To Evaluate the Diagnostic Accuracy of Ultrasound Criteria for the Depiction of Benign or Malignant Thyroid Nodule by Using Tissue Diagnosis as Reference Standard
Depiction of Benign or Malignant Thyroid Nodule
Background: High-resolution ultrasonography is a very sensitive imaging modality for examination of the thyroid gland and associated abnormalities. It is noninvasive, widely available, less expensive, and does not use any ionizing radiation. Further, real time ultrasound imaging helps to guide diagnostic and therapeutic interventional procedures (FNAC and Biopsy) in cases of thyroid disease. Objectives: To study the diagnostic accuracy of ultrasound criteria’s for the depiction of benign or malignant thyroid nodule and their correlation with cytology or histopathology. Subjects and Methods: The study included 50 patients who were referred for ultrasound with clinical suspicion of thyroid lesions. The ultrasound diagnosis was compared to the final diagnosis made on cytology or histopathology, and the ability of ultrasound in differentiating between a benign or malignant lesion was determined. Results: The ultrasound features favoring a malignant lesion included – solid consistency (Sn 92.3%; Sp48.6%; p=.009), hypoechoic echo-pattern (Sn 100%; Sp 54.5%: p=.004), micro-calcification (Sn 69.3%; Sp97.3%; p=.000), taller than wider shape (Sn 53.8%; Sp 89.1%; p=.001), ill-defined margins (Sn 61.5%;Sp 91.9%; p=.000) and internal vascularity (Sn 84.6%; Sp67.5%;p=.001). The ultrasound diagnosis was in agreement with the final diagnosis in 90% of the cases.The overall sensitivity, specificity and PPV of ultrasound in identifying a malignant lesion was 92.31%, 97.30%, and 92.31% respectively. Conclusion: Ultrasound is an excellent non-invasive modality to evaluate thyroid nodules. It is a highly sensitive imaging modality for identifying and characterizing a lesion as benign or malignant.