Abstract 091: High Density Adrenal MRI Detects Clinically Relevant Aldosterone-producing Adenomas with Higher Precision than Computer Tomography
Background: Primary hyperaldosteronism is the most common cause of secondary hypertension, and part of the noninvasive diagnostic studies used to confirm the diagnosis include biochemical and computed tomography (CT) of the adrenal glands. If no adenomas are seen on imaging, invasive adrenal vein sampling, to diagnose unilateral disease amenable to surgery, is limited to cases with high pre-test probability. We developed a dedicated MRI protocol and investigated whether surgically-treatable unilateral aldosterone-producing adenomas missed by CT could be detected using this protocol.
Methods: We developed a dedicated MRI protocol of the adrenal glands using thin single shot T2-weighted scans, noncontrast MR angiography, reduced field of view diffusion, and dynamic contrast enhancement through the kidneys and adrenal glands with gadolinium (or ferumoxytol if eGFR < 30 mL/min/1.73m2). We then enrolled patients with biochemical evidence of primary hyperaldosteronism without evidence of adrenal lesions by CT and performed MRI.
Results: Five subjects with primary hyperaldosteronism and negative CT underwent MRI. Each had adrenal nodules by MRI. In three cases, a single, unilateral adrenal nodule was detected and followed up with ipsilateral lateralization of aldosterone/cortisol production by adrenal vein sampling. These patients underwent laparoscopic adrenalectomy with histologic diagnosis of an aldosterone-producing adenoma with significant improvement in blood pressure and/or reduction in antihypertensive medications. In the other two cases, adrenal nodules were found but adrenal vein sampling detected no lateralization of aldosterone/cortisol ratio.
Conclusions: As proof of concept, MRI of the adrenal glands may be a superior imaging modality to diagnose subtypes of primary hyperaldosteronism. With identification of adrenal lesions, this may capture additional cases of secondary hypertension than are amenable to surgical cure improving outcomes and quality of life for patients with severe hypertension. Moreover, it may imply that some cases of primary hyperaldosteronism ascribed to bilateral adrenal hyperplasia may indeed be due to aldosterone-producing adenomas undetectable by CT.
Author Disclosures: I. Raber: None. R. Isom: None. J. Louie: None. S. Vasanawala: None. V. Bhalla: H. Other; Modest; DSMB - Kona Medical, DSMB - Valencia Technologies.
- © 2015 by American Heart Association, Inc.