THYROID SCINTIGRAPHY AND PERCHLORATE DISCHARGE TEST IN THE DIAGNOSIS OF CONGENITAL HYPOTHYROIDISM

Quantitative thyroid scanning using low doses of technetium-99m sodium pertechnetate was performed on 147 infants (55 males and 92 females) with congenital hypothyroidism detected through the national neonatal screening programme. Thirty-two (21.8%) were athyrotic, while 62 (42.2 %) had an ectopic thyroid and 53 (36%) had a eutopic gland with increa sed Tc-99m uptake (mean 17%; range, 5%-38%). The perchlorate discharge test (PDT) was performed in nine of the infants with ectopic glands a nd 15 with eutopic glands; the findings were consistent with an organi fication defect in 22 cases (seven ectopic and 15 eutopic). Thyroid sc intigraphy and PDT can add useful aetiological, genetic and prognostic information in the clinical evaluation of infants with congenital hyp othyroidism detected by neonatal screening.