心原性脳塞栓症における微小栓子信号の検出 ＴＣＤによる微小栓子検出における問題点

Abstract

Cardiogenic embolism is one of the main causes of stroke. We analyzed the prevalence of microembolic signals (MES) in patients with recent cardiogenic embolism using a multigate technique. We examined 9 patients with cardiogenic embolism and 10 healthy controls, performing transcranial Doppler (TCD) monitoring from one middle cerebral artery using a 2-MHz probe of a multigated tanscranial pulsed Doppler system. The prevalence of MES was 22%. Most of the patients receiving antithrombotic therapy showed no MES. Two patients with acute stroke before initiation of therapy had no MES. In one of them, TCD detected no MES at 4 days after the onset of stroke, but another embolic stroke recurred only one day after TCD monitoring. All the healthy controls were free of MES. TCD was useful for confirming the stroke mechanism and for predicting individual prognosis in some patients. The prevalence of MES was not so high, and TCD did not always detect MES in patients with acute cardiogenic embolism. Recording for longer than 30 min, or on multiple occasions per patient will be necessary.