Objectives of the evaluation are mainly:<ref>{{cite web|url=https://emedicine.medscape.com/article/381993-overview|title=Urinary Calculi Imaging|author=J Kevin Smith, Mark E Lockhart, Nicole W Berland and Philip J Kenney|website=Medscape|date=2015-10-27}}</ref>
*Presence of stones within the urinary tract
*Also compare to previous CTs if there is any passage of previous stones.
*Complications such as hydronephrosis (''See: [[Hydronephrosis]]'')
===Further evaluation in presence of stones===
*Measure the size of stones. Proper sizing of a stone is important at around 5 mm and above, since smaller stones generally pass spontaneously.<ref group="notes">Ureteric stones less than 5 mm in diameter pass spontaneously in up to 98% of cases, while those measuring 5 to 10 in diameter pass spontaneously in less than 53% of cases.<br> - {{cite journal|last=Gettman|first=MT|last2=Segura|first2=JW|title=Management of ureteric stones: Issues and controversies|journal=British Journal of Urology International|volume=95|issue=Supplement 2|pages=85–93|year=2005|pmid=15720341|doi=10.1111/j.1464-410X.2005.05206.x}}</ref> Sizing of larger stones is also important in order to decide which treatment to choose.<ref group="notes">Small proximal ureteral calculi of less than 10 mm are best treated with shock wave lithotripsy and ureteroscopy, while those larger than 10 mm are best treated with flexible ureteroscopy combined with holmium laser lithotripsy.
<br> - {{cite web|url=https://www.uptodate.com/contents/management-of-ureteral-calculi|title=Management of ureteral calculi|author=Glenn M Preminger, Section Editors:Stanley Goldfarb, Michael P O'Leary. Deputy Editor:Albert Q Lam|date=2018-01-19|website=UpToDate}}</ref>
*Confirm any stone passage*Assess the stone burdenin the kidneys
<gallery mode=packed heights=230>
File:3mmstone.png|[[Transverse plane|Axial]] CT without contrast, showing a 3-mm stone (marked by an arrow) in the left proximal ureter