Brain Ventricular Size in Healthy Elderly: Comparison Between Evans Index and Volume Measurement
Brain Ventricular Size in Healthy Elderly: Comparison Between Evans Index and Volume Measurement
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DOI：
10.1227/01.neu.0000370939.30003.d1
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发表时间：
2010-07-01
期刊：
影响因子：
4.8
通讯作者：
Malm, Jan
中科院分区：
文献类型：
--
作者：
Ambarki, Khalid;Israelsson, Hanna;Malm, Jan
背景：脑室增大的精确定义对于脑积水的诊断以及评估中枢萎缩非常重要。Evans指数（EI）是最大额角宽度与颅骨直径之间的线性比值，已被广泛用作心室容积（VV）的间接标志。借助现代成像技术，可以直接测量脑容量。目的：确定健康老年人颅内容积的参考值，并探讨其与EI的相关性。方法：对46例健康老年白人（平均年龄+/-标准差71 +/- 6岁）和20例目测大脑室患者（74 +/- 7岁）进行磁共振成像（3t）检查。评估VV、相对VV （relative VV， RVV）和EI。使用VV和EI来定义心室扩张，其值高于健康老年人的第95个百分位范围。结果：健康老年人VV = 37 +/- 18 mL, RVV = 2.47 +/- 1.17%, EI = 0.281 +/- 0.027。包括患者在内，EI与VV （R = 0.94）、EI与RVV （R = 0.95）均有较强的相关性。然而，由于95%的预测区间很宽（VV: +/- 45 mL; RVV: +/- 2.54%）， EI并没有给出足够好的VV和RVV的估计。结论：VV（或RVV）与EI表现出不同的性质。在临床研究中单独使用EI作为心室增大的标志应该受到质疑。我们建议白人老年人心室扩张的定义为VV >≥77 mL或RVV >≥4.96%。未来的研究应将颅内容积与临床特征和预后进行比较。
BACKGROUND: A precise definition of ventricular enlargement is important in the diagnosis of hydrocephalus as well as in assessing central atrophy. The Evans index (EI), a linear ratio between the maximal frontal horn width and the cranium diameter, has been extensively used as an indirect marker of ventricular volume (VV). With modern imaging techniques, brain volume can be directly measured.OBJECTIVE: To determine reference values of intracranial volumes in healthy elderly individuals and to correlate volumes with the EI.METHODS: Magnetic resonance imaging (3 T) was performed in 46 healthy white elderly subjects (mean age +/- standard deviation, 71 +/- 6 years) and in 20 patients (74 +/- 7 years) with large ventricles according to visual inspection. VV, relative VV (RVV), and EI were assessed. Ventricular dilation was defined using VV and EI by a value above the 95th percentile range for healthy elderly individuals.RESULTS: In healthy elderly subjects, we found VV = 37 +/- 18 mL, RVV = 2.47 +/- 1.17%, and EI = 0.281 +/- 0.027. Including the patients, there was a strong correlation between EI and VV (R = 0.94) as well as between EI and RVV (R = 0.95). However, because of a wide 95% prediction interval (VV: +/- 45 mL; RVV: +/- 2.54%), EI did not give a sufficiently good estimate of VV and RVV.CONCLUSION: VV (or RVV) and the EI reflect different properties. The exclusive use of EI in clinical studies as a marker of enlarged ventricles should be questioned. We suggest that the definition of dilated ventricles in white elderly individuals be defined as VV > 77 mL or RVV > 4.96 %. Future studies should compare intracranial volumes with clinical characteristics and prognosis.