Semiautomatic volume measure of kidney vascular territories on CT angiography to plan aortic aneurysm repair in patients with horseshoe kidney.

Surgical repair of abdominal aortic aneurism (AAA) with horseshoe kidney (HK) is challenging because of several accessory renal arteries (RAs), variable in number, branches, and vascular territories, with subsequent variable renal damage. The identification of RAs and vascular territories could contribute to surgical planning. We developed a semiautomatic presurgical computed tomography angiography (CTA)-based model to measure the renal volume of each RA, validated on postsurgical CTA in patients with HK treated for AAA. Renal parenchyma volume was extracted on both CTAs (Vol_Tot_pre and Vol_Tot_post) after labeling RAs ostia and vascular endpoints by two observers using a semiautomatic model by assigning each renal voxel to the closest vascular ending, obtaining volumes for each vascular territory. Number of RAs number was 4.0 ± 1.4 (mean ± standard deviation (SD)), Vol_Tot_pre 360 ± 76.5 cm³; kidney volume loss at surgery (KVLS) (Vol_Tot_pre minus Vol_Tot_post) 51.9 ± 35.4 cm³; percentage of kidney loss 15.2 ± 11.6%. KVLS and predicted kidney volume loss on preoperative CTA (PKVL) were strongly correlated (r = 0.93; p = 0.023). Interobserver agreement was good (mean bias = 0.000001 ± 1.96 SD of 19.1 cm³). Presurgical semiautomatic segmentation of vascular territories in patients with HK and AAA is feasible. RELEVANCE STATEMENT: This software allowed the preoperative calculation of renal volume perfused by each renal artery in the challenging association of the horseshoe kidney and abdominal aortic aneurism. It helps to determine the feasibility of surgical resection of arteries, thereby improving surgical planning and reducing the risk of postoperative renal function deterioration. KEY POINTS: The association between horseshoe kidney and abdominal aortic aneurism is a challenging condition that may require renal vascular resection. A semiautomatic model measures renal volume perfused by each artery on preoperative computed tomography angiography with high accuracy. Customized use of this tool could improve surgical management by determining which arteries can be safely resected during surgery.