[Scintigraphic discordances between technetium 99m and iodine 131 in the study of thyroid nodules].

Eighty thyroid nodules found to be hyperfixating, isofixating or heterogeneous after an initial scintigraphy with Technetium 99m were studied comparatively using iodine 131. Differences in the apparent activity of the nodule and the extra-nodular parenchyma were found in one third of cases. A "cold nodule" appearance, not seen with techneitum was found in 8 cases at the time of the examination using iodine. Five of these patients underwent operation, the diagnosis being a carcinoma in one.