Comparison of Different Diagnostic Criteria of 68Ga-Pentixafor PET/CT for the Classification of Primary Aldosteronism

Background: 68Ga-Pentixafor positron emission tomography/computed tomography (PET/CT) is an emerging method for the classifying primary aldosteronism (PA). How to use this method for PA classification is still controversial. Methods: A retrospective study was conducted in patients with PA who underwent PET/CT. These patients had a classification diagnosis of unilateral PA (UPA) or bilateral PA (BPA) based on adrenal venous sampling or post-surgical outcomes. Area under the receiver operating characteristic curve (AUC), specificity and sensitivity were used to analyze the accuracy of the lateralization index (LI) based on adrenal maximum standardized uptake value (SUVmax), dominant side SUVmax adjusted by liver, dominant side of SUVmax and visual analysis. Results: A total of 208 PA patients were included, with 128 UPA and 80 BPA. The AUC for diagnosing UPA using LI and visual analysis were 0.82 [95% CI, 0.77-0.87] and 0.82 (95% CI, 0.76-0.87), respectively, higher than the dominant side of SUVmax [0.72, (95%CI, 0.65-0.78)] and dominant side SUVmax adjusted by liver [0.71, (95%CI, 0.64-0.77)]. Visual analysis showed a sensitivity of 0.73 (95%CI,0.65-0.81) and a specificity of 0.88(95%CI,0.80-0.95). The LI cutoff of 1.50 resulted the highest Youden Index of 0.59, with a sensitivity of 0.68 (95%CI,0.59-0.76) and a specificity of 0.91 (95%CI,0.83-0.96). When the LI cutoff was increased to 1.65, the sensitivity reduced to 0.61 (95%CI,0.53-0.70), while the specificity increased to 0.96 (95%CI,0.89-1.00). Conclusion: Both LI and visual analysis of PET/CT could be used in the classification diagnosis of PA. Nevertheless, visual analysis is more sensitive, and LI is more advantageous in specificity.