Helical CT image noise--analytical results.
Helical CT image noise--analytical results.
复制标题
螺旋CT图像噪声——分析结果。
DOI：
10.1118/1.596950
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发表时间：
1993
期刊：
影响因子：
3.8
通讯作者：
M. Vannier
中科院分区：
文献类型：
--
作者：
G. Wang;M. Vannier
螺旋CT是X射线CT的一个重要的最新发展。在螺旋CT中，平面投影集通过插值从原始投影数据合成。在各种插值方案中，线性插值由于其效率和性能而通常是优选的。本文推导了典型螺旋CT线性插值方法的图像噪声方差，包括全扫描（FS）、欠扫描（US）、全扫描加插值（FI）、半扫描（HS）、半扫描加插值（HI）和半扫描加外推（HE）方法。将螺旋CT与常规360度重建（CR）的图像噪声偏差比制成表格。这与以前报道的模拟结果是一致的。理论结果为进一步理解螺旋CT的噪声性能提供了依据。结果表明，螺旋CT图像的噪声偏差是独立的横轴位置，成比例的原始投影噪声偏差，并不受扇形角（近似为HE方法）。此外，螺旋CT图像噪声方差与重建滤波器平方下的面积成比例。
Helical CT is an important recent development in x-ray CT. In helical CT, planar projection sets are synthesized from raw projection data via interpolation. Among various interpolation schemes, linear interpolation is usually preferred due to its efficiency and performance. In this paper, image noise variance is derived for typical helical CT linear interpolation techniques, including the full scan (FS), under-scan (US), full scan with interpolation (FI), half-scan (HS), half-scan with interpolation (HI) and half-scan with extrapolation (HE) methods. Image noise deviation ratios of helical CT to conventional 360 degrees reconstruction (CR) are tabulated. These are consistent with previously reported simulation results. The theoretical results provide further understanding of helical CT noise performance. It is shown that helical CT image noise deviation is independent of transaxial position, proportional to the raw projection noise deviation, and not affected by the fan angle (approximately for the HE method). Also, helical CT image noise variance is proportional to the area under the square of the reconstruction filter.