Of the manuscript: predictive value of renal parenchyma and pelvic urine density on preoperative non-contrast CT in systemic inflammatory response syndrome (SIRS) after semi-rigid ureteroscopy.

To evaluate the predictive value of preoperative NCCT (Non-Contrast Computed Tomography) measured renal parenchyma and pelvic urine densities for the development of systemic inflammatory response syndrome (SIRS) following URS. 1262 patients underwent semi-rigid URS due to ureterolithiasis between January 2008 and August 2023 were screened and 286 patients were included. Patient demographics and NCCT findings (stone size, location, density, hydronephrosis, renal parenchymal density, pelvic urine density) were collected retrospectively. Patients were categorized into two groups based on SIRS development after URS. Pelvic urine and parenchyma densities of the obstructed kidney were compared. A multivariate logistic regression analysis was performed to identify independent predictors of SIRS. The median obstructed kidney cortex mean density was significantly lower in the SIRS (+) group compared to the SIRS (-) group (26.67 [22.33-29.50] vs. 33.33 [27.24-37.75]). Obstructed kidney medulla mean density was also significantly lower in patients with SIRS (24.00 [22.33-27.50] vs. 31.50 [26.24-36.75], p = 0.001). Pelvic urine density was significantly higher in the SIRS-positive group. Stone density (OR = 1.35, % 95 CI: 1.09-1.67, p = 0.006), proximal ureteral location (OR = 5.21, % 95 CI: 1.84-14.7, p = 0.002), cortex mean density (OR = 0.91, % 95 CI: 0.87-0.95, p = 0.001) and pelvic urine density (OR = 1.07, % 95 CI: 1.02-1.12, p = 0.010) were stated as significant predictors. Renal parenchyma and pelvic urine density on pre-operative NCCT can predict SIRS after semi-rigid URS.