Beyond the Abstract - Radiological imaging of patients with suspected urinary tract stones: National trends, diagnoses, and predictors, by Ralph Wang, MD, RDMS

BERKELEY, CA ( - Our study investigated the effect of CT utilization for emergency department patients presenting with suspected nephrolithiasis.

Using the NHAMCS database of United States emergency departments, we showed that over a time period of 1996 to 2007, CT utilization has increased 10-fold. This finding in itself is not surprising, as several recent studies report that CT utilization has increased drastically in the emergency department since the mid-1990s for a number of different complaints (such as headache, abdominal pain, and traumatic injury) – with a concomitant increase in cost to the health care system. It is believed that the increased utilization of CT has been driven by its excellent accuracy, availability, and perhaps by medico-legal and financial factors as well.

However, there is a paucity of evidence to address whether this increased utilization of CT scan has led to improved patient outcomes. We have found that as CT utilization has increased from 4% to 43% in patients with suspected nephrolithiasis over the years of 1996-2007, the proportion of patients receiving the diagnosis of nephrolithiasis was virtually unchanged. Similarly, the proportion of patients who were admitted to the hospital was unchanged as well. Finally, we also found no difference in the proportion of patients receiving an alternate diagnosis (inflammatory or infectious) to explain their flank pain.

These findings suggest that the increased utilization of CT scans in patients with suspected urolithiasis may not have had a significant effect on the diagnosis or management of urolithiasis. While our publication has limitations (some inherent in our use of the NHMACS database), we believe that this study adds to the growing literature suggesting that although CT scan is the most accurate study for the detection of nephrolithasis, in light of its associated radiation exposure and increased cost, it may not be the best study. We note with interest the recent European Association of Urology 2010 policy statement supporting ultrasound as the “primary diagnostic procedure for patients with renal stone disease.”


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Ralph Wang, MD as part of Beyond the Abstract on This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.


Radiological imaging of patients with suspected urinary tract stones: National trends, diagnoses, and predictors - Abstract Stone Disease Section

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