCS was lower in the cases with mRS of 4-6 compared with those with mRS of 0-3 (P<0.01) and the mean NIHSS score was higher in the poor outcome group in contrast to the good one (P=0.01). In multivariate logistic regression analysis, after adjusting for age, gender and treatment approaches, the GCS OR was 0.301 (95% CI 0.167-0.542), NIHSS OR was 1.436 (95% CI 1.147-1.796), and both of them turned out to be the independent predictors of outcome at 30 days. ROC curve analysis suggested that GCS score of 10 represented a good cut-off point for predicting the outcome with the prognostic sensitivity of 87.9% and specificity of 83.9%. NIHSS score of 14 could also serve as a good cut-off point with the prognostic sensitivity of 63.6% and specificity of 77.4%.Conclusions Both GCS and NIHSS can predict outcomes in patients with acute TOBS with GCS score≤10 and NIHSS score≥14 as the cutoff points of poor outcome. GCS cutoff point is more strongly predictive of outcome than that of NIHSS.