Kobkitsuksakul Chai, Tritanon Oranan, Suraratdecha Vichan
Division of Interventional Neuroradiology, Ramathibodi Hospital, Mahidol University School of Medicine, Bangkok, Thailand.
Department of Diagnostic and Therapeutic Radiology, Ramathibodi Hospital, Mahidol University School of Medicine, Bangkok, Thailand.
Diagn Interv Radiol. 2018 Mar-Apr;24(2):104-107. doi: 10.5152/dir.2018.17336.
The distribution of ischemic changes caused by infarction of the middle cerebral artery (MCA) territories is usually measured using the Alberta Stroke Program Early Computed Tomography Score (ASPECTS). The first interpreter of the brain computed tomography (CT) in the emergency department is the on-call radiology resident. The primary objective of this study was to describe the agreement of the ASPECTS performed retrospectively by the resident compared with expert raters. The second objective was to ascertain the appropriate window setting for early detection of acute ischemic stroke and good interobserver agreement between the interpreters.
We identified consecutive patients presenting with hemiparesis or aphasia at the emergency department who underwent brain CT and CT angiography. Each scan was rated using ASPECTS by senior radiology resident, neuroradiology fellow, and later by consensus between two expert raters. Statistical analysis included determination of Cohen's kappa (κ) coefficient and intraclass correlation coefficient (ICC).
A total of 43 patients met our study criteria. Interobserver agreements for ASPECTS varied from 0.486 to 0.678 in Cohen's κ coefficient between consensus of two neuroradiologists and a neuroradiology fellow, and from 0.198 to 0.491 for consensus between two neuroradiologists and a senior radiology resident. ICC among three raters (expert consensus, neuroradiology fellow, and senior radiology resident), was very good when 8 HU window width and 32 HU center level setting was used.
ASPECTS varied among raters. However, when using a narrowed window setting for interpretation, interobserver agreement improved.
大脑中动脉（MCA）供血区梗死所致缺血性改变的分布通常采用阿尔伯塔卒中项目早期计算机断层扫描评分（ASPECTS）进行测量。急诊科脑计算机断层扫描（CT）的首位解读人员是值班放射科住院医师。本研究的主要目的是描述住院医师与专家评估者进行回顾性ASPECTS评分的一致性。第二个目的是确定早期检测急性缺血性卒中的合适窗宽设置以及解读人员之间良好的观察者间一致性。
我们确定了在急诊科因偏瘫或失语就诊并接受脑CT和CT血管造影的连续患者。每次扫描均由放射科高级住院医师、神经放射科住院医师使用ASPECTS进行评分，随后由两名专家评估者达成共识进行评分。统计分析包括确定科恩kappa（κ）系数和组内相关系数（ICC）。
共有43例患者符合我们的研究标准。两名神经放射科医生与一名神经放射科住院医师达成共识时，ASPECTS的观察者间一致性在科恩κ系数中为0.486至0.678，两名神经放射科医生与一名放射科高级住院医师达成共识时为0.198至0.491。当使用8 HU窗宽和32 HU中心水平设置时，三名评估者（专家共识、神经放射科住院医师和放射科高级住院医师）之间的ICC非常好。
ASPECTS在评估者之间存在差异。然而，在使用较窄窗宽设置进行解读时，观察者间一致性有所提高。
