Differentiation between suppressed thyroid tissue and thyroid hemiagenesis with Tc-99m pertechnetate radionuclide...

Tc-99m pertechnetate thyroid angiography was performed on 62 patients who had unilateral thyroid enlargement and no radionuclide uptake in the contralateral lobe in an attempt to differentiate suppressed thyroid tissue from thyroidal hemiagenesis. In 55 cases of toxic, autonomous functioning thyroid nodules, the suppressed contralateral lobe was unequivocally demonstrated, the flow study showing tracer coursing through this tissue in the sequential arterial images. No arterial flow was demonstrable on the rapid sequence imaging in the agenetic lobe in seven patients who had thyroidal hemiagenesis. Radionuclide thyroid angiography appears a safe, simple, and accurate one-step study for distinguishing between suppressed thyroid tissue and thyroid hemiagenesis and precludes the requirement for additional studies, such as the thyrotropin stimulation test and Tl-201 scintigraphy.