Role of thyroid scintigraphy vs. fine needle aspiration cytology in the clinical evaluation of solitary thyroid nodule a clinicoradiopathologic study

Abstract

To asses the value of qualitative and quantitative analysis of the radioisotopes ^99mTc tetrofosmin (Myoview) and ^99mTc (V) DMSA in the evaluation of malignant solitary thyroid cold nodule pre-operatively and to verify their exact value in diagnosis of differentiated thyroid carcinoma. In general there is a 5%-10% chance of malignancy in all thyroid nodules for the total population with higher incidence in single cold nodule than in multinodular goiter. The main role of ^99mTc (V) DMSA as a tumor imaging agent is in the diagnosis and follow-up of patients with medullary cancer thyroid. This work included 103 patients, 88 females and 15 males with a mean age of (37.86±13.59 years). All studied were subjected to history taking, proper clinical examination, thyroid function test profile, thyroid radioisotope imaging (^99mTc pertechnetate, ^99mTc tetrofosmin and ^99mTc (V) DMSA thyroid scans) and cytologic assessment of thyroid nodule proved to be cold on conventional thyroid scan. The current study combined both ^99mTc tetrofosmin and ^99mTc (V) DMSA to evaluate thyroid cold nodules and to verify possibility to differentiate between benign and malignant lesions preoperatively and as confirmed on cytology of lesions obtained by fine needle aspiration cytology (FNAC) modality. Our results showed that ^99mTc pertechnetate scan alone is not a reliable diagnostic tool to differentiate between benign and malignant thyroid nodules and that high early myoview uptake in the cold nodule is not specific for malignancy, it is also concluded that both ^99mTc tetrofosmin and ^99mTc (V) DMSA thyroid scans are valuable diagnostic tools when combined together.