Table_2_Validation of two automated ASPECTS software on non-contrast computed tomography scans of patients with acute ischemic stroke.DOCX

PurposeThe Alberta Stroke Program Early Computed Tomography Score (ASPECTS) was designed for semi-quantitative assessment of early ischemic changes on non-contrast computed tomography (NCCT) for acute ischemic stroke (AIS). We evaluated two automated ASPECTS software in comparison with reference standard.
MethodsNCCT of 276 AIS patients were retrospectively reviewed (March 2018–June 2020). A three-radiologist consensus for ASPECTS was used as reference standard. Imaging data from both baseline and follow-up were evaluated for reference standard. Automated ASPECTS were calculated from baseline NCCT with 1-mm and 5-mm slice thickness, respectively. Agreement between automated ASPECTS and reference standard was assessed using intra-class correlation coefficient (ICC). Correlation of automated ASPECTS with baseline stroke severity (NIHSS) and follow-up ASPECTS were evaluated using Spearman correlation analysis.
ResultsIn score-based analysis, automated ASPECTS calculated from 5-mm slice thickness images agreed well with reference standard (software A: ICC = 0.77; software B: ICC = 0.65). Bland–Altman analysis revealed that the mean differences between automated ASPECTS and reference standard were ≤ 0.6. In region-based analysis, automated ASPECTS derived from 5-mm slice thickness images by software A showed higher sensitivity (0.60 vs. 0.54), lower specificity (0.91 vs. 0.94), and higher AUC (0.76 vs. 0.74) than those using 1-mm slice thickness images (p < 0.05). Automated ASPECTS derived from 5-mm slice thickness images by software B showed higher sensitivity (0.56 vs. 0.51), higher specificity (0.87 vs. 0.81), higher accuracy (0.80 vs. 0.73), and higher AUC (0.71 vs. 0.66) than those using 1-mm slice thickness images (p < 0.05). Automated ASPECTS were significantly associated with baseline NIHSS and follow-up ASPECTS.
ConclusionAutomated ASPECTS showed good reliability and 5 mm was the optimal slice thickness.

### 研究目的
阿尔伯塔卒中项目早期CT评分（Alberta Stroke Program Early Computed Tomography Score, ASPECTS）最初用于对半定量评估急性缺血性卒中（acute ischemic stroke, AIS）患者非增强计算机断层扫描（non-contrast computed tomography, NCCT）上的早期缺血性改变。本研究旨在对比两款自动化ASPECTS评分软件与参考标准的评估效能。

### 研究方法
本研究回顾性分析了2018年3月至2020年6月期间的276例急性缺血性卒中患者的非增强CT影像。由3名放射科医师达成的ASPECTS共识评分作为参考标准，参考标准的评估涵盖基线及随访阶段的影像学数据。分别采用层厚1mm与5mm的基线NCCT影像计算自动化ASPECTS评分。采用组内相关系数（intra-class correlation coefficient, ICC）评估自动化ASPECTS与参考标准的一致性。采用斯皮尔曼相关分析评估自动化ASPECTS与基线卒中严重程度（美国国立卫生研究院卒中量表, National Institutes of Health Stroke Scale, NIHSS）及随访ASPECTS评分的相关性。

### 研究结果
评分层面分析显示，基于5mm层厚影像计算的自动化ASPECTS与参考标准一致性良好（软件A：ICC=0.77；软件B：ICC=0.65）。布兰德-奥特曼（Bland-Altman）分析法显示，自动化ASPECTS与参考标准的平均差值≤0.6。区域层面分析显示，软件A基于5mm层厚影像生成的自动化ASPECTS较1mm层厚影像组具有更高的灵敏度（0.60 vs 0.54）、更低的特异度（0.91 vs 0.94）及更高的曲线下面积（Area Under Curve, AUC, 0.76 vs 0.74），组间差异均具有统计学意义（p<0.05）。软件B基于5mm层厚影像生成的自动化ASPECTS较1mm层厚影像组具有更高的灵敏度（0.56 vs 0.51）、更高的特异度（0.87 vs 0.81）、更高的准确率（0.80 vs 0.73）及更高的曲线下面积（Area Under Curve, AUC, 0.71 vs 0.66），组间差异均具有统计学意义（p<0.05）。自动化ASPECTS评分与基线NIHSS评分及随访ASPECTS评分均呈显著相关。

### 研究结论
自动化ASPECTS评分具有良好的可靠性，且5mm层厚为最优扫描层厚。