Ng Him Shing, Hao Qing, Leung Thomas, Lawrence Wong K S, Nygaard Hans, Hasenkam J Michael, Johansen Peter
Division of Neurology, Department of Medicine and Therapeutics, Prince of Wales Hospital, Chinese University of Hong Kong, China.
J Neuroimaging. 2008 Oct;18(4):388-95. doi: 10.1111/j.1552-6569.2007.00211.x. Epub 2008 Nov 8.
Ischemic stroke is mainly caused by embolism. Vascular emboli can be solid or gaseous and can be non-invasively registered by transcranial Doppler ultrasound as microembolic signals (MESs). The existing methods are limited as they do not distinguish between cases in which a single embolus is present and those in which multiple emboli -- perhaps a mix of those gaseous and solid in nature -- are present. In a previous in vitro study, we have developed a wavelet-based algorithm to detect multiple emboli. We proceed with this technique to investigate whether it could prove useful in patients.
MESs were collected during emboli monitoring from patients undergoing carotid artery stenting and from patients having middle cerebral artery stenosis, and continuous wavelet transform was used to detect multiple emboli.
From 17 MESs recorded from middle cerebral artery stenosis patients, we found no multiple MES. From 306 MESs recorded from carotid stenting, we found 31 multiple MESs.
Multiple emboli were detected and quantified in patients using continuous wavelet transform. These were difficult to observe using conventional analysis techniques.
缺血性中风主要由栓塞引起。血管栓子可以是固体或气体，并且可以通过经颅多普勒超声作为微栓子信号（MESs）进行非侵入性记录。现有方法存在局限性，因为它们无法区分存在单个栓子的情况和存在多个栓子（可能是气态和固态混合的栓子）的情况。在先前的一项体外研究中，我们开发了一种基于小波的算法来检测多个栓子。我们采用这种技术来研究它是否对患者有用。
在对接受颈动脉支架置入术的患者和患有大脑中动脉狭窄的患者进行栓子监测期间收集MESs，并使用连续小波变换来检测多个栓子。
在大脑中动脉狭窄患者记录的17个MESs中，我们未发现多个MES。在颈动脉支架置入术记录的306个MESs中，我们发现了31个多个MES。
使用连续小波变换在患者中检测并量化了多个栓子。使用传统分析技术很难观察到这些栓子。
