Objectives: The rate and impact of thyroglossal duct remnant (TGDR) visualization in patients with hypothyroidism
after total thyroidectomy for differentiated thyroid carcinoma (DTC) have not yet been fully determined. The aim
of this study was to assess the rate of TGDR visualization in post total thyroidectomy whole body scan (WBS)
for DTC and to evaluate its impact on the outcome of I‑131 ablation. Methods: A total of 60 consecutive DTC
patients (51 papillary thyroid Ca., and 9 Follicular thyroid Ca.), underwent total thyroidectomy, followed by
WBS (using I‑131 in 28 patients and I‑123 in 32 patients), neck ultrasound (US), thyroglobulin (Tg) and Tg
anti‑bodies (TgAb) assay after 40 days and subsequent I‑131 ablation. At 6 months later follow‑up I‑131 WBS,
neck U/S, Tg and TgAb were performed following suspension of L‑thyroxine for 1‑month (thyroid stimulating
hormone [TSH] >30 μIU/ml) in 53 patients and following recombinant human TSH stimulation in seven
patients. Results: Of the studied 60 patients, 19/60 (31.7%) had a linear or focal radioactivity at the superior
midline of the neck, suggesting TGDR (Group 1), and 41/60 (68.3%) had no uptake to suggest TGDR (Group 2).
No significant difference regarding age, gender and histopathology between both groups. Neck US showed no
evidence of thyroid tissue in the superior midline of the neck in both groups, and only a small or no residual
thyroid tissue in patients of Group 1. There was a significant successful I‑131 ablation rate among patients of
group 1 compared to group 2 (79% in Group 1 vs. 41.5% in Group 2) (P = 0.007). Conclusions: Thyroglossal duct
remnant visualization on WBS of hypothyroid subjects after total thyroidectomy suggests presence of only a small
or no residual functioning thyroid tissue at the thyroid bed and can predict a good response to I‑131 ablation.