Strain Elastography for Differentiation between Benign and Malignant Thyroid Nodules.

Objective: To find out the diagnostic accuracy of strain elastography in differentiating between benign and malignant thyroid nodules taking cytology as a gold standard.

Study Design: Descriptive study.

Place And Duration Of Study: Radiology Department, Institute of Nuclear Medicine and Oncology (INMOL), Lahore, Pakistan, from February to July 2019.

Methodology: A total of 110 patients aged 18-80 years of either gender having one or more solid nodules, in thyroid lobe on conventional ultrasound examination, were included. Patients with cystic nodules, nodules that constitute more than 75% volume of thyroid lobe and thyroid nodules with peripheral calcification were excluded. All the patients then underwent strain ultrasound elastography with high-resolution unit equipped with a linear array probe which was centered at 7.5 MHz. Sonoelastographic findings were correlated with cytology.

Results: Overall sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of sonoelastography in differentiating between benign and malignant thyroid nodules taking cytology as gold standard was 90.0%, 90.0%, 91.53%, 88.24% and 90.0%, respectively. Optimal cutoff to differentiate between malignant and benign nodules for elasticity strain using ROC curve was 2.57. Area under the curve (AUC) was found to be 0.933 (0.879-0.987) p<0.001.

Conclusion: Sonoelastography is the non-invasive modality of choice with high diagnostic accuracy in differentiating between malignant and benign nodules. Key Words: Sonoelastography, Strain elastography, Thyroid nodule, Benign, Malignant, Sensitivity, Specificity.