Siva P. Raman MD, Presenter: Nothing to Disclose

Satomi Kawamoto MD, Abstract Co-Author: Research support, Siemens AG

Yifei Chen BS, Abstract Co-Author: Nothing to Disclose

Pamela Tecce Johnson MD, Abstract Co-Author: Research funded, Becton, Dickinson and Company

Mark Lewis Lessne MD, Abstract Co-Author: Nothing to Disclose

Elliot K. Fishman MD, Abstract Co-Author: Research support, Siemens AG Advisory Board, Siemens AG Research support, General Electric Company Advisory Board, General Electric Company Co-founder, HipGraphics, Inc

Primary hyperaldosteronism usually results from an aldosterone-secreting adenoma (ASA) or bilateral adrenal hyperplasia (BAH), and adrenal vein sampling (AVS) is considered the goal-standard for differentiating these two possibilities.  This study compares MDCT with adrenal vein sampling, and seeks to determine whether MDCT alone may be sufficient in some patients.

MDCTs of 43 adult patients with biochemical evidence of hyperaldosteronism and who had undergone AVS were reviewed retrospectively by 2 radiologists blinded to AVS results. Readers recorded the presence/size of adrenal nodules and measured adrenal gland limbs. AVS results and MDCT findings were then correlated. 

13 patients had bilateral adrenal nodules, 14 had unilateral nodule on the right, 14 had unilateral nodule on the left, and 2 had no nodule on either side. AVS suggested ASA on the right in 22, ASA on the left in 19, and BAH in 3 subjects. The presence of a nodule was associated with sensitivities of 82-88%, specificities of 57-72% and accuracy of 47-81% for predicting positive AVS. Of the 28 patients with a single unilateral nodule on MDCT, the side of the nodule correctly correlated with AVS in 24 (86%).  In all of the 4 incorrect cases, the nodule measured < 2 cm, and in 2 cases AVS suggested BAH, while the wrong side was localized on CT in 2 cases.  Of the 13 patients with bilateral nodules, 12 localized unilaterally to one side on AVS, while 1 had BAH.   Of these 13 cases, there was significant discrepancy in size of the bilateral nodules (>1 cm) in 5 cases, in all of which AVS localized to the side of the larger nodule. In the right adrenal gland, functioning nodules (mean 21.8 mm) were signficantly larger than nonfunctioning nodules (8.3 mm) (p=0.002). On the left side, there was no difference in nodule size between functioning and nonfunctioning lesions (17.1 mm vs 18 mm, p=0.852).    

In primary hyperaldosteronism, MDCT can accurately predict the presence of a uniliateral ASA in cases with a unilateral nodule measuring > 2 cm, or in cases with bilateral adrenal nodules where there is a size discrepancy of the nodules of > 1 cm.

In certain limited cases, it might be possible to perform adrenalectomy based on MDCT results alone without AVS. However, in cases with a unilateral small nodule or bilateral nodules without a size discrepancy, AVS is critical for correct localization and diagnosis.

Raman, S, Kawamoto, S, Chen, Y, Johnson, P, Lessne, M, Fishman, E, Diagnostic Imaging in Patients with Primary Hyperaldosteronism: Correlation of MDCT Findings with Adrenal Vein Sampling.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14007454.html