Department of Neurology, School of Medicine, Ajou University, Suwon, Republic of Korea.
J Clin Neurosci. 2010 Dec;17(12):1506-9. doi: 10.1016/j.jocn.2010.03.050.
The aim of this study was to develop a simple and reliable sign for detecting proximal internal carotid artery occlusion (ICAO) using conventional CT scanning. The missing button sign (MBS) is defined as the absence of the ICA at the level of the foramen magnum on contrast-enhanced CT (CECT) scans. Two raters independently reviewed random CECT samples from consecutive patients with acute ischaemic stroke. A total of 399 patients with 798 carotid arteries were analysed. Rater A identified the MBS in 41 (5%) of the carotid arteries, and did not identify the MBS in 735 (92%) carotid arteries. Rater B identified the MBS in 45 (6%) of the arteries, and lack of the MBS in 731 (91%) arteries. The kappa value for agreement was 0.90 (95% CI 0.84-0.95). Compared with CT angiography, Rater A's sensitivity, specificity, positive predictive value, and negative predictive value for detecting proximal ICAO were 85%, 100%, 100%, and 99%, respectively, while Rater B's values were 87%, 99%, 93%, and 99%, respectively. This study indicated that the MBS on CECT scanning is both a consistent and specific tool for the early identification of proximal ICAO.
本研究旨在开发一种使用常规 CT 扫描检测近端颈内动脉闭塞（ICAO）的简单可靠的征象。缺失按钮征（MBS）定义为增强 CT（CECT）扫描时在枕骨大孔水平颈内动脉缺失。两位评估者独立回顾了连续急性缺血性脑卒中患者的随机 CECT 样本。共分析了 399 例患者的 798 条颈动脉。评估者 A 在 41 条（5%）颈动脉中识别出 MBS，在 735 条（92%）颈动脉中未识别出 MBS。评估者 B 在 45 条（6%）动脉中识别出 MBS，在 731 条（91%）动脉中未识别出 MBS。一致性的kappa 值为 0.90（95%CI 0.84-0.95）。与 CT 血管造影相比，评估者 A 检测近端 ICAO 的灵敏度、特异性、阳性预测值和阴性预测值分别为 85%、100%、100%和 99%，而评估者 B 的分别为 87%、99%、93%和 99%。本研究表明，CECT 扫描上的 MBS 是早期识别近端 ICAO 的一种一致且特异的工具。
