脳血管撮影における微小栓子シグナル検出の意義

概要

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We evaluated the tendency for MES to appear during cerebral angiography (AG). The subjects were 89 patients (M/F=44/45, mean age=53 y). During AG, a transcranial Doppler (TCD) study was performed in two channels (proximal and distal MCA) by TC2020. The protocol for MES detection was a threshold level of 6 to 9 dB, and a saving time of 1 s. Micro-bubble was defined at more than 400 Hz, and solid embolus was less than 400 Hz for frequency analysis of MES. Within 10 days after AG, MRI was performed in 17/89cases (19%).Results: TCD studies were not possible in 11 women and 3 men, and there were 75 detectable cases. MES were detected in 62 of 75 cases. The numbers of MES in each AG were 5±4.4 on regular AG, 2±2.2 on test injection, and 2±0.7 during catheterization.Frequency analysis for MES showed that solid embolus was mostly observed during catheterization in 13% (8/62), and that micro-bubbles were detected during injection of contrast medium in 87% (54/62). Among the 17 MES-positive cases, two had ischemic lesions detected on MRI.It is concluded that use of a minimum necessary amount of contrast medium and careful handling of catheters are recommended in order to decrease the incidence of MES.