Respiratory triggered 3D bSSFP MRI enables accurate noninvasive localization of the right adrenal vein confluence in primary aldosteronism

Catheterization of the right adrenal vein (RAV) is a technically challenging step in adrenal venous sampling (AVS) for primary aldosteronism. Accurate preprocedural evaluation of RAV anatomy is essential for procedural success. To assess the feasibility of respiratory-triggered three-dimensional balanced steady-state free precession (RT-3D bSSFP) magnetic resonance imaging for visualizing the confluence of the RAV with the inferior vena cava (IVC), in comparison with contrast-enhanced computed tomography (CECT). In this retrospective study, we evaluated RT-3D bSSFP, CECT, and CV for RAV identification in patients who underwent all three examinations between April 2016 and March 2021. Two independent readers evaluated the vertical level of the RAV–IVC confluence relative to the vertebrae on each modality: CECT acquired during inspiration and RT-3D bSSFP obtained under free-breathing conditions. An independent interventional radiologist assessed catheter venography (CV) during both inspiration and expiration as the reference standard. Intraclass correlation coefficients (ICC [2,1]) were calculated for each modality. Additionally, the accuracy of detecting a common trunk with the accessory hepatic vein and inter-reader agreement (Cohen’s kappa) were assessed. Using CV as the reference standard and an equivalent margin of ± 0.5 vertebrae, and equivalence test was performed on CECT and RT-3D bSSFP, respectively. A total of 47 patients (38 males; mean age, 53 ± 12 years) were included. RT-3D bSSFP was successfully acquired in all cases. The ICC was 0.87 (95% confidence interval: 0.76, 0.93) for CECT and 0.81 (95% confidence interval: 0.67, 0.89) for RT-3D bSSFP. Equivalence in vertebral level was observed between RT-3D bSSFP and CV at expiration (p = 0.0023). Accuracy for detecting a common trunk was higher with RT-3D bSSFP than CECT, and inter-reader agreement was also higher (κ = 0.86 vs. 0.67). RT-3D bSSFP provides vertebral levels equivalent to CV at expiration within ± 0.5 vertebrae.