基于CT图像对游离胸腔积液简易定量方法

目的探讨基于CT图像客观测量和计算游离胸腔积液量的方法。方法纳入40例有游离胸腔积液的成年患者。采用Philips EBW 4.5.3.40140工作站处理图像,获得游离性游离胸腔积液数字模型,并自动获取游离胸腔积液的体积(V)。测量液面到胸腔壁的垂直最大距离a、液体宽度b以及游离胸腔积液垂直长度c。将游离胸腔积液V与a、b、c、a×c、a×b、a×b×c关联。采用SPSS 19.0统计分析软件进行回归分析,获得曲线拟合方程。结果对V选取9种函数进行回归计算,并选取相关值的最佳函数。a的3次方程较为理想(R2=0.847,P<0.005),其单值计算公式为:V=-195.672+36.150a-1.064a2+0.013a3;a×c符合度最高(R2=0.937,P<0.005),其关于游离胸腔积液V的最佳计算3次方程式为V=-139.325+0.126(a×c)-1.269(E-5)×(a×c)2+5.720(E-10)×(a×c)2。结论针对游离胸腔积液V计算,a和a×c的回归方程均能满足计算要求。使用a的回归方程测量单值,即可获得游离胸腔积液V。还可使用a×c回归公式得到更加准确的结果。使用相对计算公式可提高游离胸腔积液量的估计精度,减少时间,为临床计算游离胸腔积液提供了一个便捷的方法。

Straightforward method for quantifying pleural effusion volume from CT scans

Objective To explore a mathematical calculation based on CT to quantitative assessment of free pleural effusion volume. Methods Forty adult free pleural effusion patients were enrolled. The volume (V) of free pleural effusion was calculated by Philips EBW workstation. Planar measurements were made on CT scans such as liquid level to the chest distance (a), liquid length (c) and width (b). Individual planar measurements a, b, c, a×c, a×b, a×b×c were statistically calculated with the detected volume of pleural effusion by SPSS 19.0. A mathematical calculation of the expression measurement was created. Results Nine kinds of functions to calculate were used. (The equation about a was preferable R²=0.847, P<0.005), the regression equation of single value of a was V=-195.672+36.150a-1.064a²+0.013a³. The most accurate correlation between the volume and planar measurements was found in the a×c (R²=0.937, P<0.005). Conversion of the measurement to the appropriate volume was possible by regression equation V=-139.325+0.126(a×c)-1.269(E-5)×(a×c)²+5.720(E-10)×(a×c)². Conclusion Both a and a×c equations are enough for calculation pleural effusion volume. The pleural effusion volume with an equation can be obtained by a single value a, which can be also obtained by a×c. Devised a method of conversion of planar measurements on CT scan to the volume of free pleural effusion may be easily and effectively used in routine practice.