Brenner D E, Whitley N O, Houk T L, Aisner J, Wiernik P, Whitley J
JAMA. 1982 Mar 5;247(9):1299-302.
Modern computed tomographic (CT) scanners allow reasonably high-resolution cross-sectional visualization of most viscera and masses. To determine the accuracy of CT volume estimation, CT volumes of inanimate objects, cadaver kidneys and spleens, and in vivo balloons were performed. Regions of interest were outlined by a hand-operated cursor, and the computer program calculated the cross-sectional area in square millimeters and in pixels. A second computer program used Simpson's rule to calculate the volume from these multiple cross-sectional area. Calculated CT volumes were within +/-10% of directly measured volumes. Tumor masses being treated by chemotherapy were followed up clinically and by CT. Volume changes determined by CT are believed to be equal to and frequently more sensitive than clinical examination. From our experimental CT and clinical experiences, accuracy can be affected by (1) respiratory movement; (2) rapid changes in in vivo blood volume; (3) low CT number-gradient at the objects' periphery; (4) observer error in cursor tracing of the desired structure; and (5) mathematical errors inherent in Simpson's rule. We conclude that CT can estimate volumes of CT definable masses and can be useful in following tumor response to therapy.
现代计算机断层扫描（CT）扫描仪能够对大多数内脏器官和肿块进行具有相当高分辨率的横断面成像。为了确定CT体积估计的准确性，我们对无生命物体、尸体肾脏和脾脏以及活体球囊进行了CT体积测量。通过手动光标勾勒出感兴趣区域，计算机程序计算以平方毫米和像素为单位的横截面积。另一个计算机程序使用辛普森法则根据这些多个横截面积计算体积。计算得到的CT体积在直接测量体积的±10%范围内。对接受化疗的肿瘤肿块进行了临床随访和CT随访。据信，由CT确定的体积变化与临床检查结果相当，且通常更敏感。根据我们的CT实验和临床经验，准确性可能会受到以下因素影响：（1）呼吸运动；（2）体内血容量的快速变化；（3）物体周边CT值梯度较低；（4）观察者在勾勒所需结构时的光标追踪误差；以及（5）辛普森法则固有的数学误差。我们得出结论，CT能够估计CT可定义肿块的体积，并且在跟踪肿瘤对治疗的反应方面可能会很有用。
