感兴趣区大小及位置对肝DWI表观弥散系数测量值及可重复性影响  

Effect of region of interest on the apparent diffusion coefficient measurement and its reproducibility in liver MR diffusion-weighted imaging

作　　者：陈鑫[1,2] 梁长虹[2] 潘丹[1,2] 李晓丹[2] 颜丽芬[2] 曾珍[3] 刘再毅[2] 

机构地区：[1]南方医科大学,广东广州510515 [2]广东省人民医院广东省医学科学院医学影像部放射科 [3]解放军第302医院肝脏肿瘤诊疗研究中心

出　　处：《实用放射学杂志》2013年第8期1262-1265,1273,共5页Journal of Practical Radiology

基　　金：国家自然科学基金项目（81271569.81271654）;广州市科技支撑项目（2010J-E481）.

摘　　要：目的研究感兴趣区（region of interest，ROD大小及位置对DWI表观弥散系数（apparent diffusioncoefficient，ADC）测量值及其可重复性的影响。方法使用1．5T磁共振对36例正常志愿者进行2次肝DWI扫描。在3个连续层面的ADC图上．每个层面的左、有肝分别画2个大小相同的ROIs（ROI面积分别为50、100、200mm2和300mm2均照此方法测量ADC值）。用方差分析比较各种大小ROI所得ADC值的大小；左、右肝的ADC值比较用配对f检验；观察者自身及观察者间的一致性评价、ROI2次测量的可重复性评价用Bland-AltmM方法。结果当ROI大小相同时，左肝的ADC值较有肝高（P〈0．05），同时左肝的ADC值的可重复性较有肝差，右肝Bland-Altman结果（95％可信区间的范围）：8．1％～9．8％；左肝：11．3％～16．5％。无论是左肝还是右肝，不同大小ROI所得肝ADc值无统计学差异（P：0．164～0．452），且其重复性亦大致相同。结论ROI位置影响肝ADC值的大小及可重复性，而其大小并不影响ADC值大小及可重复性。位于左肝的ROI所得ADC值较右肝高且重复性差．测量ADC值时ROI尽量置于有肝．ROI为50mm2即可满足临床诊断。Objective To investigate the effect of the location and size of region of interest （ROI） on the ADC measurement and its reproducibility in liver MR diffusion-weighted imaging（DWI）. Methods Thirty-six healthy volunteers underwent liver DWI examination two times on a 1.5 Tesla MR scanner. Two ROIs with the same size were drawn on three consecutive middle slices on the right and left liver respectively on ADC maps（ADCs of different ROI sizes of 50,100,200 and 300 mm2 measured using the same method）. ANOVA analysis was used to compare the differences of the ADC values（ADCs） of both the left and right lobe obtained with different ROI sizes, the ADC values between the left and right lobe of the liver were compared by using the paired-sample t- test. The Bland-Ahman method was used to assess the reproducibility of the ADC measurement of inter- and intra-observer agreement, as well as the reproducibility with different ROI sizes. Results ADCs of left liver lobe were larger than those of right lobe and the reproducibility of ADCs of left lobe was worse than that of right lobe（Bland-Airman analysis for right liver： 8. 1%-9.8%; left liver lobe： 11.3%-16.5%）,when the same ROI size was selected （P〈0.05）. TheADCs with different ROI sizes were no significant statistically different（P：0. 164--0. 452）. And the reproducibilitiesof ADCs with different ROI sizes were similar in both right lobe and left lobe. Conclusion The ROI location influenced the ADCs measurement and its reproducibility, while the ROI size do not affect those. The ADCs calculated by ROIs with the same size in left lobe is higher and less producible than that of right liver. Therefore, we recommend to use ADCs of rigbt lobe to evaluate diffuse liver disease （such as liver cirrhosis） and ROIs of 50mm2 are enough for the clinical diagnosis.

关 键 词：肝脏 磁共振成像 扩散加权成像 表观弥散系数 可重复性 

分 类 号：R322.47[医药卫生—人体解剖和组织胚胎学] R445.2[医药卫生—基础医学]