Never	<25%	>25%, <50%	Approx. 50%	>50%, <75%	>75%	Always
Nephrostogram
X-Ray KUB
X-Ray KUB and ultrasound
Digital tomosynthesis
Non-contrast CT
Contrast-enhanced CT

PCNL – percutaneous nephrolithotomy; CIRF – clinically insignificant residual fragment; KUB – kidneys ureters and bladder; CT – computed tomography