Background: Thyroid nodules are highly prevalent, affecting up to 75% of the population, yet most are benign. The limited specificity of ultrasound-based workup leads to substantial overdiagnosis and overtreatment, underscoring the need for improved imaging-based classification. Diffusion-weighted MRI (DWI), quantified via the apparent diffusion coefficient (ADC), has emerged as a promising imaging biomarker. This meta-analysis updates pooled diagnostic performance metrics and systematically evaluates which DWI acquisition techniques, imaging parameters, and combinations with other MRI modalities are most promising for clinical translation.Methods: PubMed, Web of Science, Scopus, and ProQuest were systematically searched. Pooled sensitivity, specificity, and area under the curve (AUC) were calculated using bivariate random-effects models. The effects of b-value, magnetic field strength, echo time, and diffusion model on diagnostic accuracy and ADC values were examined through subgroup and meta-regression analyses.Results: Forty-six studies (3003 nodules) were included. Pooled sensitivity and specificity were 0.84 (95% CI: 0.81–0.86) and 0.88 (95% CI: 0.85–0.90), with an AUC of 0.912. Intravoxel incoherent motion and diffusion kurtosis imaging showed no added value over the mono-exponential model. For the mono-exponential model, a negative association between b-values and reported ADCs was observed, whereas no association was found between b-values and diagnostic accuracy. Magnetic field strength and echo time did not affect ADCs. Combining DWI with morphological imaging showed the potential to further enhance diagnostic performance.Conclusions: DWI holds strong potential to improve the diagnostic workup of thyroid nodules. Technical standardization, particularly of key acquisition parameters, should be pursued to enable clinical implementation.
背景：甲状腺结节患病率极高，影响高达75%的人群，但大多数为良性病变。基于超声检查的特异性有限，导致显著的过度诊断与过度治疗，凸显了改进基于影像学分类方法的必要性。扩散加权磁共振成像（DWI）通过表观扩散系数（ADC）进行量化，已成为一种有前景的影像学生物标志物。本荟萃分析更新了汇总诊断效能指标，并系统评估了哪些DWI采集技术、成像参数以及与其他MRI模态的组合最具临床转化潜力。 方法：系统检索了PubMed、Web of Science、Scopus和ProQuest数据库。采用双变量随机效应模型计算汇总敏感性、特异性及曲线下面积（AUC）。通过亚组分析和荟萃回归，研究了b值、磁场强度、回波时间及扩散模型对诊断准确性和ADC值的影响。 结果：共纳入46项研究（3003个结节）。汇总敏感性为0.84（95% CI: 0.81–0.86），特异性为0.88（95% CI: 0.85–0.90），AUC为0.912。体素内不相干运动与扩散峰度成像相较于单指数模型未显示附加价值。对于单指数模型，观察到b值与报告ADC值呈负相关，而b值与诊断准确性无关联。磁场强度与回波时间不影响ADC值。DWI与形态学成像结合显示出进一步提升诊断效能的潜力。 结论：DWI在改善甲状腺结节诊断流程方面具有强大潜力。应推进技术标准化，特别是关键采集参数的标准化，以实现临床推广应用。
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