CT IMAGE DETAIL AND NOISE
CT IMAGE DETAIL AND NOISE
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DOI：
10.1148/radiographics.12.5.1529128
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发表时间：
1992-09-01
期刊：
影响因子：
5.5
通讯作者：
SPRAWLS, P
中科院分区：
文献类型：
--
作者：
SPRAWLS, P
计算机断层扫描 (CT) 图像影响解剖结构和病理特征可视化能力的两个重要特征是模糊和噪声。模糊程度的增加会降低小物体的可见度（图像细节）；视觉噪声的增加会降低低对比度物体的可见度。 CT 中的模糊源包括采样孔径的大小（可以通过焦斑大小和探测器大小来调节）、体素的大小以及所选的重建滤波器。噪声是由体素之间的衰减系数的变化引起的。使用小体素和边缘增强滤镜有助于减少模糊并提高精细细节的可见度。然而，小体素吸收较少的光子，因此导致噪声增加。可以通过使用大体素、增加辐射剂量或使用平滑滤波器来减少噪声，但该滤波器会增加模糊。针对特定临床研究的优化方案必须考虑这些物理原理并进行调整，以在细节、低噪音和患者暴露之间实现适当的平衡。
Two important characteristics of the computed tomographic (CT) image that affect the ability to visualize anatomic structures and pathologic features are blur and noise. Increased blurring reduces the visibility of small objects (image detail); increased visual noise reduces the visibility of low-contrast objects. Sources of blurring in CT include the size of the sampling aperture (which can be regulated by the focal spot size and the detector size), the size of the voxels, and the reconstruction filter selected. Noise is caused by the variation in attenuation coefficients between voxels. Use of small voxels and edge-enhancing filters helps reduce blurring and improve visibility of fine details. However, small voxels absorb fewer photons and therefore result in increased noise. Noise can be reduced by using large voxels, increasing radiation dose, or using a smoothing filter, but this filter increases blurring. An optimized protocol for a specific clinical study must take these physical principles into account and be adjusted to give proper balance among detail, low noise, and patient exposure.