68Ga-pentixafor PET/CT Is a Supplementary Method for Primary Aldosteronism Subtyping Compared with Adrenal Vein Sampling

Purpose: To investigate the diagnostic efficacy of Ga-68-pentixafor positron emission tomography/computed tomography (PET/CT) in primary aldosteronism (PA) subtyping and lateralization of aldosterone secretion in PA patients. Procedures: 37 patients who were diagnosed with PA, were prospectively enrolled in the study, and underwent adrenal vein sampling (AVS) after Ga-68-pentixafor PET/CT was conducted. Lateralization index (LI), defined as aldosterone/cortisol ratio in the dominant side to the contralateral adrenal vein when bilateral adrenal vein catheterization succeeded, and the aldosterone/cortisol ratio in the left adrenal vein to IVC (LAV/IVC) when the catheterization of right adrenal vein failed, were applied to determine lateralization side. Statistical analysis was performed using SPSS 21.0. Results: The female proportion of all patients with PA was 32.4% (12/37), and the mean age was 51.3 +/- 10.9 years. Patients with bilateral adrenal mass accounted for 54.1% (20/37), and 10 of them (27.0%) had adrenal hyperplasia or adrenal nodules <= 1.0 cm. In all 37 patients, the sensitivity, specificity and accuracy of Ga-68-pentixafor PET/CT in distinguishing lateralization by visualization were 89.3%, 77.8% and 86.5%, respectively. The area under the ROC curve for detecting positive lateralization based on the value of Ga-68-pentixafor SUVmax was 0.750 (95%CI 0.578-0.922, p = 0.026). The optimum SUVmax cut-off value was 6.86, with the sensitivity of 78.6%, specificity of 66.7%, and accuracy of 78.4%. Defining SUV ratio as SUVmax/SUV of contralateral adrenal gland, the area under the ROC curve for identifying lateralization based on the SUV ratio was 0.710 (95%CI 0.500-0.921, p = 0.061). The optimum SUV ratio cut-off was 2.40, with the sensitivity of 60.7%, specificity of 88.9%, and accuracy of 67.6%. The consistency of Ga-68-pentixafor PET/CT with AVS was of no significant difference between patients with bilateral adrenal lesions (80.0%, 16/20) and unilateral lesion (94.1%, 16/17; p = 0.737), and no significance was revealed in the consistency between patients with adrenal hyperplasia or adrenal lesion of diameter <= 1 cm (81.8%, 9/11) and those with adrenal lesions > 1 cm (88.5%, 23/26; p = 0.884). Conclusions: Ga-68-pentixafor PET/CT showed at least 80% consistency for the lateralization in patients with PA compared with AVS, even in those presented with bilateral adrenal hyperplasia. Visual analysis exhibited better diagnostic efficacy compared with SUVmax or SUVmax/SUV of the contralateral adrenal gland.( ChiCTR2300073049. Registered 30 June 2023. Retrospectively registered).