Primary aldosteronism (PA) is common and accounts for at least 10% of the hypertensive population. Once PA is confirmed, differentiating between unilateral and bilateral disease is essential to guide therapeutic management, either with unilateral adrenalectomy for aldosterone producing adenoma (APA) or mineralocorticoid receptor (MR) antagonist for bilateral PA. The process of PA subtyping relies on adrenal vein sampling (AVS) which remains the gold standard to determine lateralization. However, AVS is operator dependent, labour intensive, expensive and invasive, also posing the risk of a failed or inconclusive study. Due to the high incidence of non-functional adrenal adenomas, CT imaging has not been shown to accurately localize the source of aldosterone excess, therefore it cannot be recommended as a tool for lateralization. With the rising cases of PA detected through screening, there is an increasing need for an accurate, non-invasive and cost-effective diagnostic modality to determine PA subtype.
Adrenal PET imaging, which employs a tracer (i.e., 11C-metomidate) directed at 11 beta-hydroxylase (CYP11B) in the adrenal glands have shown good accuracy and concordance with AVS results in detecting APA. However, a wider utility of this compound is limited by the short half-life of the radionuclide isotope, high cost of production and the lack of specificity for aldosterone synthase. More recently, a highly selective PET tracer for aldosterone synthase has been developed with a clinical trial currently underway. Another PET tracer directed at the chemokine receptor CXCR4 using Ga68-Pentixafor PET/CT has shown much promise in several recent clinical studies to detect APA in patients with PA. This symposium will share our experience with Ga68-Pentixafor PET/CT scan in our current prospective study of PA patients undergoing AVS.