van der Weide R, Zuiderveld K J, Mali W P, Viergever M A
Image Sciences Institute, University Hospital Utrecht, The Netherlands.
IEEE Trans Med Imaging. 1998 Oct;17(5):831-41. doi: 10.1109/42.736054.
Coil embolization is a safe treatment for cerebral aneurysms only if the width of the neck in relation to the fundus of the aneurysm is small. Therefore, accurate visualization of the aneurysmal neck is required both in the diagnostic process and during the intervention. Conventional digital subtraction angiography (DSA) is still the preferred modality for the examination of cerebrovascular abnormalities like aneurysms, but it often does not provide the required morphological characteristics due to the suboptimal selection of projection angles and resulting overprojections of surrounding vasculature. This paper presents a method for performing a computer-assisted calculation of the optimal projection angles for DSA by post-processing computed tomographic angiography (CTA) volume data using ray-casting techniques and a combination of image processing algorithms. By means of phantom studies, retrospective simulations of angiograms, and in vivo applications of calculated optimal viewing angles, it is demonstrated that the proposed method results in better angiographic projections of the neck of saccular aneurysms with small neck-fundus ratio than those acquired at standard angles prescribed by clinical protocols.
只有当动脉瘤颈部与瘤底的宽度较小时，弹簧圈栓塞术才是治疗脑动脉瘤的一种安全方法。因此，在诊断过程和介入治疗期间都需要准确显示动脉瘤颈部。传统数字减影血管造影（DSA）仍是检查动脉瘤等脑血管异常的首选方式，但由于投影角度选择欠佳以及周围血管系统产生的重叠投影，它往往无法提供所需的形态特征。本文提出一种方法，通过使用光线投射技术和图像处理算法组合对计算机断层血管造影（CTA）容积数据进行后处理，来执行DSA最佳投影角度的计算机辅助计算。通过模型研究、血管造影回顾性模拟以及计算出的最佳视角在体内的应用，结果表明，与按照临床方案规定的标准角度获取的图像相比，所提出的方法能更好地显示囊状动脉瘤颈部的血管造影投影，这些动脉瘤的颈部与瘤底比率较小。
