DIAGNOSTIC-VALUE OF (123)IODINE SCINTIGRAPHY AND PERCHLORATE DISCHARGE TEST IN THE DIAGNOSIS OF CONGENITAL HYPOTHYROIDISM

Aim. Forty children suffering from congenital primary permanent hypoth yroidism were studied to determine the diagnostic impact of I-123 scin tigraphy in comparison to labaratory findings and ultrasonography. Met hods: In all patients I-123 scintigraphy was performed after intraveno us administration of 3,7 MBq I-123. If accumulation of the radiotracer in thyroid tissue occurred a perchlorate discharge test was performed subsequently. Results: Scintigraphy revealed athyrosis in 7 children. In 11 children a lingual thyroid was observed. Deficiency in iodine o rganification was diagnosed by a significant discharge of I-123 in 15 patients. In four of these children the diagnosis of Pendred's syndrom e could be established. Ectopic thyroid tissue could be demonstrated o nly by scintigraphy where clinical examination and sonography failed i n the diagnosis in all cases. Hypoplasia of the thyroid gland as it wa s diagnosed in 2 cases by ultrasonography appeared to be unlikely beca use a normal I-123 uptake was seen in these patients. In 2 patients wi th scintigraphic proven athyrosis an orthotopic gland had been conside red by ultrasound. In 50% of our patients the final diagnosis could on ly be established if I-123 scintigraphy and perchlorate discharge test were performed. Conclusion. This findings suggest that scintigraphy i s indispensible in the correct diagnostic work up of congenital hypoth yroidism.