Pp.32.13: can 128-slice dual-source ct replace adrenal vein sampling for subtyping patients with primary aldosteronism?

Objective: Adrenal venous sampling (AVS) is the preferred method to distinguish excess unilateral from bilateral aldosterone secretion in patients with primary aldosteronism. Although it is invasive and expensive conventional CT adrenal imaging is considered to be inferior to AVS. To examine whether 128-slice dual-source CT using strict standardized radiological diagnostic criteria may approach the diagnostic performance of AVS. Design and method: From May 2012 to August 2014 we performed both AVS and 128-slice dual-source CT in 50 consecutive patients with PA. AVS was pursued after correction of hypokalemia and adjustment of antihypertensive therapy, under continuous ACTH infusion. Blood samples were taken from both adrenal veins (AV) and the lower caval vein (LCV). Selective cannulation was defined as an AV/LCV ratio for cortisol of ≥3. Lateralization was defined as a dominant/non-dominant ratio for aldosterone-to-cortisol of ≥4. In addition suppression of the contralateral side was required. Computer tomography imaging was performed using 128-slice dual-source CT with a 1mm-thickness slice. As a diagnostic criterion of adrenal nodule on CT-scan a focal change > 7 mm was used. A diffuse thickening of adrenal limbs > 5 mm was thought to fit with adrenal hyperplasia. A unilateral change (adenoma/hyperplasia) was defined as a change within one single adrenal gland with normal contralateral gland. Bilateral abnormalities included bilateral adenomas and/or bilateral adrenal hyperplasia. Results: The cannulation failed in 2 (4%) subjects. No complications were observed during and after procedures. Twentythree patients (48%) demonstrated unilateral aldosterone production (14 left-sided, 9 right-sided), and 25 (48%) patients were characterized by bilateral aldosterone production. In 43,8% of the patients there was disagreement between results of AVS vs CT. In 11 subjects (22.9%) a unilateral change was found on CT-scan, while there was no lateralization on AVS. In 7 patients (14,6%) CT–scan revealed bilateral abnormalities or symmetrical normal adrenal glands whereas in AVS unilateral aldosterone secretion was observed. In 2 cases there was complete discordance between the affected sides as diagnosed by CT and AVS. Conclusions: Despite adopting strict radiological criteria to differentiate uni- from bilateral disease, the diagnostic performance of 128-slice dual-source CT-scan is inferior to that of AVS.