Scintigraphic imaging of congenital hypothyroidism: Report on 181 cases of infants

Introduction. - Incidence of congenital hypothyroidism (CH) is about one in 3000 newborn and CH is the main cause of avoidable mental retardation and abnormality of growth. It may be permanent or transient. Thyroid scintigraphy allows in most of cases to specify the type of CH. The aim of this study was to clarify the contribution of scintigraphy for the diagnosis, management and prognosis of the children with CH, on basis the experience from the Nuclear Medicine department of Armand-Trousseau Children Hospital. Patients and methods. - We retrospectively reviewed all the children (0-3 months) referred between January 2005 and December 2008 to the pediatric hospitals in Paris for the management of neonatal hypothyroidism. A planar scintigraphic acquisition, including stomach and bladder, was done 1 h after intravenous injection of 1.1 MBq of I-123. When the thyroid was normally located, a perchlorate discharge test was performed. Results. - During the study period, 181 infants had thyroid scintigraphy for CH. The sex-ratio girl/boy was 1.7. Fifty-six percent had thyroid dysgenesis (21% agenesis, 35% ectopia). Seventy-nine patients (44%) had an eutopic thyroid. A significant association was observed between TSH levels and etiology of HC, and between TSH levels and the percentage of iodine uptake decrease after the perchlorate discharge test: the highest level of TSH was observed in the case of athyreosis and when perchlorate test was very disturbed (fall of thyroid activity greater than 70%). Conclusion. - Thyroid scintigraphy in association with ultrasound permits a precise characterization of the etiology of CH. These examinations help clinicians to ensure an optimal management of patients by identifying those with most severe hypothyroidism, and to inform parents most completely on duration of treatment and existence of a potential risk during a future pregnancy. (c) 2012 Elsevier Masson SAS. All rights reserved.