Nakamori N, Doi K, Sabeti V, MacMahon H
Kurt Rossmann Laboratories for Radiologic Image Research, Department of Radiology, University of Chicago, Illinois 60637.
Med Phys. 1990 May-Jun;17(3):342-50. doi: 10.1118/1.596513.
We are developing an automated method for determining a number of parameters related to the size and shape of the heart and of the lungs in chest radiographs. In order to obtain standard patterns of the cardiac shadow as "gold standards," four radiologists traced their best estimates of the entire contour of the heart, including the largely invisible inferior margin, on 11 radiographs. These contours were analyzed by Fourier transform, and the results were used as a guide to obtain a shift-variant cosine function which was applied to the prediction of the cardiac contour by fitting a limited number of detected heart boundary points. These points were obtained from analysis of edge gradients in two orthogonal directions. A simple observer study indicated that the contours of the heart shadows computed for 60 chest radiographs were generally acceptable to radiologists for estimation of the size and area of the projected heart. We also detected the rib cage and the edges of the diaphragm, which enabled us to determine the projected thoracic area. From these results, we calculated the cardiothoracic ratio and other parameters, such as the ratio of the projected heart area to the projected thoracic area.
我们正在开发一种自动方法，用于确定胸部X光片中与心脏和肺部大小及形状相关的多个参数。为了获得心脏阴影的标准模式作为“金标准”，四位放射科医生在11张X光片上描绘出他们对心脏整个轮廓的最佳估计，包括大部分不可见的下缘。通过傅里叶变换对这些轮廓进行分析，结果用作指导，以获得一个平移可变余弦函数，该函数通过拟合有限数量检测到的心脏边界点来应用于心脏轮廓的预测。这些点是通过对两个正交方向上的边缘梯度进行分析获得的。一项简单的观察者研究表明，为60张胸部X光片计算出的心脏阴影轮廓对于放射科医生估计投影心脏的大小和面积而言总体上是可接受的。我们还检测了肋骨和膈肌边缘，这使我们能够确定投影的胸部面积。根据这些结果，我们计算了心胸比率和其他参数，例如投影心脏面积与投影胸部面积的比率。
