Comparative Study of TI-RADS, Elasticity Score, Strain Ratio and Quantitative Diffusion MR Weighted Imaging in Characterization of Thyroid Nodules; Which Has the Best Diagnostic performance?

Background: Thyroid nodules are common disorder of the thyroid gland. Early and precise diagnosis of malignant thyroid nodules is fundamental for effective treatment. Objectives: The purpose of this study is comparative evaluation of the diagnostic performance of TI-RADS, elasticity score, strain ratio and quantitative diffusion-weighted MRI in characterization of malignant and benign thyroid nodules. Patients and methods: Our study is prospective. 59 patients with 59 thyroid nodules were enrolled in this study. Conventional ultrasound with TI-RADS categorization, ultrasound strain elastography (elasticity score and strain ratio) as well as diffusion-weighted MR imaging and ADC value were evaluated for all cases. Histopathology results were the standard reference. Results: TI-RADS score had (80 %) sensitivity, (89.8 %) specificity and (84.9 %) accuracy. Elasticity score using 4-points Asteria's criteria with cutoff value =3 had (70 %) sensitivity, (91.8 %) specificity and (80.9 %) accuracy. When a cutoff value of 1.65 was used for strain ratio; (90 %) sensitivity, (71.4 %) specificity and (91.8 %) diagnostic accuracy noted. When a cutoff value of 1.45 x10-3 was used for ADC value; (80 %) sensitivity, (95.9 %) specificity and overall accuracy (98%) noticed. Multiparametric analysis enhanced the overall accuracy of TI-RADS scoring with the best diagnostic performance was achieved in our study by combining diffusion ADC value to the TI-RADS scoring with sensitivity 100%, specificity 95.9% and accuracy 98%. Conclusions: Strain ratio and diffusion ADC value had higher diagnostic performance than US TIRADS scoring in characterizing thyroid nodules. The best diagnostic performance in our study was achieved by combining diffusion ADC value to the TI-RADS scoring with overall accuracy of about 98%.