This 75 y/o female with renal insufficiency was referred to CT for evaluation of abdominal pain. Selected images from her non-contrast enhanced abdomino-pelvic CT shown above demonstrate bilateral ureteral stones. There is mild dilation of the collecting systems bilaterally. There is renal cortical atrophy on the left, however there is some perinephric edema consistent with obstruction. Bilateral ureteral stone extraction led to normalization of renal function.