Diagnostic Performance of Gray Scale and Doppler Sonography Using ATA Thyroid Nodule Sonographic Patterns, Quantitative Doppler Parameters in Evaluation of Thyroid Nodule and Correlation with FNAC

Abstract

Background: Thyroid nodule is common endocrine disease. FNAC is gold standard but not sensitive test. Ultrasonography features are known for risk stratification of thyroid nodule, and identifying which nodules can be triaged for repeat FNAC after negative FNA results as well. Many ultrasound risk stratification classifications of thyroid nodule are existing. But, none of these classification systems have been widely adopted worldwide due to their inherent limitations. Hence scientific data on USG thyroid needs updation to enhance the diagnostic performance of ultrasonography.

Aims and Objectives: To assess the diagnostic performance of Grayscale sonography using ATA thyroid nodule sonographic patterns; and doppler sonography using spectral doppler parameters, i.e., RI and PI alone and in combination in determining benign and malignant thyroid nodule compared to gold standard FNAC.

Materials and Methods: Prospective Observational Cross sectional diagnostic study. On all patients gray scale HRUS, Doppler sonography performed. Resistance Index (RI) and Pulsatility Index (PI) were assessed with spectral doppler technique.

Results and Summary: In our study diagnostic performance of quantitative doppler parameters, i.c., RI and PI evaluated with ROC analysis revealed RI (AUC -0.813) is better predictor for malignancy than PI (AUC -0.788). An optimum cutoff of RI is>0.67. with good sensitivity 73.7%, specificity 81.2%, PPV 60.90%, NPV 88.6% to distinguish malignant from benign lesion.

Conclusion: In our study quantitative doppler parameter, i.c., RI alone showed higher diagnostic performance to distinguish malignant from benign lesion compared to gray scale sonography and combined gray scale and doppler sonography.