Obstructing peritransplant fluid collection

Longitudinal ultrasound of a transplant kidney (A) shows mild hydronephrosis in the setting of a fluid collection inferior and medial (arrow). Ultrasound image of the full bladder (B, *); the collection (arrowhead) is between the kidney and bladder, compressing the ureter. Noncontrast computed tomography (C) confirms the ultrasound findings (bladder, *; collection, dashed arrow). In a patient with these findings, obstruction due to the fluid collection can be confirmed only after the bladder is emptied.