不同MR序列测量宫颈癌放疗靶区的一致性比较

目的比较不同MR序列测量宫颈癌放疗靶区的一致性。方法回顾性分析38例经病理学证实的宫颈癌患者MR资料,均行MRI平扫、增强和扩散加权成像检查。分别在轴位T2WI、T1WI增强扫描(T1+C)以及表观扩散系数(apparent diffusion coefficient,ADC)图上手动勾画肿瘤轮廓,通过面积求和法计算大体肿瘤体积(gross tumor volum,GTV),将不同序列测算的GTV分为T2WI组、T1+C组和ADC组。采用One-way ANOVA计算各组GTV的平均值,Bland-Atlman法计算各组GTV的95%一致性界限(95%limits of agreement,95%LoA)。结果 T2WI、T1+C和ADC组GTV平均值分别为(46.35±28.04)cm^3、(44.27±26.66)cm^3和(47.50±28.55)cm^3,组间差异无统计学意义(F=0.132,P=0.877)。BlandAtlman结果显示,T2WI组与T1+C组、T2WI组与ADC组以及T1+C组与ADC组的95%LoA分别为(-16.43～20.59)cm^3、(-19.01～25.47)cm^3和(-20.13～22.44)cm^3,不同组Bland-Atlman散点图比较均存在5.26%(2/38)位于95%LoA范围外,超出临床可替代范围。结论不同MR序列测量宫颈癌放疗靶区的一致性欠佳,尚不能相互取代,综合分析T2WI、T1+C以及ADC更有利于宫颈癌放疗靶区的准确勾画。

Consistency of different MR sequences in measuring radiotherapy target areas of cervical cancer

Objective To compare the consistency of different MR sequences in measuring the target area of radiotherapy for cervical cancer. Methods A retrospective analysis was made on the data of 38 patients with cervical cancer initially diagnosed by pathology（ⅡB or above）. Tumor contours were delineated manually on axial T2WI，T1WI enhanced scan（T1+C） and apparent diffusion coefficient （ADC），respectively. Gross tumor volume（GTV） was calculated by area summation method. The GTV obtained from different sequences were divided into T2WI group，T1+C group and ADC group. One-way ANOVA was used to calculate the average values of three groups of GTV and compare their differences. Bland-Atlman method was used to calculate 95% consistency limits（95% LoA） of three groups of GTVs，and the consistency of three groups of GTVs was compared. Results The mean value of GTV in T2WIgroup，T1+C group and ADC group were （46.35±28.04） cm³、（44.27±26.66） cm³ and （47.50±28.55） cm³，respectively. There was no significant difference in mean GTV among the three groups（F=0.132，P=0.877）. Bland-Atlman results showed that 95% LoA in T2WI group and T1+C group，T2WI group and ADC group，T1+C group and ADC group were（-16.43-20.59） cm³，（-19.01-25.47） cm³ and  （-20.13-22.44） cm³，respectively. Bland-Atlman scatter plots in different groups were 5.26%（2/38） out of the 95% LoA range，which was beyond the clinical alternative range. Conclusions The consistency of different MR sequence measurements of cervical cancer radiotherapy target areas is not good，and can not be replaced by each other. Comprehensive analysis of T2WI，T1+C and ADC is more conducive to the accurate delineation of cervical cancer radiotherapy target areas.