通过外切法计算的CT体积与长轴椭球体体积（二维测量值乘以冠状长轴）的准确性比较。

Comparison of the accuracy of CT volume calculated by circumscription to prolate ellipsoid volume (bidimensional measurement multiplied by coronal long axis).

作者信息

Rkein Ali M, Harrigal Chivonne, Friedman Arnold C, Persky Daniel, Krupinski Elizabeth

机构信息

Departments of Radiology, University of Arizona College of Medicine, Tucson, AZ 85724-5067, USA.

出版信息

Acad Radiol. 2009 Feb;16(2):181-6. doi: 10.1016/j.acra.2008.08.013.

DOI:10.1016/j.acra.2008.08.013

PMID:19124103

Abstract

RATIONALE AND OBJECTIVES

Tumor volume is one of the most important factors in evaluating the response to treatment of patients with cancer. The objective of this study was to compare computed tomographic (CT) volume calculation using a semiautomated circumscribing tracing tool (manual circumscription [MC]) to prolate ellipsoid volume calculation (PEVC; bidimensional measurement multiplied by coronal long axis) and determine which was more accurate and consistent.

MATERIALS AND METHODS

The study included six patients with nine neoplasms, six phantoms, and two radiologists. The neoplasms and phantoms of varying sizes and shapes were imaged using multidetector CT scanners, with slice thicknesses ranging from 0.5 to 3 mm. Measurements were performed using a TeraRecon 3D workstation. Each lesion and phantom was manually circumscribed, and its three dimensions were measured. The measurements were repeated 2 weeks later.

RESULTS

MC of the phantoms deviated from their true volumes by an average of 3.0 +/- 1%, whereas PEVC deviated by 10.1 +/- 3.99%. MC interobserver readings varied by 1.2 +/- 0.6% and PEVC by 4.8 +/- 3.3%. MC intraobserver readings varied by 1.95 +/- 1.75% and PEVC by 2.5 +/- 1.55%. Patient tumor volume predicted by MC and PEVC varied greatly; MC interobserver readings differed by 3.3 +/- 2.1% and PEVC by 20.1 +/- 10.6%. MC intraobserver readings varied by 2.5 +/- 1.9% and PEVC by 5.5 +/- 3.2%. Variability was greater for complex shapes than for simple shapes. Bidimensional analysis demonstrated an interobserver difference of 12.1 +/- 8.7% and an intraobserver difference of 5.05 +/- 3.3%. These results demonstrate large interobserver and intraobserver variability. Variability was greater for complex shapes than for simple shapes.

CONCLUSION

MC of neoplasms provided more accurate and consistent volume predictions than PEVC. More complicated shapes demonstrated the superiority of MC over PEVC.

摘要

原理与目的

肿瘤体积是评估癌症患者治疗反应的最重要因素之一。本研究的目的是比较使用半自动外接追踪工具（手动外接[MC]）计算的计算机断层扫描（CT）体积与长椭球体体积计算（PEVC；二维测量值乘以冠状长轴），并确定哪种方法更准确、更一致。

材料与方法

该研究纳入了6例患有9个肿瘤的患者、6个模型以及2名放射科医生。使用多排CT扫描仪对大小和形状各异的肿瘤及模型进行成像，层厚范围为0.5至3毫米。测量使用TeraRecon 3D工作站进行。对每个病变和模型进行手动外接，并测量其三维尺寸。2周后重复测量。

结果

模型的MC与真实体积的平均偏差为3.0±1%，而PEVC的偏差为10.1±3.99%。观察者间MC读数的差异为1.2±0.6%，PEVC为4.8±3.3%。观察者内MC读数的差异为1.95±1.75%，PEVC为2.5±1.55%。MC和PEVC预测的患者肿瘤体积差异很大；观察者间MC读数的差异为3.3±2.1%，PEVC为20.1±10.6%。观察者内MC读数的差异为2.5±1.9%，PEVC为5.5±3.2%。复杂形状的变异性大于简单形状。二维分析显示观察者间差异为12.1±8.7%，观察者内差异为5.05±3.3%。这些结果表明观察者间和观察者内存在较大变异性。复杂形状的变异性大于简单形状。