Primary Aldosteronism Classification With 18-Oxocortisol and Gallium-68-Pentixafor Positron Emission Tomography/Computed Tomography.

Objective: This study aimed to explore the noninvasive and accurate evaluation methods of primary aldosteronism (PA) classification.

Methods: There were 99 patients with aldosterone-producing adenoma (APA) and 61 with idiopathic hyperaldosteronism recruited in this study. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gallium-68 (⁶⁸Ga)-pentixafor positron emission tomography (PET)/computed tomography (CT) were performed in this cohort. Statistical analysis was used to calculate the diagnostic efficiency of single or double methods.

Results: In steroid profiling detected by LC-MS/MS, the average levels of 6 steroids apart from aldosterone in the APA group were higher than those in the idiopathic hyperaldosteronism group. The differential diagnostic efficiency of 18-oxocortisol (cutoff value at 0.132 ng/mL) was greater than other steroids, with a sensitivity of 75.3% and specificity of 91.2%. As for ⁶⁸Ga-pentixafor PET/CT, visual analysis showed a sensitivity of 93.7% and specificity of 56.3%. At the optimum maximum standardized uptake value of 8.00, the sensitivity was 69.8%, and the specificity was 93.7%. Taking into account the 18-oxocortisol level and ⁶⁸Ga-pentixafor PET/CT maximum standardized uptake value, 100% of patients with double positive results were placed in the right APA subtype. If the 18-oxocortisol level with ⁶⁸Ga-pentixafor PET/CT visual analysis was combined for PA subtyping, the sensitivity of at least 1 positive was 95.2%, and a total of 87.2% of patients could be classified correctly.

Conclusion: The LC-MS/MS and ⁶⁸Ga-pentixafor PET/CT have great advantages on the subtyping of PA. There was a high accuracy of the combination of the 2 methods, which will contribute to avoid an unnecessary adrenal venous sampling operation before surgery for most patients with PA.