经颅多普勒超声微栓子检测技术中分贝阈值的选择

目的　通过采用EMETC 2 0 2 0型PioneerVersion 2 .1检测系统对正常人大脑中动脉进行监测 ,以期获得帮助确定栓子信号分贝 (dB)阈值的参考数据。方法　正常人 50名按年龄分为 3组 (≤ 30岁 1 0名 ;>65岁 2 0名 ;30～ 65岁2 0名 ) ,选用相同技术参数监测大脑中动脉 30min。结果　 30min内总的信号数及不同dB值信号 (3～ 6dB)的频率之间 ,3组比较差异无显著性意义 ;30min内未出现 7dB值以上的信号 ;不同dB值信号的出现频率分别为 :3dB 87.0 7%(1 0 1 / 1min) ,4dB 1 1 .64 % (1 2 / 30min) ,5dB 1 .1 8% (1 / 30min) ,6dB 0 .1 0 % (0 .1 / 30min)。结论　采用EMETC 2 0 2 0型TCD仪作循环中微栓子检测时 ,栓子的信号阈值应≥ 5dB

Selection of decibel threshold for Detecting Doppler Embolic signals

Objective To improve reproducibility and reliability in the identification of embolic signals detected by Doppler ultrasound.Various thresholds between 3 and 12dB have been used,but different methods of measurement with different machines could result in different decibel intensity for the same embolic signal. Therefore, we examined 50 normal volunteers for 30 minutes using EME TC 2020 pioneer automatic embolus software in order to get information about what is a decibel threshold in detecting Doppler embolic signals. Methods Fifty normal volunteers were divided into 3 groups based on ages (10 cases ≤30 years, 20 cases >65 years and 20 cases 30～65 years).Recordings were made for middle cerebral artery for 30 minutes with the same parameters. Results Among the 3 groups, no significant differences were found in total episode numbers and proportional ratio of different intensity signals (3dB,4dB, 5dB, 6dB). During the 30 minute examination, no signal≥7dB was recorded. Frequencies of signals of different intensities were: 3dB 87.07% (101/1 minutes), 4dB 11.65%(12/30minutes), 5dB 1.18%(1/30 minutes), and 6dB 0.1%(0.1/30 minutes). Conclusion Using the EME TC 2020 Pioneer, the decibel threshold of Doppler embolic signals must be ≥5dB.