Professional consensus supports the use of ultrasound for initial imaging evaluation of patients presenting in the ED with suspected urinary stone disease (USD). However, as of 2018, only 2% of these patients received ultrasound while some 59% had CT.
So report Stanford researchers who analyzed data in the Nationwide Emergency Department Sample and, in the December edition of JAMA, recommend broad consideration of ultrasound for initial USD workup [1].
After identifying more than 7.5 million unique visits for suspected USD between 2012 and 2018, Nephrologist Calyani Ganesan, MD, and colleagues found most of these visits—89% in 2012, 96% in 2018—ended with patients being sent home straight from the ED.
Further, the proportion of USD visits with no imaging fell from 50.5% in 2012 to 39.1% in 2018.
Of the visits that had either CT or ultrasound, CT use rose markedly—from 48.6% in 2012 to 59.2% in 2018—while ultrasound increased only slightly, from 1.49% to 2.07%.
Ganesan and co-authors acknowledge as a limitation their concentration on the imaging modality associated with an eventual diagnosis of USD. This focus may have obscured circumstances in which clinicians chose an imaging modality before considering USD as a possible diagnosis.
“Even so, CT is the dominant imaging tool being used in ED visits associated with USD,” the authors comment.
4 Reasons to Choose POCUS Over CT for Emergency Kidney Stone Diagnostics
Ganesan and colleagues offer four justifications for elevating point-of-care ultrasound to first-line imaging status over CT in the ED for suspected urinary stone disease:
1. To our knowledge, no studies have documented the superiority of CT in improving USD outcomes or in reducing morbidity;
2. Although CT is highly sensitive for stone detection, the superior sensitivity of CT may not matter for smaller stones that pass without intervention;
3. Use of point-of-care ultrasonography may be associated with shorter wait times in the ED; and
4. Use of ultrasonography limits the exposure of patients with recurrent stone events to repetitive doses of ionizing radiation.
“These imaging trends should encourage the American Urological Association to follow the lead of the European Urological Association and update guidelines that recommend ultrasonography for the initial evaluation of suspected USD,” Ganesan et al. write. “Greater awareness of evidence and updated guidelines may increase adoption of an ultrasonography-first strategy. These changes may reduce radiation exposure to patients and limit healthcare costs.”
‘That CT Is Used Excessively and to Little Gain Comes As No Surprise’
In invited commentary on the study [2], Rebecca Smith-Bindman and colleagues at UC-San Francisco observe that the reviewed cohort probably includes patients for whom CT was appropriate since their diagnosis was something other than urinary stones.
Still, they note, this limitation in study design does not change Ganesan et al’s key findings: Ultrasound imaging for USD is rare, CT use is growing, and increasingly few patients receive a diagnosis based on clinical evaluation and laboratory values alone.
“Most physicians are simply not following the evidence,” Smith-Bindman and co-authors state.
More from Smith-Bindman and colleagues:
That CT is used excessively and to little gain unfortunately comes as no surprise, as lags between evidence and practice are common. A multimodal approach is almost surely necessary to change practice more quickly. Patient advocacy for increased ultrasonography could help move the needle, particularly among patients with urinary stones who undergo repeated imaging, although patients should not be unduly saddled with the duty of making their healthcare safer.”
And then there are the economics. CT suites are often seen as provider profit centers, Smith-Bindman and co-authors point out.
“If there is even a small chance of benefit of CT, the incentives are aligned to perform it,” they write. “And while direct perverse incentives may rarely be present for an individual physician, systems are not incentivized to reduce CT imaging.”
Dave P. has worked in journalism, marketing and public relations for more than 30 years, frequently concentrating on hospitals, healthcare technology and Catholic communications. He has also specialized in fundraising communications, ghostwriting for CEOs of local, national and global charities, nonprofits and foundations.