Han Xu, Suo Shiteng, Sun Yawen, Zu Jinyan, Qu Jianxun, Zhou Yan, Chen Zengai, Xu Jianrong
Department of Radiology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, P.R. China.
GE Healthcare China, Shanghai, China.
J Magn Reson Imaging. 2017 Mar;45(3):722-730. doi: 10.1002/jmri.25405. Epub 2016 Aug 16.
To compare four methods of region-of-interest (ROI) placement for apparent diffusion coefficient (ADC) measurements in distinguishing low-grade gliomas (LGGs) from high-grade gliomas (HGGs).
Two independent readers measured ADC parameters using four ROI methods (single-slice [single-round, five-round and freehand] and whole-volume) on 43 patients (20 LGGs, 23 HGGs) who had undergone 3.0 Tesla diffusion-weighted imaging and time required for each method of ADC measurements was recorded. Intraclass correlation coefficients (ICCs) were used to assess interobserver variability of ADC measurements. Mean and minimum ADC values and time required were compared using paired Student's t-tests. All ADC parameters (mean/minimum ADC values of three single-slice methods, mean/minimum/standard deviation/skewness/kurtosis/the10 and 25 percentiles/median/maximum of whole-volume method) were correlated with tumor grade (low versus high) by unpaired Student's t-tests. Discriminative ability was determined by receiver operating characteristic curves.
All ADC measurements except minimum, skewness, and kurtosis of whole-volume ROI differed significantly between LGGs and HGGs (all P < 0.05). Mean ADC value of single-round ROI had the highest effect size (0.72) and the greatest areas under the curve (0.872). Three single-slice methods had good to excellent ICCs (0.67-0.89) and the whole-volume method fair to excellent ICCs (0.32-0.96). Minimum ADC values differed significantly between whole-volume and single-round ROI (P = 0.003) and, between whole-volume and five-round ROI (P = 0.001). The whole-volume method took significantly longer than all single-slice methods (all P < 0.001).
ADC measurements are influenced by ROI determination methods. Whole-volume histogram analysis did not yield better results than single-slice methods and took longer. Mean ADC value derived from single-round ROI is the most optimal parameter for differentiating LGGs from HGGs.
3 J. Magn. Reson. Imaging 2017;45:722-730.
比较四种感兴趣区（ROI）放置方法用于表观扩散系数（ADC）测量以区分低级别胶质瘤（LGG）与高级别胶质瘤（HGG）的效果。
两名独立阅片者对43例患者（20例LGG，23例HGG）采用四种ROI方法（单层面[单轮、五轮和徒手绘制]及全容积）测量ADC参数，这些患者均接受了3.0特斯拉扩散加权成像，并记录每种ADC测量方法所需时间。组内相关系数（ICC）用于评估ADC测量的观察者间变异性。采用配对t检验比较平均和最小ADC值及所需时间。所有ADC参数（三种单层面方法的平均/最小ADC值、全容积方法的平均/最小/标准差/偏度/峰度/第10和25百分位数/中位数/最大值）通过非配对t检验与肿瘤分级（低级别与高级别）进行相关性分析。通过受试者工作特征曲线确定鉴别能力。
除全容积ROI的最小值、偏度和峰度外，所有ADC测量值在LGG和HGG之间均有显著差异（均P < 0.05）。单轮ROI的平均ADC值效应量最高（0.72），曲线下面积最大（0.872）。三种单层面方法的ICC为良好至优秀（0.67 - 0.89），全容积方法的ICC为中等至优秀（0.32 - 0.96）。全容积与单轮ROI的最小ADC值有显著差异（P = 0.003），全容积与五轮ROI的最小ADC值也有显著差异（P = 0.001）。全容积方法所需时间显著长于所有单层面方法（均P < 0.001）。
ADC测量受ROI确定方法的影响。全容积直方图分析的结果并不优于单层面方法，且所需时间更长。单轮ROI得出的平均ADC值是区分LGG和HGG的最优化参数。
3 J. Magn. Reson. Imaging 2017;45:722 - 730。
