Mackinnon Andrew D, Aaslid Rune, Markus Hugh S
Department of Clinical Neurosciences, St. George's Hospital Medical School, Cranmer Terr, Tooting, London SW17 0RE, UK.
Stroke. 2004 Jan;35(1):73-8. doi: 10.1161/01.STR.0000106915.83041.0A. Epub 2003 Dec 18.
Transcranial Doppler (TCD) monitoring for asymptomatic cerebral emboli is currently limited to short recordings by equipment size, restricting its clinical usefulness. We have developed a first ambulatory TCD system, evaluated it in at-risk patient groups, and used it to study the pattern of embolization in patients with symptomatic carotid stenosis.
The system comprises an 18x11.5x3.2 cm battery-powered Doppler unit (425 g) and a 13-mm servo-controlled 2 MHz transducer probe. The quadrature raw Doppler signal is stored on flash-disk. An autosearch algorithm restores vessel insonation should signal quality fall. Initial evaluation was in 20 ambulatory stroke patients. Subsequently, 12 recently symptomatic carotid patients had recordings for > or =5 hours.
Recordings were well tolerated and a median of 96% of Doppler signal was suitable for analysis. Embolic signals were detected in 11 of the 12 symptomatic carotid patients. There was marked temporal variability in embolization and prolonging the recording increased the yield of embolic signal positive patients from 58% at 30 minutes to 92% at 150 minutes. In 3 subjects with frequent embolic signals, significant temporal clustering of embolic signals was observed.
We have developed the first ambulatory TCD system. Good-quality recordings of > or =5 hours can be obtained. In view of the demonstrated temporal variability in embolization, this technique is likely to improve the predictive value of recording for asymptomatic embolic signals and may be particularly useful in patients in whom embolic signals are relatively infrequent, such as those with asymptomatic carotid stenosis and atrial fibrillation.
经颅多普勒(TCD)对无症状脑栓塞的监测目前因设备尺寸限制,只能进行短时间记录,限制了其临床应用价值。我们研发了首个可移动TCD系统,在高危患者群体中进行了评估,并用于研究有症状颈动脉狭窄患者的栓塞模式。
该系统包括一个18×11.5×3.2厘米、由电池供电的多普勒单元(425克)和一个13毫米、伺服控制的2兆赫换能器探头。正交原始多普勒信号存储在闪存盘上。若信号质量下降,自动搜索算法可恢复血管探测。最初在20名可移动性卒中患者中进行了评估。随后,12名近期有症状的颈动脉患者进行了≥5小时的记录。
记录耐受性良好,中位数为96%的多普勒信号适合分析。12名有症状颈动脉患者中有11名检测到栓塞信号。栓塞存在明显的时间变异性,延长记录时间使栓塞信号阳性患者的检出率从30分钟时的58%提高到150分钟时的92%。在3名有频繁栓塞信号的受试者中,观察到栓塞信号有明显的时间聚集现象。
我们研发了首个可移动TCD系统。可获得≥5小时的高质量记录。鉴于已证实的栓塞时间变异性,该技术可能会提高无症状栓塞信号记录的预测价值,对于栓塞信号相对较少的患者,如无症状颈动脉狭窄和房颤患者可能特别有用。