Cross-sectional imaging now substitutes for physical diagnosis in most emergency rooms. It is far more sensitive and specific for identifying early structural or anatomic anomalies than even the most astute clinician.

Therefore, most patients with varied non-descript abdominal symptoms make their first stop in the computed tomography (CT) scanner. Although both positive and a negative CTs are important, they come with a potential long term cost: radiation exposure.

In a recently published study, Smith-Bindman et al estimated that 1 in 1,000 patients undergoing a single non-contrast CT scan incur an increased risk of a radiation induced cancer.1

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Of course, the value of a CT scan in treating an identified abnormality cannot be overstated. In the case of kidney stones, size, location, anatomy, and density are all critical components in determining proper therapy. Indeed, these are so important to the treating urologist that CT scans have become the de facto standard, particularly for patients presenting with flank pain. 

In a recent study using national representative data Hyams et al noted that from 2000 to 2008 there was a greater than 100% increase in the use of CT scans in the ER for the evaluation of flank pain with a simultaneous decrease in KUBs and a low but stable use of renal ultrasound. During the same time period, the proportion of patients with flank pain ultimately diagnosed with stones remained stable (20%).2

As physicians and health systems are increasingly required to manage risk, several investigators recently published studies showing that kidney stone characteristics (size, locations, number, density) are equally well determined using a low-dose CT protocol compared with standard protocols. Radiation dose is calculated based on body mass index, scans are performed at 2-3 mm cuts, and 3-D reconstructions are made. Average radiation doses were decreased by approximately 75% without compromising the data obtained.3

Equal information with less risk seems like a no brainer, but who owns the implementation of such change? Urologists? Nephrologists? Radiologists? Emergency physicians?

I vote for all the above. While health systems are bringing stakeholders together to develop best practices, the tempo is slow and ownership weak. Accountable care is not only about economics, and it starts with physicians understanding risk, making tradeoffs, and building better care processes—something from which we can all benefit.


  1. Smith-Bindeman R, et al. Arch Intern Med 2009;169:2078-2086.
  2. Hyams ES, et al. J Urol 2011;186:2270-2274.
  3. Hyams ES, Shah O. Curr Urol Rep 2010;11:80-86.