椎动脉发育不良对老年后循环小梗死患者早期磁共振成像假阴性率的影响

Effect of vertebral artery hypoplasia on false negative rates in early MRI detection of small posterior circulation infarcts in elderly patients

目的 探讨椎动脉发育不良（VAH）对表现为急性孤立性前庭综合征的老年后循环小梗死（头颅MRI-DWI轴位梗死直径≤10 mm）患者早期磁共振成像（MRI）假阴性率的影响. 方法 连续入选224例老年高危急性孤立性前庭综合征（合并≥1个血管危险因素）患者进行前瞻性观察.尽可能在头颅MRI-DWI完成前进行头脉冲、凝视诱发眼震、眼偏斜（HINTS）＋脑干听觉诱发电位（BAEP）＋瞬目反射（BR）检查,对早期DWI正常而HINTS＋ BAEP十BR检查策略怀疑中枢损害的患者72 h后复查DWI.把患者分为VAH组和非VAH组. 结果 98例患者发生后循环梗死,其中小梗死37例,VAH组16例（16/61,26.2％）,非VAH组21例（21/163,12.9％）,差异有统计学意义（x2 =4.58,P＜0.05）.头颅MRI-DWI假阴性患者,VAH组9例（9/16,56.3％）,非VAH组4例（4/21,19.0％）,差异有统计学意义（x2=6.23,P＜o.001）.HINTS＋ BAEP＋ BR对筛查小梗死的敏感性与早期头颅MRI-DWI比较,VAH组（100.0％比44.0％,U=6.41,P＜0.001）,非VAH组（100.0％比81.0％,U=4.46,P＜0.05）.VAH组BAEP的Ⅴ波峰潜伏期、Ⅲ～Ⅴ、Ⅰ～Ⅴ波间潜伏期以及BR的R1及R2、R2＇潜伏期均较非VAH组延长,差异有统计学意义（均P＜0.05）. 结论 老年高危急性孤立性前庭综合征患者,存在VAH时合并小梗死发生率高,MRI-DWI早期假阴性发生率高,HINTS＋ BAEP＋ BR检查策略有助于提高诊断敏感性.

Objective To explore the effects of vertebral artery hypoplasia （VAH）on falsenegative rates with MRI in isolated acute vestibular syndrome （AIVS） patients with small posterior circulation small infarcts （infarct diameter ≤ 10 mm by DWI）.Methods A total of 224 AIVS patients with at least one stroke risk factor （defined as high-risk AIVS）were consecutively recruited.Head impulse,nystagmus and test-of-skew（HINTS）,brainstem auditory evoked potential （BAEP）,and blink reflex（BR）were performed as soon as possible ahead of MRI.Another MRI was carried out in those with negative findings on the first imaging but suspected of a central lesion based on HINTS ＋ BAEP ＋ BR.Patients were divided into a VAH group and a non-VAH group.Results Of the 98 cases with posterior circulation infarcts,37 cases were small infarcts,including 16 in the VAH group（16/61,26.2%）and 21 in the non VAH group（21/163,12.9%）,with a significant difference between the groups（x2 =4.58,P 〈 0.05）.Nine VAH patients （9/16,56.3 %）and 4 non-VAH patients（4/21,19.0%）presented false negative results on cranial MRI-DWI,and the difference was also statistically significant（x2 =6.23,P〈0.001）.HINTS ＋ BAEP ＋ BR showed a higher sensitivity than early MRI in identifying small infarcts（VAH group：100.0% vs.44.0% or 7/16,U=6.41,P〈0.001;non-VAH group：100.0% vs.81.0% or 17/21,U=4.46,P〈0.0S）.V wave peak latency,Ⅲ-Ⅴ and Ⅰ-Ⅴ wave interpeak latency,and the latency of R1,R2,and R2＇ in the VAH group were longer than in the non-VAH group（each P〈0.05）.Conclusions When VAH is present in high-risk AIVS patients,small infarcts are common,with high false-negative rates on MRI-DWI.HINTS ＋ BAEP ＋ BR may help identify small infarcts and thus improve diagnostic sensitivity.