ObjectiveTo investigate the application value of ⁶⁸Ga-Pentixafor PET/CT targeting CXC subfamily receptor 4 (CXCR4) in the subtyping and precise localization of primary aldosteronism (PA).

MethodsThirty-three patients with PA confirmed by clinical examination and undergoing ⁶⁸Ga-Pentixafor PET/CT and adrenal vein sampling (AVS) in the Second Xiangya Hospital between July 1st 2022 and July 1st 2023 were prospectively enrolled (24 males, 9 females, age (49.6±10.3) years). Patients with a dominant side identified by PET/CT or AVS underwent unilateral adrenalectomy, while those without a dominant side received medical treatment. According to the standard of PA surgical outcome (PASO), patients underwent surgery were divided into unilateral PA (UPA) and bilateral PA (BPA) based on the pathological and follow-up results. Those who received medical treatment were BPA. The diagnostic efficacy of ⁶⁸Ga-Pentixafor PET/CT for UPA was calculated. The ROC curve was constructed to analyze the accuracy and optimal threshold of SUV _max, the ratio of lesion SUV _max to contralateral adrenal tissue SUV _mean (LCR), and the ratio of lesion SUV _max to liver SUV _mean (LLR) in the diagnosis of PA subtype. The correlation between the quantitative parameters and the clinical features and lesion width of the patients was evaluated by Spearman rank correlation analysis. The differences of LCR and LLR between different efficacy groups were compared by the independent-sample t test.

ResultsA total of 20 patients underwent unilateral adrenalectomy. Nineteen patients were finally diagnosed with UPA and 14 with BPA. The agreement rate of PET/CT and AVS was 81.8%(27/33), and both methods independently detected UPA that was negative in the other examination. The sensitivity, specificity, and accuracy of ⁶⁸Ga-Pentixafor PET/CT visual diagnosis of UPA were 18/19, 14/14, and 97.0%(32/33), respectively. ROC curve showed that the AUC of LLR for subtype diagnosis was 0.944, with the optimal threshold of 3.1. SUV _max, LCR, and LLR were positively correlated with aldosterone concentration ( r _s values: 0.35, 0.47, and 0.36, all P<0.05) and lesion width ( r _s values: 0.43, 0.49, and 0.58, all P<0.05). The LCR (3.9±2.2 vs 1.6±0.3; t=2.00, P=0.041) and LLR( 8.7±4.1 vs 4.2±1.3; t=2.06, P=0.045) of the dominant side lesions in patients who achieved complete biochemical and clinical cure were higher than those in patients with partial improvement.

Conclusions ⁶⁸Ga-Pentixafor PET/CT imaging can be used in the diagnosis and precise localization of PA subtype. It also can detect patients with PA which can be surgically cured but not detected by AVS, and the quantitative analysis may be valuable for prognosis prediction.