Malkun C, María E, Vargas A, Hurtado R, Rangel A
Arch Inst Cardiol Mex. 1987 Jan-Feb;57(1):31-4.
To measure cardiac volumes from the cineventriculographic silhouette, a calibration factor (fc) is needed to correct the X rays' distorsion and amplification. In the past, several methods have been described in order to obtain this fc, whose determination is often trouble-some, and time consuming, because of the necessity of planimetry, and calibration grid use. In this paper, we describe a method to calculate the fc: after RAO left ventriculography was obtained, a metalic sphere, whose diameter is well known, is filmed at the same incidence and distance of the left ventricle from the X ray tube and image intensifier. A good correlation was found when ventricular volumes estimated by the sphere, plannimetry of a grid, and ellipsoid axes measuring methods were compared (p less than 0.01). Methodology of the three procedures is being discussed and sphere method is recommended, because it avoids the grid use or planimetry performance and because it makes easier the fc determination.
为了从电影心室造影轮廓测量心脏容积，需要一个校准因子（fc）来校正X射线的畸变和放大。过去，已经描述了几种获得该fc的方法，由于需要进行平面测量和使用校准网格，其测定通常麻烦且耗时。在本文中，我们描述了一种计算fc的方法：在获得右前斜位左心室造影后，拍摄一个直径已知的金属球，其拍摄角度和距离与左心室到X射线管和影像增强器的相同。当比较通过球体估计的心室容积、网格的平面测量和椭圆轴测量方法时，发现了良好的相关性（p小于0.01）。正在讨论这三种方法的方法论，并推荐球体法，因为它避免了使用网格或进行平面测量，并且使fc的测定更容易。
