Aizawa Mitsuhiro, Nishikawa Keiichi, Sasaki Keita, Kobayashi Norio, Yama Mitsuru, Sano Tsukasa, Murakami Shin-ichi
Department of Radiology, Suidobashi Hospital, Tokyo Dental College.
Nihon Hoshasen Gijutsu Gakkai Zasshi. 2012;68(1):30-9. doi: 10.6009/jjrt.2012_jsrt_68.1.30.
Development of multi-detector row computed tomography (MDCT) has enabled three-dimensions (3D) scanning with minute voxels. Minute voxels improve spatial resolution of CT images. At the same time, however, they increase image noise. Multi-planar reconstruction (MPR) is one of effective 3D-image processing techniques. The conventional MPR technique can adjust slice thickness of MPR images. When a thick slice is used, the image noise is decreased. In this case, however, spatial resolution is deteriorated. In order to deal with this trade-off problem, we have developed the weighted-averaging multi-planar reconstruction (W-MPR) technique to control the balance between the spatial resolution and noise. The weighted-average is determined by the Gaussian-type weighting function. In this study, we compared the performance of W-MPR with that of conventional simple-addition-averaging MPR. As a result, we could confirm that W-MPR can decrease the image noise without significant deterioration of spatial resolution. W-MPR can adjust freely the weight for each slice by changing the shape of the weighting function. Therefore, W-MPR can allow us to select a proper balance of spatial resolution and noise and at the same time produce suitable MPR images for observation of targeted anatomical structures.
多排探测器计算机断层扫描（MDCT）的发展使得能够进行具有微小体素的三维（3D）扫描。微小体素提高了CT图像的空间分辨率。然而，与此同时，它们增加了图像噪声。多平面重建（MPR）是一种有效的3D图像处理技术。传统的MPR技术可以调整MPR图像的切片厚度。当使用厚切片时，图像噪声会降低。然而，在这种情况下，空间分辨率会变差。为了解决这种权衡问题，我们开发了加权平均多平面重建（W-MPR）技术来控制空间分辨率和噪声之间的平衡。加权平均由高斯型加权函数确定。在本研究中，我们比较了W-MPR与传统简单加法平均MPR的性能。结果，我们可以确认W-MPR可以降低图像噪声，而不会显著降低空间分辨率。W-MPR可以通过改变加权函数的形状自由调整每个切片的权重。因此，W-MPR可以让我们选择空间分辨率和噪声的适当平衡，同时生成适合观察目标解剖结构的MPR图像。
