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

1. Smallridge RC, Ain KB, Asa SL, Bible KC, Brierley JD, Burman KD, Kebebew E, Lee NY, Nikiforov YE, Rosenthal MS, Shah MH. American Thyroid Association guidelines for management of patients with anaplastic thyroid cancer. Thyroid. 2012 Nov 1;22(11):1104-39.
2. Unnikrishnan AG, Kalra S, Baruah M, Nair G, Nair V, Bantwal G, Sahay RK. Endocrine Society of India management guidelines for patients with thyroid nodules: A position statement. Indian journal of endocrinology and metabolism. 2011 Jan;15(1):2.
3. Usha MV, Sundaram KR, Unnikrishnan AG, Jayakumar RV, Nair V, Kumar H. High prevalence of undetected thyroid disorders in an iodine sufficient adult south Indian population. Journal of the Indian Medical Association. 2009 Feb;107(2):72-7.
4. Hegedüs L. The thyroid nodule. New England Journal of Medicine. 2004 Oct 21;351(17):1764-71.
5. Koike E, Noguchi S, Yamashita H, Murakami T, Ohshima A, Kawamoto H, Yamashita H. Ultrasonographic characteristics of thyroid nodules: prediction of malignancy. Archives of surgery. 2001 Mar 1;136(3):334-7.
6. Hong Y, Liu X, Li Z, Zhang X, Chen M, Luo Z. Real‐time ultrasound elastography in the differential diagnosis of benign and malignant thyroid nodules. Journal of Ultrasound in Medicine. 2009 Jul 1;28(7):861-7.
7. Mansor M, Okasha H, Esmat S, Hashem AM, Attia KA, Hussein HE. Role of ultrasound elastography in prediction of malignancy in thyroid nodules. Endocrine research. 2012 May 1;37(2):67-77.
8. Eltyib HE, Awad IA, Elsayed NM, Jastaniah SD. Real time ultrasound elastography for the differentiation of benign and malignant thyroid nodules. Open Journal of Medical Imaging. 2014 Mar 1;4(1):38.
9. Park SH, Kim SJ, Kim EK, Kim MJ, Son EJ, Kwak JY. Interobserver agreement in assessing the sonographic and elastographic features of malignant thyroid nodules. American Journal of Roentgenology. 2009 Nov;193(5):W416-23.
10. Itoh A, Ueno E, Tohno E, Kamma H, Takahashi H, Shiina T, Yamakawa M, Matsumura T. Breast disease: clinical application of US elastography for diagnosis. Radiology. 2006 May;239(2):341-50
11. Eltyib HE, Awad IA, Elsayed NM, Jastaniah SD. Real time ultrasound elastography for the differentiation of benign and malignant thyroid nodules. Open Journal of Medical Imaging. 2014 Mar 1;4(1):38
12. Rago T, Santini F, Scutari M, Pinchera A, Vitti P. Elastography: new developments in ultrasound for predicting malignancy in thyroid nodules. The Journal of Clinical Endocrinology & Metabolism. 2007 Aug 1;92(8):2917-22.
13. Wang H, Brylka D, Sun LN, Lin YQ, Sui GQ, Gao J. Comparison of strain ratio with elastography score system in differentiating malignant from benign thyroid nodules. Clinical imaging. 2013 Feb 28;37(1):50-5.
14. Xing P, Wu L, Zhang C, Li S, Liu C, Wu C. Differentiation of benign from malignant thyroid lesions. Journal of ultrasound in medicine. 2011 May 1;30(5):663-9.
15. Habib LA, Abdrabou AM, Geneidi EA, Sultan YM. Role of ultrasound elastography in assessment of indeterminate thyroid nodules. The Egyptian Journal of Radiology and Nuclear Medicine. 2016 Mar 31;47(1):141-7.

Dr M.N. Brahmadathan

Professor, Department of Radiodiagnosis, Government Medical College, Thrissur, India

Email: This email address is being protected from spambots. You need JavaScript enabled to view it.