Morphological Analysis of Gastrorenal Shunts Using Three-dimensional Computed Tomography-Portography: A Comparison with Intraoperative Venography During Balloon-occluded Retrograde Transvenous Obliteration

Purpose Balloon-occluded retrograde transvenous obliteration (BRTO) is an endovascular treatment for gastric varices. Successful BRTO requires deep catheterization of the gastrorenal shunt which constitutes the main efferent pathway of the varices. However, the complex anatomy of the shunt can complicate catheter manipulation. This study aimed to clarify the morphological features of gastrorenal shunts relevant to BRTO using three-dimensional computed tomography (3DCT)-portography and to evaluate its concordance with intraoperative venography. Methods Patients who underwent BRTO between January 2017 and October 2024 were included. Preoperative dynamic contrast-enhanced CT was used to reconstruct 3DCT-portography images. The morphological evaluation focused on stenosis and angulation of the shunt. Measurements compared between 3DCT-portography and intraoperative venography included the distance from the left renal vein to the stenosis, vertebral level of the stenosis, stenotic diameter, common trunk diameter with the left adrenal vein, and stenosis rate. Results Nineteen patients were included. All showed a stenosis just above the common trunk with the left adrenal vein (17 ± 4.7 mm from the left renal vein). A marked dorsal angulation (62.9 ± 18.4°) was observed cranial to the stenosis. No significant differences were found between the two modalities in most measurements, indicating high concordance. However, a significant difference was noted at the vertebral level (p = 0.0022), with 3DCT-portography showing a lower position. Conclusion : Consistent stenosis was observed just above the common trunk, with a dorsal angulation cranial to it. The gastrorenal shunt anatomy was effectively visualized using 3DCT-portography, which showed good correlation with the intraoperative venography findings.