Ultrasonography Versus CT for Suspected Nephrolithiasis
The Article: Ultrasonography versus Computed Tomography for Suspected Nephrolithiasis. The New Engl J Med. 2014 Sep 18.
The Idea: Which initial imaging modality, ultrasound vs. CT, is better for patients with suspected nephrolithiasis?
The Study: 2759 patients ages 18-76 with suspected nephrolithiasis by an attending physician were randomized to initial imaging study of POC ultrasound by trained EM physician, ultrasound by radiologist, or abdominal CT. Primary endpoints were 30 day incidence of high risk diagnosis with complications related to missed/delayed diagnosis, and cumulative radiation.
The Findings: CT was a more sensitive study in detecting nephrolithiasis but there was no significant difference between treatment groups with regards to poor outcomes at 30 days, and the two ultrasound treatment groups had significantly lower cumulative radiation exposure.
The Takeaway: Ultrasound seems like a good first diagnostic study in patients with classic signs of nephrolithiasis. A CT scan is a more sensitive study but didn’t change patient outcomes. We need to be careful though: patients who were sick, extremes of age, or had another more likely diagnosis than nephrolithiasis were excluded from this study.