Would you obtain an abdominal non-contrast CT study for further routine evaluation of stone burden in a patient with recurrent nephrolithiasis who recently completed an abdominal iodinated contrast CT study for non-stone purposes?  

Often, there is no pre-contrast imaging, and stones cannot be counted well once contrast enters the kidneys. So, unless there was a pre-contrast phase, the contrast CT cannot be considered adequate for determining stone burden and new stone activity. So if either is at issue, I would obtain a non-co...

My decision would depend upon how well the existing stones were visualized on the contrast CT study. If the stones were well enough visualized to detect a future change in size or number, I would not do a non-contrast CT scan for approximately one year. However, if precise.stone evaluation was obscu...