多模态MR图像测量鼻咽癌GTV一致性评价

摘要

Objective To investigate the consistency of multiple magnetic resonance imaging ( MRI) modalities in measurement of gross tumor volume ( GTV) for nasopharyngeal carcinoma. Methods A retrospective analysis was performed among 45 patients who were newly diagnosed and pathologically confirmed with nasopharyngeal carcinoma. All patients underwent plain, enhanced, and diffusion-weighted MRI scans. Primary tumor was manually delineated on enhanced axial T1 WI, axial T2 WI, and apparent diffusion coefficient ( ADC) maps. GTV was calculated by the sum of areas. The obtained GTV was divided into T1+C group, T2 WI group, and ADC group. One-way analysis of variance was used to evaluate the differences between the mean values from the three groups. The Bland-Altman method was used to evaluate the consistency of different imaging modalities in GTV measurement using the mean difference between the two groups and 95% distribution of the difference. Results There was no significant difference in mean GTV between the T1+C group, the T2WI group, and the ADC group (20.8±18. 1) vs. (21.5±17. 2) vs. (24.4± 20. 8) cm3( P=0. 617) . The mean differences and 95% limits of agreement between the T2 WI group and the T1+C group, between the ADC group and the T2 WI group, and between the ADC group and the T1+C group were 0. 74, 2. 94, and 3. 68 cm3 and (-5. 97-7. 44 ) , (-8. 25-13. 69 ) , and (-3. 34-10. 70 ) cm3 , respectively. Conclusions The multiple MRI modalities have poor consistency in measurement of GTV for nasopharyngeal carcinoma. Therefore, they cannot replace each other. Enhanced T1 WI combined with T2 WI and DWMRI can determine a relatively accurate range of target volume for nasopharyngeal carcinoma.%目的 探讨多模态MR图像测量鼻咽癌GTV的一致性.方法 回顾分析45例经病理证实的鼻咽癌初诊病例,均行MRI平扫、增强和扩散加权成像检查.在轴位增强T1 WI、轴位T2 WI、ADC图像上手动勾画原发肿瘤轮廓,通过面积求和法计算GTV,将不同图像测量的GTV分成T1+C、T2 WI组和ADC组.采用单因素方差分析3个组平均值,Bland-Altman法通过两组差值平均值和95%分布范围评价不同模态图像测量GTV结果的一致性.结果 T1+C、T2WI、ADC组GTV分别为(20.8±18.1)、(21.5±17.2)、(24.4±20.8)cm3(P=0.617).T2WI和T1+C组、ADC和T2WI组、ADC和T1+C组差值的平均值和95%一致性界限分别为0.74(-5.97~7.44)、2.94(-8.25~13.69)、3.68(-3.34~10.70)cm3.结论 多模态MR图像测量鼻咽癌GTV一致性不佳,尚不能相互替代,增强T1 WI联合T2 WI、DWMRI可更准确地判断鼻咽癌靶区范围.