小视野IVIM-DWI鉴别甲状腺良恶性结节的价值

目的 探讨小视野体素内不相干运动扩散加权成像（intravoxel incoherent motion diffusion-weighted imaging，IVIM-DWI）参数对甲状腺良恶性结节的鉴别诊断价值。方法  对48例（共75个结节）甲状腺结节患者行IVIM序列扫描，根据病理结果将75个结节分为良性组（56个结节）及恶性组（19个结节），比较两组双指数模型IVIM参数假扩散系数（Slow apparent diffusion coefficient，Slow ADC ）、真假扩散系数（Fast apparent diffusion coefficient，Fast ADC）、灌注分数（Fraction of fast ADC，f）和传统单指数模型参数标准表观扩散系数（Standard apparent diffusion coefficient，Standard ADC），并评价其诊断效能。结果 良性组Standard ADC、Slow ADC、Fast ADC、f值分别为（1.90±0.45）×10 ^-3 mm²/s、（1.63±0.06）×10^-3 mm²/s、（153.44±104.58）×10 ^-3 mm²/s和（20.95±9.04）%；恶性组分别为（1.15±0.21）×10 ^-3 mm²/s、（0.96±0.23）×10^-3 mm²/s、（172.25±106.97）×10^-3 mm²/s和（22.94±8.60）%，其中Standard ADC、Slow ADC值差异有统计学意义（P＜0.01），Fast ADC、f值差异无统计学意义（P＞0.05）。Standard ADC值ROC曲线下面积为0.961，敏感度为89.47%，特异度为100%；Slow ADC值ROC曲线下面积为0.936，敏感度为89.47%，特异度为96.43%，两者ROC曲线下面积比较差异无统计学意义（P＞0.05）。结论 小视野IVIM-DWI对甲状腺良恶性结节有鉴别诊断价值，Standard ADC及Slow ADC是鉴别诊断甲状腺良恶性结节较敏感的参数。

Modeling of reduced field-of-view intravoxel incoherent motion on diffusion-weighted images for differentiating benign from malignant thyroid nodules

Objective To assess the value of reduced field-of-view intravoxel incoherent motion（IVIM） diffusion-weighted imaging for differentiating benign from malignant thyroid nodules. Methods The IVIM technique was used to visualize 75 thyroid nodules in 48 patients and determine benign or malignant status. These findings were compared with pathology results. Standard，Slow and Fast ADC values as well as f values were compared for the two groups. Receiver operating characteristic（ROC） curves were generated to determine diagnostic thresholds. Results  Benign nodules showed significantly higher values than malignant nodules for Standard ADC（1.90±0.45 vs 1.15±0.21×10^-3 mm²/s） and for Slow ADC（1.63±0.06 vs 0.96±0.23×10^-3 mm²/s） and marginally（non-significantly） lower values for Fast ADC（153.44±104.58 vs 172.25±106.97×10^-3 mm²/s） and for f value（20.95±9.04 vs 22.94±8.60%）. The area under the ROC curve was for 0.961 for standard ADC，which showed a sensitivity of 89.47% and specificity of 100%. The corresponding area for Slow ADC was 0.936，sensitivity was 89.47% and specificity was 96.43%. Conclusion Reduced field-of-view IVIM diffusion-weighted imaging has diagnostic potential for differentiating benign and malignant thyroid nodules.