Title: Role of Sonoelastography in Differentiating Benign and Malignant Thyroid Nodules
Authors: Anandu Mohan, M.N. Brahmadathan, Paul V Puthussery
Introduction: Thyroid nodules are a common medical problem seen in about 8.5% of the population. It is of clinical importance to diagnose malignant nodules from benign which do not require surgery and decide which patient should proceed to biopsy. Ultra sound elastography is a noninvasive technique to evaluate the tissue stiffness of the lesion .The present study aims to assess the sensitivity, specificity, positive and negative predictive value of Strain Elastography in differentiating benign and malignant thyroid nodules by comparing with histo pathological analysis as the reference standard.
Materials and Methods: This study was a diagnostic test evaluation study involving 107 study subjects with palpable thyroid nodules who underwent ultrasound Strain elastography examination in Department of Radiodiagnosis for one year and six months.Strain elastography was performed and the nodules were classified into different elasticity scores according to the elasticity score developed by Itoh and Ueno. Scores 1,2&3 taken as benign and scores 4&5 were taken as malignant. Patients were followed up and their histopathological results after surgery were compared with the elastography findings. Sensitivity, specificity, positive predictive and negative predictive values were obtained. Also strain ratio was obtained for all lesions and a cut off value derived to aid in differentiating Malignant nodules from benign..
Results & Conclusion: Ultrasound strain elastography had a sensitivity of 90%, specificity of 94.3%, positive predictive value of 78.3% and negative predictive value of 97.6%.Strain ratio cut off of 3.96 derived which showed good diagnostic sensitivity, specificity and accuracy to differentiate malignant and benign nodules. Thus ultrasound Strain elastography scoring system and strain ratio found to be highly accurate in differentiating benign and malignant thyroid nodules.
Keywords:Thyroid; Thyroid nodules; Elastography; Strain Elastography; Strain ratio; Sonoelastography