The application of quantitative analysis of eADC values in differentiating benign from malignant thyroid nodules / 实用放射学杂志

ABSTRACT

Objective To evaluate the application of exponential apparent diffusion coefficient (eADC)value in differentiating benign from malignant thyroid nodules.Methods Routine MR sequences and axial diffusion weighted imaging (DWI)sequences with different b-values(0, 300,500,800 s/mm2)were performed in 46 patients with 51 histopathologically confirmed thyroid nodules,including 35 malignant nodules and 1 6 benign nodules.The eADC values of each thyroid nodules’solid component with different b-values were measured and assessed by independent samples t test.Receiver operating characteristic (ROC)curves were drawn and used to determine the diagnostic threshold and assess the screen test.Results The eADC values of the malignant nodules were higher than that of benign nodules (P<0.05)in all of the three different b-values.The eADC values of the malignant nodules and the benign nodules were 0.618±0.080 and 0.492±0.071 (b=300 s/mm2),0.520±0.104 and 0.371±0.077 (b=500 s/mm2)and 0.407±0.114 and 0.286±0.097 (b=800 s/mm2)respectively. According to the ROC curve,the area under the curve(AUC)was 0.883,0.890 and 0.824 when the b-value was set as 300,500 and 800 s/mm2respectively.When the b-value was set as 500 s/mm2and the diagnostic threshold was 0.454,the sensitivity,specificity, positive predictive value,negative predictive value and Youden index were 74.3%,93.8%,96.3%,60.9% and 0.68,respectively.Conclusion The eADC value is helpful in differentiating benign from malignant thyroid nodules,and the best result can be obtained by using DWI with b-value of 500 s/mm2.