SUN-253 - Diagnostic Accuracy of 68Ga-Pentixafor PET/CT in Identifying Functional Primary Aldosteronism Lesions with Different Features in CT Images

Background:
Numerous studies have confirmed the value of 68Ga-pentixafor PET/CT for PA subtyping. However, some diagnostic errors remain. The features of adrenal lesions on CT images vary across patients with PA. To date, no study has investigated whether the diagnostic performance of PET/CT varies among adrenal lesions with different imaging features.

Aim:
To define the features of the adrenal lesions in CT images of patients with PA associated with better 68Ga-pentixafor PET/CT diagnostic performance.

Methods:
This single-center, retrospective study was conducted at a tertiary hospital in China. Consecutive PA patients who underwent both adrenal CT and 68Ga-pentixafor PET/CT imaging were included. PET/CT image interpretation involved visual analysis, and semiquantitative parameters, including the SUVmax, liver-to-lesion ratio (LLR), and lesion-to-adrenal ratio (LAR), were recorded. According to the outcome after surgery or the results of AVS, patients were classified as having unilateral PA or bilateral PA, and their lesions were categorized as functional or nonfunctional. Based on adrenal CT imaging features, the lesions were classified as adenomas or nonadenomas. ROC curve analysis was performed to evaluate the accuracy of PET/CT for identifying adrenal lesions with different imaging features.

Results:
A total of 93 patients with postoperative follow-up data or successful AVS were analyzed (45.2% female; mean age 49.3 ± 11.6 years). A total of 136 adrenal lesions, including 81 typical adenomas and 55 nonadenomas, were detected by CT. Lesions characterized as adenomas exhibited significantly higher 68Ga-pentixafor uptake than nonadenoma lesions did. Visual analysis yielded a positivity rate of 90.1% in the adenoma group, which was significantly higher than the 18.2% for in the nonadenoma group (P < 0.001). Semiquantitative analysis revealed that all the parameters were significantly greater in the adenoma group than in the nonadenoma group (P < 0.001). Furthermore, the AUCs of the four PET/CT indices for identifying functional lesions in the adenoma group ranged from 0.828 to 0.915, which were consistently greater than those in the nonadenoma group (0.541–0.613). Notably, visual analysis demonstrated superior diagnostic efficacy within the adenoma group, yielding a sensitivity of 97.3%, specificity of 85.7%, and accuracy of 96.3%. In contrast, the diagnostic sensitivity of visual analysis in the nonadenoma group was only 33.3%.

Conclusions:
The diagnostic performance of 68Ga-pentixafor PET/CT is better for PA patients with adenomas than for those with nonadenomas by CT. Therefore, 68Ga-pentixafor PET/CT could serve as a primary subtype modality in patients with adenoma lesions on CT. Further multicenter prospective studies are warranted to validate these findings.

*Unless otherwise noted, all abstracts presented at ENDO must not be released to the press or the public until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.*