Forteza A M, Babikian V L, Hyde C, Winter M, Pochay V
Department of Neurology, University of Miami, FL, USA.
Stroke. 1996 Apr;27(4):687-90. doi: 10.1161/01.str.27.4.687.
High-intensity transient signals (HITS) detect ed by transcranial Doppler ultrasonography correspond to microemboli in intracranial arteries. The aim of this study was to determine the time course of cerebral microembolism in patients with symptomatic internal carotid artery stenosis and to assess its relation to specific symptoms of cerebral ischemia.
On the basis of criteria established a priori, 69 middle cerebral arteries were selected from a series of consecutive studies obtained at our neurovascular laboratory. All patients had radiological evidence of cervical internal carotid artery disease and had corresponding symptoms. A TC-2000 instrument equipped with special software for microembolus detection was used. Accepted signals were unidirectional from baseline, had a chirping sound, were 9 dB higher than the surrounding blood, and lasted 25 milliseconds or more.
HITS were identified in 20 of 69 (29%) arteries. The median interval between onset of symptoms and time of testing was 4 days for HITS-positive arteries and 12 days for those that were HITS negative (P=.0046). Fourteen of 32 (44%) arteries with transient ischemic attacks and 6 of 37 (16%) arteries with cerebral infarction were HITS positive (P=.012).
In patients with symptomatic carotid stenosis, HITS are detected more frequently when patients are tested soon after symptoms of cerebral ischemia. HITS are also more prevalent in the territories of arteries with transient ischemic attacks rather than cerebral infarction. These findings may have diagnostic and therapeutic implications.
经颅多普勒超声检测到的高强度瞬态信号（HITS）与颅内动脉微栓子相对应。本研究的目的是确定有症状的颈内动脉狭窄患者脑微栓塞的时间进程，并评估其与脑缺血特定症状的关系。
根据预先设定的标准，从我们神经血管实验室进行的一系列连续研究中选取69条大脑中动脉。所有患者均有颈内动脉疾病的影像学证据且有相应症状。使用配备有微栓子检测专用软件的TC - 2000仪器。可接受的信号应从基线开始为单向，有啁啾声，比周围血流高9分贝，且持续25毫秒或更长时间。
69条动脉中有20条（29%）检测到HITS。HITS阳性动脉症状发作与检测时间之间的中位间隔为4天，HITS阴性动脉为12天（P = 0.0046）。32条有短暂性脑缺血发作的动脉中有14条（44%）HITS阳性，37条有脑梗死的动脉中有6条（16%）HITS阳性（P = 0.012）。
在有症状的颈动脉狭窄患者中，脑缺血症状出现后不久进行检测时，HITS的检测频率更高。HITS在有短暂性脑缺血发作的动脉区域也比脑梗死区域更普遍。这些发现可能具有诊断和治疗意义。
