[Thallium-technetium scintigraphy for presurgical localization of parathyroid adenomas and hyperplasia]

The purpose of this study was to assess the value of parathyroid Thallium 201-Technetium 99m scintigraphy in 45 patients with hyperplasia or parathyroid adenomas with or without associated thyroid abnormalities. The prevalence of parathyroid abnormalities found during examination was 42/45: 36 adenomas (35 patients) and 16 hyperplasias (7 patients). Seventeen patients (38%) had thyroid abnormalities. The sensitivity and specificity of the three image analysing methods (visual analysis, simple subtraction, sophisticated subtraction) were determined by assessing answers given by 3 observers. The population was divided into 6 groups: adenomas and hyperplasias with (group I, n = 42) or without (group II, n = 25) thyroid abnormalities, adenomas alone with (group III, n = 35) or without thyroid abnormalities (group IV, n = 22), hyperplasias alone with (group V, n = 7) or without thyroid abnormalities (group VI, n = 5). The highest overall sensitivity was obtained, whichever the group, by applying the sophisticated image subtraction technique; for any given method, the best results were observed in the group comprising adenomas alone, especially without associated thyroid abnormalities. On the other hand, in the groups comprising hyperplasias alone, sensitivity was low. This leads us to conclude that, together with ultrasonography, parathyroid scintigraphy is currently the best preoperative technique for localizing parathyroid adenomas, even in the presence of associated thyroid abnormalities. However this must be carried out in conjunction with a sophisticated image subtraction technique.