The CT image on the left shows a staghorn stone in the left kidney. Staghorn stones are large calculus found in the calyceal system extending into the calyces, which gives them an appearance similar to that of the horns of a stag (deer). There is associated hydronephrosis and hydroureter. On the right side, the hydroureter is caused by another small left ureteric stone seen in the images caudally. A non-contrast CT scan is the best image modality to identify radiodense and non-opaque stones.