Department of Radiology, Zhongshan Hospital, Fudan University and Shanghai Institute of Medical Imaging, Shanghai, 200030, China.
Department of Radiology, Affiliated Hospital of Qingdao University, Qingdao, 266000, Shandong, China.
Abdom Radiol (NY). 2018 Nov;43(11):3016-3024. doi: 10.1007/s00261-018-1573-5.
To evaluate the value of MR imaging features in stratifying Grade 2 (G2) pancreatic neuroendocrine tumors (PNETs) using the 5% cut-off value of the Ki-67 index as reference standards.
Between January 2010 and October 2016, 41 G2 PNET patients (One patient had 3 tumors) with preoperative MR imaging were included. Tumor grading was based on the revised 2016 World Health Organization classification of PNETs. MR imaging features included size, shape, consistency, T1-w and T2-w signal intensities, enhancement pattern, apparent diffusion coefficient (ADC) ratios (tumor/normal pancreatic parenchyma).
16 Ki-67 index < 5% tumors (SKIT, 37.2%) and 27 Ki-67 index ≥ 5% tumors (LKIT, 62.8%) of G2 were evaluated. The LKIT showed solid consistency (85% vs. 50%, P < 0.05), incomplete envelope-like reinforcement in a delayed phase (74% vs. 62%, P < 0.05), and liver or lymph node metastases (67% vs. 31%, P < 0.05) more frequently than did SKIT. However, ADC ratios of LKIT were smaller than SKIT (0.85 ± 0.23 vs. 1.29 ± 0.39, P = 0.001). Using binary logistic regression analysis, the ADC ratio was an independent significant differentiator of SKIT from LKIT. The AUROC of ADC ratios was 0.816 ± 0.07. The optimal cut-off value for the identification of LKIT was 1.25 × 10 (sensitivity 96.3%, specificity 62.5%).
MRI features may identify the overbroad scope of G2 PNETs and help predict Ki-67 values, as a surrogate for tumor aggressiveness, in G2 PNETs. An optimal cut-off value for predicting Ki-67 status (≥/< 5%) was 1.25 × 10 of ADC ratio.
使用 Ki-67 指数 5%的截断值作为参考标准，评估磁共振成像（MRI）特征在 2 级（G2）胰腺神经内分泌肿瘤（PNET）分级中的价值。
本研究纳入 2010 年 1 月至 2016 年 10 月间 41 例 G2 PNET 患者（1 例患者有 3 个肿瘤），术前均行 MRI 检查。肿瘤分级基于 2016 年世界卫生组织（WHO）PNET 分类的修订标准。MRI 特征包括肿瘤大小、形状、质地、T1 加权和 T2 加权信号强度、强化模式、表观扩散系数（ADC）比值（肿瘤/正常胰腺实质）。
本研究共评估了 16 例 Ki-67 指数＜5%的肿瘤（SKIT，37.2%）和 27 例 Ki-67 指数≥5%的肿瘤（LKIT，62.8%）。与 SKIT 相比，LKIT 更常表现为实性质地（85%比 50%，P＜0.05）、延迟期包膜样强化不完全（74%比 62%，P＜0.05）和肝或淋巴结转移（67%比 31%，P＜0.05）。然而，LKIT 的 ADC 比值小于 SKIT（0.85±0.23 比 1.29±0.39，P=0.001）。二元逻辑回归分析显示，ADC 比值是区分 SKIT 和 LKIT 的独立显著因素。ADC 比值的 AUC 为 0.816±0.07。用于识别 LKIT 的最佳截断值为 1.25×10，其对 LKIT 的识别敏感度为 96.3%，特异度为 62.5%。
MRI 特征可确定 G2 PNET 较广泛的范围，并有助于预测 Ki-67 值，Ki-67 值可作为 G2 PNET 侵袭性的替代标志物。预测 Ki-67 状态（≥/＜5%）的最佳截断值为 ADC 比值的 1.25×10。
