Uyama C, Kita Y, Matsusita S
Department of Investigative Radiology, National Cardiovascular Center, Osaka, Japan.
Invest Radiol. 1993 Dec;28(12):1128-33. doi: 10.1097/00004424-199312000-00008.
The authors studied the effects of image magnification and the type of edge detection filter on the precision of measuring blood vessel diameters on coronary angiograms.
A blood vessel phantom containing five channels of various diameters filled with contrast medium was filmed. The magnifications examined were x4, x10, and x20, and the edge detection filters used were the first derivative, second derivative, composite, and entropy filters. The regression line y = a+bx was introduced, where x represents the nominal diameter and y the diameter measured by the edge-detection filters. Determination criteria were the offset, slope, and residual variance from the regression equation.
The best value among three criteria was obtained with a magnification of x10 or x20. The entropy filter gave the best value of slope and residual variance. The composite filter gave the best value of offset.
The most precise measurement is obtained when the entropy filter and a magnification of x10 or x20 are applied.
作者研究了图像放大倍数和边缘检测滤波器类型对冠状动脉造影血管直径测量精度的影响。
拍摄一个装有五种不同直径通道且充满造影剂的血管模型。检查的放大倍数为x4、x10和x20，使用的边缘检测滤波器有一阶导数、二阶导数、复合和熵滤波器。引入回归线y = a + bx，其中x代表标称直径，y代表通过边缘检测滤波器测量的直径。判定标准是回归方程的偏移、斜率和残差方差。
在放大倍数为x10或x20时，三个标准中获得了最佳值。熵滤波器给出了最佳的斜率和残差方差值。复合滤波器给出了最佳的偏移值。
当应用熵滤波器和x10或x20的放大倍数时，可获得最精确的测量结果。
