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Updated: Aug 19, 2026
A Novel Method: Super-selective Adrenal Venous Sampling
Published on: September 15, 2017
Added value of multiparametric MRI for diagnosing subcentimeter functional adrenal nodules in primary aldosteronism
Xiaoli Meng1, Zhiyong Quan1, Linni Fan2,3
1Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
Objective:
This study aims to evaluate the clinical utility of 68Ga-pentixafor PET/MRI in diagnosing primary aldosteronism (PA) in functional adrenal nodules, with a particular focus on subcentimeter nodules. Additionally, the diagnostic performance of integrated PET/MRI is compared to single-modality PET imaging.
Methods:
A total of 62 patients with clinical suspicion of PA were enrolled from a tertiary hospital in China. Prior to adrenalectomy, all patients underwent 68Ga-pentixafor PET/MRI, followed by CXCR4 and CYP11B2 immunohistochemical analysis post-surgery. Adrenal lesions were stratified into two size groups: ≥ 1 cm and < 1 cm. Quantitative PET parameters, including SUVmax, SUVmean, and lesion-to-liver uptake ratio (LLR), were evaluated alongside MRI parameters such as outphase/inphase signal ratio (OIR), relative percent washout (RPW), T2-weighted image intensity, apparent diffusion coefficient (ADC). Receiver operating characteristic (ROC) curve analysis was performed to establish diagnostic thresholds. Comparative analyses were conducted between single-modality PET and integrated PET/MRI for diagnostic accuracy.
Results:
Among 62 patients, 74 adrenal lesions were confirmed pathologically, comprising 37 aldosterone-producing adenomas (APA, ≥ 1 cm), 21 aldosterone-producing micronodules (micro-APA, < 1 cm), and 16 non-functioning adenomas (NFA). Key PET/MRI parameters, including SUVmax, SUVmean, LLR, OIR, and RPW, showed significant differentiation between functional adrenal nodules and normal adrenal glands (P < 0.001). For nodules ≥ 1 cm, the PET SUVmax threshold of 7.87 achieved a sensitivity of 92.3% and specificity of 95.0% for APA diagnosis. For nodules < 1 cm, the PET SUVmax threshold of 6.49 yielded a sensitivity of 68.8% and specificity of 83.3% for micro-APA diagnosis. Integrated PET/MRI significantly improved the diagnostic sensitivity for PA subcentimeter nodules from 68.8% (with PET alone) to 87.5%, and increased the area under the ROC curve from 0.760 to 0.854, with no significant reduction in diagnostic specificity.
Conclusion:
68Ga-Pentixafor PET/MRI demonstrated high diagnostic accuracy for functional adrenal nodules in PA, particularly enhanced sensitivity for subcentimeter nodules compared to PET alone.
