Investigation of choice in small renal calculi:

Ans: a) Low dose non enhanced CT Low dose non enhanced CT scans can image renal stones better without much sacrifice in the quality of scanVirtually all stones (including uric acid stones) are radio-opaque on CT, except for stones associated with protease inhibitors used for treating HIV (Indinavir)Even calculi of sub mm size can be easily identified.Most common sites of calculi impaction are:Ureteropelvic junction - 35%Mid ureter - 7%Distal ureter - 33%UV junction -18%