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首页> 外文期刊>Journal of Clinical Ultrasound: JCU >Quantitative characterization of color Doppler images: reproducibility, accuracy, and limitations.
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Quantitative characterization of color Doppler images: reproducibility, accuracy, and limitations.

机译：彩色多普勒图像的定量表征：再现性，准确性和局限性。

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摘要

A computer-based quantitative analysis for color Doppler images of complex vascular formations is presented. The red-green-blue-signal from an Acuson XP10 is frame-grabbed and digitized. By matching each image pixel with the color bar, color pixels are identified and assigned to the corresponding flow velocity (color value). Data analysis consists of delineation of a region of interest and calculation of the relative number of color pixels in this region (color pixel density) as well as the mean color value. The mean color value was compared to flow velocities in a flow phantom. The thyroid and carotid artery in a volunteer were repeatedly examined by a single examiner to assess intra-observer variability. The thyroids in five healthy controls were examined by three experienced physicians to assess the extent of inter-observer variability and observer bias. The correlation between the mean color value and flow velocity ranged from 0.94 to 0.96 for a range of velocities determined by pulse repetition frequency. The average deviation of the mean color value from the flow velocity was 22% to 41%, depending on the selected pulse repetition frequency (range of deviations, -46% to +66%). Flow velocity was underestimated with inadequately low pulse repetition frequency, or inadequately high reject threshold. An overestimation occurred with inadequately high pulse repetition frequency. The highest intra-observer variability was 22% (relative standard deviation) for the color pixel density, and 9.1% for the mean color value. The inter-observer variation was approximately 30% for the color pixel density, and 20% for the mean color value. In conclusion, computer assisted image analysis permits an objective description of color Doppler images. However, the user must be aware that image acquisition under in vivo conditions as well as physical and instrumental factors may considerably influence the results.
机译：提出了基于计算机的复杂血管形成彩色多普勒图像的定量分析。 Acuson XP10的红绿蓝信号经过了帧抓取和数字化处理。通过将每个图像像素与颜色条进行匹配，可以识别颜色像素并将其分配给相应的流速（颜色值）。数据分析包括感兴趣区域的描绘和该区域中彩色像素的相对数量（彩色像素密度）以及平均颜色值的计算。将平均颜色值与流模型中的流速进行比较。由一名检查员反复检查志愿者的甲状腺和颈动脉，以评估观察者内部的变异性。由三位经验丰富的医师检查了五个健康对照组中的甲状腺，以评估观察者间差异和观察者偏倚的程度。对于由脉冲重复频率确定的一系列速度，平均色值与流速之间的相关性介于0.94至0.96之间。平均色值与流速的平均偏差为22％至41％，具体取决于所选的脉冲重复频率（偏差范围为-46％至+ 66％）。较低的脉冲重复频率或较高的剔除阈值会低估流速。脉冲重复频率过高时发生了高估。最高的观察者内部变异性是彩色像素密度的22％（相对标准偏差）和平均颜色值的9.1％。观察者之间的变化对于彩色像素密度大约为30％，对于平均颜色值大约为20％。总之，计算机辅助图像分析可以对彩色多普勒图像进行客观描述。但是，用户必须意识到，在体内条件下的图像采集以及物理和仪器因素可能会严重影响结果。

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