title: Adrenal scintigraphy in primary aldosteronism. Improved visualization after long-term pre-treatment with dexamethasone.
abstract: Dexamethasone-modified adrenal scintigrams were performed on 13 patients with an aldosterone-producing adenoma and on one patient with an aldosterone-producing carcinoma. Adrenal scintigrams using 131I-19-Iodocholesterol were obtained after short pre-treatment with dexamethasone, while 131I-6 beta-Iodomethyl-19-Nor-Cholesterol scintigrams were performed after long-term pre-treatment with dexamethasone during 9-21 days. Using the former procedure the adrenal scintigrams correctly identified the adenoma in 3 of 8 patients, while with the latter procedure the adrenal scintigrams localized the adenomas in 8 out of 9 patients, including 3 patients in whom the former procedure had failed. The adrenal carcinoma was not visualized with 131I-6 beta-Iodomethyl-19-Nor-Cholesterol. Thus, the sensitivity of 131I-19-Iodocholesterol scintigrams to detect aldosterone-producing adenomas was only 37.5%. Uptake of radioactivity in the normal contralateral adrenal gland accounted for the low detection rate. On the other hand, the 131I-6 beta-Iodomethyl-19-Nor-Cholesterol scintigrams, performed after long-term pre-treatment with dexamethasone, had a sensitivity of 89%. It is suggested that long-term pre-treatment with dexamethasone contributed to the improved sensitivity by a more effective suppression of radioactivity uptake in the normal adrenal gland.
mesh_terms: D015071:19-Iodocholesterol; D000236:Adenoma / Q000000981:diagnostic imaging; D000293:Adolescent; D000301:Adosterol; D000310:Adrenal Gland Neoplasms / Q000000981:diagnostic imaging*; D000311:Adrenal Glands / Q000000981:diagnostic imaging*; D000328:Adult; D003907:Dexamethasone; D005260:Female; D006801:Humans; D006929:Hyperaldosteronism / Q000000981:diagnostic imaging*; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D013997:Time Factors
chemical_list: D007457:Iodine Radioisotopes; D015071:19-Iodocholesterol; D000301:Adosterol; D003907:Dexamethasone