Neonatal hypothyroid disease - Absent salivary gland evident on technetium-99m pertechnetate scan

Purpose: Technetium-99m pertechnetate scintigraphy is a well-established te chnique for diagnosing congenital hypothyroid disease, However, the biodist ribution of pertechnetate (Tc0(4)(-)) in neonates and young infants is not well documented. The purpose of this study was to analyze and document the biodistribution of TcO4- in young infants. Materials and Methods: Scintigraphic studies of 31 patients being examined for hypothyroid disease were analyzed. All patients had elevated levels of thyroid-stimulating hormone, Dyshormonogenesis was diagnosed in 7 patients, ectopic thyroid glands in 19, and agenesis in 5, Results: Images of the neck, chest, and abdomen taken in the anterior and l eft lateral positions using a low-energy, all-purpose collimator were revie wed, Twenty-six of the patients had no accumulation of the isotope in the s alivary glands and 11 had no gastric uptake on either view, Conclusions: Based on the absence of salivary gland activity in the patient s examined, this study suggests that this is a normal finding in infants yo unger than 3 months, A lateral view of the neck with markers is sufficient to localize the thyroid grand, because any activity in the neck region woul d belong to the thyroid. Furthermore, poor and variable uptake of the isoto pe in the stomach may lead to false-negative results, so caution is urged i n the use of this tracer in Meckel's scintigraphy in young infants, particu larly if the study findings are within normal limits.