PURPOSE To recommend a new simple and explicit index termed the anteroposterior diameter of the lateral ventricle index (ALVI) for assessing brain ventricular size in neuroimaging and to compare Evans index (EI) between idiopathic normal pressure hydrocephalus (iNPH) patients and age-matched healthy elderly subjects. METHODS Retrospective measurements of ventricular volume (VV), relative VV (RVV), the EI, and the ALVI were taken from thin-section CT scans for 23 pre-shunt-insertion iNPH patients and 62 age-matched healthy elderly volunteers. The area under the receiver operating characteristic (ROC) curve (AUC), net reclassification improvement (NRI), and integrated discrimination improvement (IDI) were calculated to assess the effectiveness of ALVI scores for predicting VV. RESULTS The correlations between VV or RVV and ALVI scores (VV, r = 0.957; RVV, r = 0.983) were significantly stronger than the corresponding correlations with EI scores (VV, r = 0.843; RVV, r = 0.840). The AUC for ALVI scores was significantly greater than the AUC for EI scores. Furthermore, with the inclusion of the ALVI, the NRI value was 0.14 and the IDI value was 0.14; these improvements were also statistically significant. CONCLUSION The ALVI is a more accurate and more explicitly defined marker of VV than the EI and assesses ventricular enlargement effectively. We suggest that ventricular enlargement of the healthy elderly be defined by ALVI > 0.50.

中文翻译：

---

一种评估特发性常压脑积水的脑室容量的新指标：与Evans指标的比较。

目的推荐一种新的简单而明确的指标，称为侧脑室前后直径（ALVI），以评估神经影像学中的脑室大小，并比较特发性正常压力脑积水（iNPH）患者和与年龄相匹配的健康者之间的Evans指数（EI）老年受试者。方法回顾性分析了23例分流插管iNPH患者和62例年龄相匹配的健康老年志愿者的心室容积（VV），相对VV（RVV），EI和ALVI。计算接收器工作特性（ROC）曲线（AUC），净重分类改进（NRI）和综合辨别改进（IDI）下的面积，以评估ALVI评分预测VV的有效性。结果VV或RVV与ALVI得分之间的相关性（VV，r = 0。957；RVV，r = 0.983）明显强于与EI评分的相应相关性（VV，r = 0.843； RVV，r = 0.840）。ALVI分数的AUC显着大于EI分数的AUC。另外，在包含ALVI的情况下，NRI值为0.14，IDI值为0.14。这些改善也具有统计学意义。结论ALVI是比EI更准确，更明确定义的VV标记，可有效评估心室扩大。我们建议将健康老年人的心室扩大定义为ALVI> 0.50。NRI值为0.14，IDI值为0.14。这些改善也具有统计学意义。结论ALVI是比EI更准确，更明确定义的VV标记，可有效评估心室扩大。我们建议将健康老年人的心室扩大定义为ALVI> 0.50。NRI值为0.14，IDI值为0.14。这些改善也具有统计学意义。结论ALVI是比EI更准确，更明确定义的VV标记，可有效评估心室扩大。我们建议将健康老年人的心室扩大定义为ALVI> 0.50。