Diagnostic accuracy of diffusion weighted imaging in differentiating benign and malignant thyroid nodules: a cross sectional study

Aim: To evaluate the role of diffusion weighted MRI in differentiating benign from malignant thyroid nodules and correlating them with fine needle aspiration cytology (FNAC)/Histopathological examination.”
Materials and Methods: The study was conducted after getting approval from our institution ethical committee and after obtaining written informed consent from the patients in the Department of Radiology, SRM Medical College hospital and Research center, Kattankulathur, Chengalpattu district. It is a cross sectional study done on fifty patients who were diagnosed to have thyroid nodules by B-mode ultrasound or by palpation or incidental detection. Patients who refused to undergo FNAC, purely cystic nodules were excluded from the study. MRI was done using SIEMENS 1.5T essenza using b-values of 50, 500, 800 and apparent diffusion coefficient (ADC) maps were generated.
Results: Among the 50 cases, MRI ADC value had a sensitivity of 87.5%, specificity of 88% and an accuracy of 88% in differentiating benign and malignant thyroid nodules. The cut off ADC value for differentiating benign from malignant thyroid nodules was 0.859.
Conclusion: ADC values can help in differentiating benign and malignant thyroid nodules with better accuracy and specificity. This study lead us to believe that the incorporation of ADC values in MRI could avoid surgery in patients with thyroid nodules and comorbidities for whom potential risk of surgery outweighs the survival benefit.