Respiratory Displacement of the Right Adrenal Vein: Comparison of Inspiratory and Expiratory Computed Tomography With Catheter Venography.

Objective: The aim of the study is to reveal the respiratory displacement of the right adrenal vein (RAV) to predict the exact location of the RAV during adrenal venous sampling (AVS).

Methods: Computed tomography (CT) scans obtained 45 seconds (breath-hold at inhalation) and 70 seconds (breath-hold at exhalation) after contrast material injection were compared to venograms of the RAV of patients with primary aldosteronism who underwent AVS between January 2016 and December 2020. The craniocaudal distance between the center of the Th11/12 disc and the RAV orifice was measured; the craniocaudal location of the RAV orifice was also specified relative to vertebral bodies and intervertebral discs on inspiratory phase CT (In-CT), expiratory phase CT (Ex-CT), and catheter venography. The transverse and vertical angles of the RAV and the position of the RAV orifice on the inferior vena cava (IVC) circumference were measured on In-CT and Ex-CT.

Results: In total, 51 patients (30 males, 21 females; mean age, 54.9 ± 11.1 years) were included. Craniocaudal distances between the center of the Th11/12 disc and RAV orifice were significantly different among the following 3 acquisitions: catheter venography versus In-CT (15.2 ± 8.4 mm); venography versus Ex-CT (5.6 ± 4.1 mm); and In-CT versus Ex-CT (19.6 ± 8.0 mm) (all, P < 0.001). The craniocaudal location of the RAV orifice on venography was significantly closer to that on Ex-CT than on In-CT (P < 0.001); measurements using venograms compared with In-CT and Ex-CT scans were within 1 level difference in 18 (35.3%) and 47 (92.2%) patients, respectively (P < 0.001). The vertical angle of the RAV was significantly more likely to be smaller on In-CT than on Ex-CT (P < 0.001).

Conclusions: RAV locations and angles change with respiratory motion. It is crucial to consider the respiratory phase of CT because it can enable a more accurate prediction of the location of the RAV during AVS.