相关实验视频
Updated: Jun 12, 2025

08:07
Ultrasound-based Pulse Wave Velocity Evaluation in Mice
Published on: February 14, 2017
13.5K
三个波形的平均值是否足以产生脉冲波多普勒阻抗测量的真正代表值?
Ana Elizabeth Gomes de Melo Tavares Ferreira1, Jennifer Alphonse1, Alec William Welsh2
1School of Clinical Medicine, Discipline of Women's Health, Faculty of Medicine, University of New South Wales, Royal Hospital for Women, Sydney, Australia.
Ultrasound in medicine & biology
|September 22, 2024
概括
平均多个脉冲波多普勒 (PWD) 波形对于准确的母胎多普勒评估至关重要. 阻力指数 (RI) 显示出比脉动性指数 (PI) 更大的稳定性,需要更少的波形才能获得可靠的结果.
科学领域:
- 产科和妇科 产科和妇科
- 医疗成像医学成像
- 胎儿生理学 胎儿生理学
背景情况:
- 脉冲波多普勒 (PWD) 指数对于评估母胎健康至关重要.
- 在PWD波形测量的变化会影响诊断的准确性.
- 确定最佳波形平均值对于可靠的多普勒评估至关重要.
研究的目的:
- 为了评估常见的PWD阻抗指数的生理变化.
- 确定所需的波形的最小数量,以达到5%的变化率.
- 在母胎多普勒评估中,比较脉动性指数 (PI) 和抗性指数 (RI) 的变化.
主要方法:
- 这是一项前性,横截面的队列研究,涉及189例无并发症单子妊娠 (妊娠20-37周).
- 从动脉 (UA),中脑动脉 (MCA) 和子宫动脉 (UtAs) 获取100个PWD波形,从静脉管道 (ductus venosus) 获取30个.
- 使用变化系数评估波形变化,并通过移动平均和平均标准误差计算所需的平均值.
主要成果:
- 脉动性指数 (PI) 在所有研究的血管中表现出比阻力指数 (RI) 更大的变化.
- 至少需要14个UA/MCA和13个UtA的PWD波形,才能将PI变化率降低到5%.
- 只有2个UA,1个MCA和8个UtA RI波形才需要达到类似的变化.
结论:
- 由于观察到的变异性,PWD指数结果需要谨慎解释和对多个波形进行平均.
- 抵抗指数 (RI) 与母胎多普勒脉动指数 (PI) 相比显示出更高的稳定性.
- 建议采用RI进行母胎多普勒评估,以提高可靠性.
相关概念视频
Equipments Used To Measure Blood Pressure
839
Direct Method
This invasive approach involves cannulating a peripheral artery. During each cardiac contraction, pressure generates mechanical motion within the catheter, transmitted through rigid, fluid-filled tubing to a transducer. This transducer converts mechanical motion into electrical signals displayed as waveforms on a monitor. An automatic flushing system prevents blood backflow. Due to the potential risk of unexpected arterial blood loss, this method is primarily used in intensive...
This invasive approach involves cannulating a peripheral artery. During each cardiac contraction, pressure generates mechanical motion within the catheter, transmitted through rigid, fluid-filled tubing to a transducer. This transducer converts mechanical motion into electrical signals displayed as waveforms on a monitor. An automatic flushing system prevents blood backflow. Due to the potential risk of unexpected arterial blood loss, this method is primarily used in intensive...
839
Assessing Blood pressure using a doppler ultrasound
1.2K
To obtain accurate blood pressure measurements in clinical settings, especially when traditional methods are insufficient, healthcare professionals utilize the Doppler ultrasound technique. This method uses high-frequency sound waves to detect blood flow within the arteries, which is crucial for patients with conditions that complicate circulatory system assessment.
Pre-Procedural Guidelines for Doppler Ultrasound Blood Pressure Assessment:
Preparation of Equipment:
Pre-Procedural Guidelines for Doppler Ultrasound Blood Pressure Assessment:
Preparation of Equipment:
1.2K
RMS Value in AC Circuit
1.8K
The root mean square (RMS) value is a measure of the effective or average value of an alternating current (AC) waveform. In AC circuits, the voltage or current waveform constantly changes direction and magnitude, making it difficult to describe with a single value. The RMS value provides a convenient way to calculate the equivalent DC voltage or current that would produce the same heating effect in a resistor as the AC waveform.
Mathematically, the RMS value of an AC waveform is the square root...
Mathematically, the RMS value of an AC waveform is the square root...
1.8K
Average Power
581
In practical electrical applications, the concept of time-varying instantaneous power is not frequently utilized. Instead, focus shifts to the more practical quantity known as average power. Average power is determined by integrating the instantaneous power over a specified time period and subsequently dividing it by that duration.
581
Bode Plots Construction
672
The Bode plot is an essential tool in control system analysis, mapping the frequency response of a system through a magnitude plot and a phase plot, both against a logarithmic frequency axis. To construct a Bode plot, consider the transfer function H(ω):
672
Special considerations while measuring pulse
576
Assessing a patient's pulse is a fundamental skill in healthcare, but certain situations require special attention:
576

