直肠癌不同表观扩散系数测量方法的一致性研究

Interobserver variability for different methods of tumor apparent diffusion coefficient measurement in rectal cancer

目的:比较直肠癌不同表观扩散系数(apparent diffusion coefficient,ADC)的测量方法,评价其对直肠癌ADC的影响。方法:回顾性收集37例直肠癌患者,术前行MRI包括扩散加权成像(diffusion weighted imaging,DWI)(b值为0、1 000s/mm2)检查。由2名阅片者采用3种方法独立测量肿瘤ADC:全肿瘤测量、最大层面测量、肿瘤实性成分测量。计算不同测量方法所得ADC的一致性。结果:2名阅片者之间全肿瘤测量ADC的一致性极好(组内相关系数为0.87),而最大层面和实性成分测量ADC的一致性一般(组内相关系数分别为0.56、0.58)。实性成分测量所得ADC低于全肿瘤测量(P<0.001)和最大层面测量(P<0.001),而全肿瘤测量和最大层面测量所得SD值高于实性成分测量(P<0.001、P=0.02)。结论:测量方法影响直肠癌ADC的大小和测量一致性,全肿瘤测量ADC的可重复性最优。

Objective： To evaluate the interobserver variability for different methods of tumor apparent diffusion coefficient （ADC） measurement in rectal cancer. Methods： A total of 37 patients with rectal cancer were analyzed retrospectively. They underwent MRI including diffusion weighted imaging （DWI） （b values： 0 and 1 000 s/mm2）. The mean ADC values were measured by two readers using three region of interest （ROI） protocols： whole-volume, single slice and small solid samples. The values of ADC and standard deviation （SD） and interobserver variability were compared. Results： Intraclass correlation coeffcient （ICC） for whole-volume measurement was excellent （0.87）, while for single slice and small solid sample measurements were moderate （ICC： 0.56 for single slice, 0.58 for small solid sample）. ADC values measured by small solid sample method were significantly lower than those by whole-volume （P〈0.001） and single slice （P〈0,001）. The SDs calculated by whole-volume and single slice methods were significantly larger than that by small solid sample method （P〈0.001 and P=-0.02, respectively）. Conclusion： ADC values and interoberver variabilitv are influenced bv different measurement methods. There Deatabilitv of whole-volume method is the best.