Pustaka Ilmiah Universitas Padjadjaran

Abstrak

Retention Index (RI) Of Tc-99m Mibi Thyroid Scintigraphy, Ultrasonography (USG), And Fine-needle Aspiration Cytology (FNAC) In The Assessment Of Thyroid Nodule

Background: Thyroid nodules are frequently encountered in clinical practice and most of which are benign in nature.However, it is still a challenge to effectively distinguish malignant nodules from benign since FNAC as the primarydiagnostic tool does not give a definitive diagnosis in 10 – 42% of case (indeterminate results). This prospective study wasdesigned to appraise the significance of Tc-99m MIBI scintigraphy using retention index parameter, USG, and FNAC in differentiating benign from malignant thyroid nodules. Material and Method: Single injection, dual phase (15 and 120 minutes) thyroid scintigraphy using 370-555 MBq Tc-99mMIBI was performed in all participants. All participants also underwent ultrasonography, FNAC, and surgery. Results: The mean of retention index for malignant thyroid nodule (1.04±0.50) was significantly higher than benign thyroidnodule (0.58±0.17; p=0.001). Using threshold >0.58 as malignant thyroid nodule, the sensitivity, specificity, NPV, PPV, andaccuracy for Tc-99m MIBI were 87.5%, 70.6%, 92.3%, 58.3%, and 80% respectively. Sensitivity, specificity, NPV, PPV,and accuracy for USG were 87.5%, 52.9%, 90%, 46.7%, and 64%. FNAC showed 14 benign nodules, 6 indeterminate, and 5malignant nodules. Diagnostic performance of Tc-99m MIBI thyroid scintigraphy was not significant different from USG,but RI was capable to detect 5 out of 6 (83%) participants with indeterminate FNAC. Conclusion: RI of Tc-99m MIBI scintigraphy may be useful in the assessment of thyroid nodule, especially those withindeterminate FNAC result.