2025 Volume 52 Issue 5 Pages 163-170
Purpose: To investigate the utility of ultrasonography (US) for delineating the left adrenal gland using the left renal vein (LRV) as a landmark, based on anatomical analysis of computed tomography (CT) images. Methods: (i) The position of the left adrenal gland was analyzed in relation to the abdominal aorta (Ao), celiac artery (CA), superior mesenteric artery (SMA), and LRV in 50 cases where CT was performed for suspected left adrenal nodules. Based on this analysis, a novel method for delineating the left adrenal gland was developed. (ii) Three technicians compared the delineation of the left adrenal gland using the conventional method (left intercostal scan) and the novel method in 148 normal cases with a history of CT imaging and six nodule cases encountered during the same period. Results: (i) All left adrenal glands were located on the left side of the Ao and cephalad to the LRV, with the majority (82%) positioned between the CA and SMA. Based on these findings, a transverse midline scan to delineate the LRV followed by a search of the region left of the CA-SMA origin (hereafter referred to as the “novel method”) was considered the most effective approach. (ii) The delineation rate of the left adrenal gland using the novel method was 55% in normal cases and 100% in cases with nodules, significantly higher than the conventional method (9% in normal cases and 50% in nodular cases). The delineation rate of the LRV in the non-visualization group was low (21%), suggesting that elevated BMI notably impacts the LRV delineation status. Conclusion: The delineation method using the LRV as a landmark for the left adrenal gland is considered useful for detecting both normal and nodular cases.
