Akiyama Y, Yoshimoto H, Nagatsuka K, Todaka T, Nomura M, Sawada M, Morimoto M, Hashimoto N
Department of Cerebrovascular Surgery, National Cardiovascular Center.
No Shinkei Geka. 1997 Aug;25(8):707-12.
Transcranial Doppler ultrasound (TCD) has been used to detect microemboli in cases with extracranial internal carotid artery stenosis. However, the mechanism causing microemboli has remained unclear. The purpose of this study is to clarify clinical characteristics and circumstances associated with the genesis of TCD-detected microemboli. Ninety-one cases with more than 30% stenosis of the internal carotid arteries were studied. TCD monitoring was carried out for an hour at the ipsilateral middle cerebral artery of each case using a 2-MHz pulse-wave transcranial Doppler device, and high intensity transient signals were counted as microemboli. Digital subtraction angiography, magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT) were also performed in all cases. Microemboli were detected in 30 of 91 cases. Microemboli were significantly well detected in cases with a history of ischemic event and/or cerebral infarction recognized by MRI. Detection of microemboli had no relation to sex, age or clinical risk factors (hypertension, hypercholesterolemia, diabetes mellitus and smoke habituation). In contrast, detection of microemboli was significantly related to decrease in cerebral blood flow recognized by SPECT, severity of stenosis and wall irregularity of lesion recognized by angiography. Microemboli can be found in a significantly high percentage of these clinical conditions, which may be risk factors for embolic stroke caused by extracranial internal carotid artery stenosis.
经颅多普勒超声（TCD）已被用于检测颅外颈内动脉狭窄病例中的微栓子。然而，导致微栓子的机制仍不清楚。本研究的目的是阐明与TCD检测到的微栓子形成相关的临床特征和情况。对91例颈内动脉狭窄超过30%的患者进行了研究。使用2兆赫脉冲波经颅多普勒设备对每个病例的同侧大脑中动脉进行1小时的TCD监测，并将高强度瞬态信号计为微栓子。所有病例均进行了数字减影血管造影、磁共振成像（MRI）和单光子发射计算机断层扫描（SPECT）。91例中有30例检测到微栓子。在有MRI证实的缺血事件和/或脑梗死病史的病例中，微栓子的检测效果明显更好。微栓子的检测与性别、年龄或临床危险因素（高血压、高胆固醇血症、糖尿病和吸烟习惯）无关。相比之下，微栓子的检测与SPECT证实的脑血流量减少、血管造影证实的狭窄严重程度和病变壁不规则显著相关。在这些临床情况下，微栓子的发现比例可能很高，这可能是颅外颈内动脉狭窄导致栓塞性中风的危险因素。
