Use of intravenous pyelography after noncontrast computed tomography

Axial noncontrast CT showing mild left hydronephrosis and perinephric stranding (A). Coronal noncontrast CT showing the obstructing mid-left ureteral stone (B; arrow). Follow-up IVP scout (C) and 10-minute (D) KUBs showing no stone and normal bilateral kidney function confirming stone passage.