Use of 3‐Dimensional Sonography for Prenatal Evaluation and Follow‐up of Fetal Goitrous Hypothyroidism

Abstract

Objective. Fetal goitrous hypothyroidism is a rare and potentially lethal condition. Consequently, itsearly diagnosis and treatment improve prognosis. Thyroid hormone measurement in either fetal serumor amniotic fluid implies important risks. Here we present a fetal goiter and the follow-up procedure,both done by the traditional method and by using 3-dimensional power Doppler (3DPD) imaging andvirtual organ computer-aided analysis (VOCAL). Methods.A single well-documented case of fetal goi-ter was followed weekly from 22 weeks until delivery. Amniocentesis for thyrotropin (TSH) and freethyroxine (T4) measurement as well as levothyroxine injections were performed at every control. Inaddition to amniocentesis, every control involved a sonographic evaluation, which included standardmeasurements of the gland and the capture of volume image sets in gray scale and 3DPD. Volume cal-culation of the gland was done using VOCAL software. Vascularization of the gland was evaluated bythe vascularization index (VI) included in the software. Results. With treatment, TSH levels decreasedprogressively until normalization. Free T4levels increased toward the end of gestation. Sonographicmeasurements of the gland volume to estimated fetal weight ratio decreased across treatment as lev-els of TSH did. The VI clearly depicted the vascular regression of the goiter, decreasing throughouttreatment in a consistent way until 24 hours before delivery. Conclusions.Gray scale and 3DPD eval-uations of the thyroid gland have been validated under similar circumstances and might be reliablecomplements to the invasive methods used in the management of this fetal condition. Key words:fetal hypothyroidism; goiter; 3-dimensional power Doppler sonography; 3-dimensional sonography;virtual organ computer-aided analysis.