On the Utility of Quantitative Diffusion-Weighted MR Imaging as a Tool in Differentiation between Malignant and Benign Thyroid Nodules

Rationale and Objectives To evaluate the ability of diffusion-weighted magnetic resonance imaging (DWI) in differentiating malignant thyroid nodules from benign lesions with a meta-analysis. Materials and Methods Articles in English and Chinese language relating to the accuracy of DWI for this utility were retrieved. Pooled estimation and subgroup analysis data were obtained by statistical analysis. Results A total of seven studies (17 subsets) with 358 patients, who fulfilled all of the inclusion criteria, were considered for the analysis. No publication bias was found (bias = 7.03, P  > .05). Methodological quality was relatively high. DWI sensitivity was 0.91 (95% confidence interval [CI], 0.87–0.94) and specificity was 0.93 (95% CI, 0.86–0.96). Overall, positive likelihood ratio was 12.24 (95% CI, 6.47–23.20) and negative likelihood ratio was 0.99 (95% CI, 0.06–0.15). Diagnostic odds ratio was 123.78 (95% CI, 56.85–269.48). The area under the curve of the summary receiver operating characteristic was 0.94 (95% CI, 0.92–0.96). In patients with high pretest probabilities, DWI enabled confirmation of malignant thyroid lesion; in patients with low pretest probabilities, DWI enabled exclusion of malignant thyroid lesion. Worst-case-scenario (pretest probability, 50%) posttest probabilities were 92% and 9% for positive and negative DWI results, respectively. Conclusions A limited number of small studies suggests that quantitative DWI is a reliable diagnostic method for differentiation between benign and malignant thyroid lesions.