ACCURACY OF A NEW SONOGRAPHIC CLASSIFICATION SYSTEM IN DIFFERENTIATING BENIGN FROM MALIGNANT SOLID THYROID NODULES

Sonographic Classification For Benign and Malignant Solid Thyroid Nodules

Abstract

Objective: To determine diagnostic accuracy of sonographic criteria in differentiating benign from malignant
solid thyroid nodule by using new sonographic classification system.
Study Design: Cross sectional validation study.
Place and Duration of Study: Department of Radiology, Combined Military Hospital Multan from Oct 2014 to Mar 2015.
Material and Methods: A total of 150 consecutive cases of either sex ranging in age from 19-60 years with
palpable thyroid nodules referred for diagnostic workup were subjected to ultrasound (US) examination for
assessment of solid thyroid nodules and it was followed by US-guided fine-needle aspiration (FNA) of all solid thyroid nodules. Each of the biopsied nodule was subsequently placed into one of five categories on the basis of sonographic features i.e. “malignant,” “suspicious for malignancy,” “borderline,”“probably benign,” and “benign”. Evaluation of accuracy of sonographic diagnosis for solid thyroid nodule was done by comparingresults of fine needle aspiration biopsy (FNAB).
Results: The mean age of the patients (n=150) was 42.34 ± 4.78 years; seventy three percent (n=109) were females and twenty seven percent (n=41) were males. Frequency of thyroid nodules (on FNAB as gold standard) was revealed as 20.7% (n=31) malignant and 79.3% (n=119) benign, accuracy of a new sonographic classification system in differentiating benign from malignant solid thyroid nodules, keeping FNAB as gold standard showed 18.7% (n=28) true positive, 4.7% (n=7) false positive, 2% (n=3) false negative and 74.6% (n=112) true negative. Ultrasound finding has sensitivity of 90.3%, specificity of 94.12% and diagnostic accuracy of 93.3%.
Conclusion: Accuracy of a new sonographic classification system in differentiating benign from malignant solid thyroid nodules, while keeping FNAB as gold standard was high and is recommended for diagnosis of malignant solid thyroid nodules.