Efficacy of apparent diffusion coefficient in predicting aggressive histological features of papillary thyroid carcinoma

Özet

PURPOSE We aimed to evaluate preoperative diffusion-weighted magnetic resonance imaging (DWI) for predicting aggressive histological features in papillary thyroid cancer (PTC). METHODS This prospective study included 141 PTC patients, who underwent DWI prior to thyroidectomy; 88 patients with 88 PTC lesions were finally analyzed. Multiple comparisons of mean and minimum apparent diffusion coefficient (ADC) values ($ADC_{mean}$ and $ADC_{min}$) and ADC of the solid component ($ADC_{solid}$) between the lowly aggressive PTC, highly aggressive PTC without hobnail, and hobnail variant PTC groups were performed by one-way ANOVA or the Welch test. The nonparametric Kruskal-Wallis H test was used to assess lesion size differences. Receiver operating characteristic (ROC) curve analysis was also performed. RESULTS ADC values in the lowly aggressive PTC group were found to be significantly higher than those in the highly aggressive PTC without hobnail group ($ADC_{mean}$: 1.35±0.20×$10^{-3}$ $mm^2$ /s vs. 1.16±0.17×$10^{-3}$ $mm^2$ /s, P = 0.003; $ADC_{min}$: 1.10±0.17×$10^{-3}$ $mm^2$ /s vs. 0.88±0.16×$10^{-3}$ $mm^2$ /s, P 0.05). Lesion sizes in the hobnail variant PTC group was significantly elevated compared with the lowly aggressive PTC group (2.19±1.21 cm vs. 0.93±0.37 cm, P < 0.001). Areas under the curves (AUCs) for $ADC_{mean}$, $ADC_{min}$, and $ADC_{solid}$ between the lowly aggressive PTC and highly aggressive PTC group without hobnail were 0.758, 0.851, and 0.787, respectively. The AUC for size between the lowly aggressive and hobnail variant PTC group was 0.896. CONCLUSION $ADC_{min}$ from DWI could potentially provide quantitative information to differentiate lowly aggressive PTC from highly aggressive PTC lesions without hobnail variants.