POCUS-ing Holes in the Standard of Care: Rethinking Routine CT for Flank Pain in the Emergency Department

The widespread use of computed tomography (CT) for suspected nephrolithiasis in the emergency department represents a clear example of diagnostic overutilization. CT has rapidly become the default imaging modality in more than 90% of emergency department evaluations for flank pain. However, this is a classic case of diagnostic overreach: CT rarely changes what we do, while reliably adding harm—radiation exposure, incidental findings, and cost—without improving patient outcomes. Large studies demonstrate that despite a tenfold increase in CT utilization for renal colic between 1996 and 2007, there was no associated improvement in rates of stone diagnosis, detection of alternative serious conditions, or hospital admission. Patients with kidney stone disease incur a median emergency department charge of $3,437. System-level burden exceeds $5 billion annually in the United States. In addition, CT imaging identifies incidental findings in 12.7 - 37.9% of cases, frequently leading to further testing or procedures with limited clinical benefit. In response to these concerns, a multidisciplinary panel representing the American College of Emergency Physicians (ACEP), American College of Radiology (ACR), and American Urological Association (AUA) reviewed 232 studies across 29 clinical scenarios using a modified Delphi process. In contrast to current practices, The panel concluded that CT is appropriate in only 24% of cases, ultrasound in 31%, and no imaging in 45%. CT was considered avoidable in younger patients with prior stone disease and typical presentations, as well as in many middle-aged patients with recurrent symptoms. Ultrasound was strongly recommended as the initial imaging modality for pediatric and pregnant patients. Clinical decision tools such as the STONE score, derived and prospectively validated in more than 1,000 patients, can be used to stratify a patient's probability of Ureteral Stone and aid in deciding what if any imaging should be conducted. Ultrasound-based strategies demonstrate acceptable diagnostic performance. Point-of-care ultrasound has a sensitivity of approximately 70% for detecting hydronephrosis, with specificity improving to 94% when moderate or greater dilation is present. Importantly, ultrasound-first approaches are associated with fewer subsequent CT scans and no increase in missing clinically significant stones, emergency department revisits, or hospitalizations. When ultrasound “misses,” the stones are usually small (<5 mm)—the kind that tend to pass spontaneously. Bottom line: CTs are often low-value care, we should use a more selective, evidence-based ultrasound approach instead for suspected nephrolithiasis. This strategy aligns with current recommendations from the ACEP, ACR, and AUA, reduces unnecessary radiation exposure, decreases ED wait-times, and minimizes downstream harms while preserving diagnostic safety and effectiveness.