Nor-iodo-cholesterol scintigraphy in the etiologic diagnosis of primary hyperaldosteronism

This study makes a comparison between the scintigraphy of 131I - 6β - methyl - iodo - 19 -nor-cholesterol (Norchol) and the tomo-densitometry (TDM) in defining the unilateral or bilateral character of the etiological process in primary hyperaldosteronisms. A lot of 35 patients presenting primary hyperaldosteronism were studied in no-drug conditions. The Norchol scintigraphy was achieved by the fourth day (4D) and eventually at 7D under the hindrance of dexamethasone. The etiological diagnoses were established, according to the overall clinical, biological, radiological, and scintigraphic results, as possible vein catheterism (9 cases), response to treatment and anatomical-pathologic data (11 cases). In 13 cases there was the Conn adenoma, in 13 cases, a primary hyperplasia with autonomous functional nodules and in 9 cases, a bilateral symmetric idiopathic hyperplasia. In case of Conn adenoma a unilateral lesion was found again, 11 times by scintigraphy and 8 times by TDM. In case of hyperplasia a bilateral aspect was well evidenced 21 times by scintigraphy and 12 times by TDM. In the single case of primary hyperplasia there was no significant fixation of Norchol. In 8 cases of primary hyperplasia and in 2 cases of idiopathic hyperplasia the TDM visualized a unique nodule only. In conclusion, the Norchol scintigraphy, which defined correctly the unilateral or bilateral character in 91% of our cases, relative to 60% for TDM, should be systematically achieved in any biologically-proved primary hyperaldosteronism cases