Differential Diagnosis Of Thyroid Nodules' Malignancy: By Using Multiparametric Magnetic Resonance Imaging

Objective: To assess the efficacy of single and combining use multiple parameters of multiparametric non contrast-enhanced MRI(NCE-MRI),dynamic contrast-enhanced MRI(DCE-MRI)and conventional contrast-enhanced MRI(CE-MRI)in the evaluation of thyroid nodule malignancy.Materials and Methods: Eighty-five patients with single or multiple thyroid nodules were included in this study.All the patients were performed with NCE-MRI,diffusion weighted imaging(DWI)and CE-MRI.The thyroid nodules' margin,appearant diffusion coefficient(ADC)values,and time signal-intensity curve(TIC)values were measured after MRI scanning without and with contrast medium.All the nodules were surgically removed and underwent routine pathological examination.All data were analyzed and compared to pathological findings.Results: 144 thyroid nodules were histo-pathologically identified,83 were malignant and 61 were benign.The patients at the diagnosis of malignant thyroid nodules were younger than whom at the diagnosis of benign thyroid nodules.Malignant nodules also tended to be ill-defined on T2WI(MT2)and DCE-MR imaging(MDCE),with low specificity.The malignant thyroid nodules had smaller sizes,lower ADC(b-300s/mm2,b-500s/mm2,and 800s/mm2)values,lower signal intensity of pre-contrast(Ipre)and higher signal intensity increment ratio(IR)than the benign nodules.Forward/Wald of Logistic regression analysis of the combined multiple MRI parameters(b-500 ADC,MDCE and IR(%))showed a significant difference(P<0.0001),with a cutoff-value 0.6704,AUC 0.853,81.25% sensitivity,76.67% specificity,82.3% PPV and 75.4% NPV.The P value of b-500 ADC,DCE-180 and IR(%)in the combination was 0.026,0.002 and 0.009,respectively.Conclusion: In this study,combining three parameters from MRI using b-500 ADC,MDCE and IR(%)demonstrates a promising diagnostic method to differentiate malignant thyroid nodules from benign ones.