[Evaluation of the localizing procedures of primary aldosteronism]

The validity of preoperative localizing procedures was studied in 36 patients with primary aldosteronism due to adrenal adenoma, all of whom were confirmed surgically. Adrenalectomy resulted in normalization of blood pressure and serum potassium. Furthermore, we reviewed the correlation between mass size and some clinical parameters as well as the accuracy of localization procedures. Adopted localization procedures included imaging techniques such as abdominal ultrasonography, computed tomography (CT), adrenal scintiscan, magnetic resonance imaging (MRI) and adrenal venography, and as a functional diagnostic procedure, adrenal venous sampling. Among imaging procedures, CT was the most effective to detect adrenal mass with as high accuracy as 88%, adrenal venography following with 83%. The correct localization was obtained in 60% by adrenal scintiscan and only 39% by ultrasonography. Although MRI was performed only in 2 cases, the smallest adenoma could be detected only by MRI, suggesting that MRI might be useful to detect microadenoma by increased signal intensity. Although adrenal scintiscan had been considered to be useful because of its functional diagnostic characteristics, the correct localization was as low accuracy as 60%, which was not improved by the administration of dexamethasone. To assess the accuracy of lateralization for adrenal venous sampling, we calculated the ratio of aldosterone concentration in adrenal vein to inferior vena cava. When the ratio was more than 10 or less than 1, the correct localization was made.(ABSTRACT TRUNCATED AT 250 WORDS)