Boone J M, Corrigan N M, Hecht S T, Link D P
Department of Radiology, University of California, UC Davis Medical Center, Sacramento, USA.
J Digit Imaging. 1998 Nov;11(4):159-67. doi: 10.1007/BF03178078.
Digital subtraction angiography has been accepted as an invaluable clinical tool over the past decade; however, film-screen-based angiography is still performed routinely when high-resolution or large field-of-view angiograms are needed. A technique is presented whereby two films from an angiographic sequence are digitized using a high-resolution laser digitizer, and the digitized images are aligned, subtracted, and displayed using the computer. To accommodate for some types of patient motion, an image warping algorithm is presented and discussed in detail. The warping algorithm is piecewise linear, using triangular regions for warping, resulting in a global nonlinear transform across triangle elements. An algorithm describing optimal triangle selection also is discussed. The results show that subtraction images of excellent quality can be produced by the proposed technique, and suggest that, in some settings, digitized subtraction films may be preferred over conventional film subtraction.
在过去十年中，数字减影血管造影已被公认为一种极其重要的临床工具；然而，当需要高分辨率或大视野血管造影时，基于胶片屏的血管造影仍在常规进行。本文介绍了一种技术，即使用高分辨率激光数字化仪对血管造影序列中的两张胶片进行数字化处理，并利用计算机对数字化图像进行对齐、相减和显示。为了适应某些类型的患者运动，提出并详细讨论了一种图像变形算法。该变形算法是分段线性的，使用三角形区域进行变形，从而在三角形元素上产生全局非线性变换。还讨论了一种描述最佳三角形选择的算法。结果表明，所提出的技术可以产生高质量的减影图像，并表明在某些情况下，数字化减影胶片可能比传统的胶片减影更受青睐。
