With the increased availability of cervical spine computed tomography imaging, it is imperative for radiologists to consider their imaging decisions based on the impact the test will have on patients and the health care costs incurred, while also minimizing radiation exposure, especially in younger patients, according to a study by Shadi Asadollahi, MD, of MetroHealth Medical Center, and colleagues, published in Radiology.
The study evaluated the implementation and effectiveness of the National Emergency X-Radiography Utilization Study (NEXUS) criteria and the Canadian C-Spine Rule (CCR) across health care settings and their impact on imaging rates, clinical efficiency, health care costs, and radiation exposure.
Understanding Why the Number of Cervical Spine CTs Remains High
In this review, the researchers examined why cervical spine CT utilization remains high in emergency rooms despite more than two decades of validated clinical decision support tools, including NEXUS criteria and CCR. Although both tools were explicitly designed to reduce unnecessary imaging while maintaining high sensitivity for clinically significant cervical spine injury, their real-world impact on imaging volumes has been modest. The study makes clear that persistent high CT use is driven not by a lack of evidence, but by structural, clinical, and cultural factors that ultimately shift the imaging burden downstream to radiology.
At the population level, blunt trauma presentations are extremely common, with tens of millions of emergency room visits annually, while the prevalence of positive cervical spine CT findings is consistently low—often only between 1% and 4%, and even lower in asymptomatic patients. Despite this low diagnostic yield, CT remains the dominant imaging modality, reinforced by American College of Radiology recommendations that favor CT when decision-rule criteria are met. As a result, radiologists are tasked with interpreting a very high volume of trauma CT examinations that overwhelmingly demonstrate no acute injury.
The review emphasizes that a substantial proportion of patients undergoing cervical spine CT are not ideal candidates for the application of NEXUS or CCR. For example, patients who are intoxicated, sedated, obtunded, cognitively impaired, or polytraumatized cannot be reliably assessed using these rules, yet they represent a large share of trauma-imaging volume. From the radiologist perspective, this translates into routine interpretation of scans ordered under conditions of clinical uncertainty, often with minimal opportunity for imaging avoidance once the study has been requested.
Limited or unclear clinical documentation further compounds this issue. The researchers note that radiologists frequently struggle to identify the specific clinical justification for imaging within the electronic medical record, even when NEXUS or CCR are ostensibly guiding care. Mechanism of injury details, neurologic findings, or which elements of a decision rule were met may be absent, delayed, or buried in templated documentation. This lack of context diminishes the radiologist's ability to tailor interpretation and reinforces a defensive, exhaustive reading approach, increasing cognitive load and interpretive fatigue in a setting already dominated by high-throughput trauma imaging.
Avoiding Unnecessary Radiation Exposure in Younger Patients
Radiation exposure is another major concern highlighted in the study, particularly in younger patients. Cervical spine CT delivers a dose of approximately 2 to 5 mSv, with disproportionate exposure to the thyroid gland. The review summarizes evidence linking these doses to increased lifetime cancer risk, especially in pediatric and young adult patients, whose tissues are more radiosensitive and who have longer remaining life expectancy.
While decision rules aim to limit unnecessary imaging, their emphasis on sensitivity over specificity—especially in pediatric populations—can paradoxically increase imaging rates. For radiologists, this creates tension between diagnostic thoroughness and long-term patient safety, without meaningful control over upstream ordering behavior.
The disconnect between emergency room decision-making and downstream imaging burden is a central theme throughout the study. Medicolegal concerns, fear of missed injury, and local practice culture often lead clinicians to favor imaging even when decision rules suggest low risk.
The CCR, while more effective than NEXUS in reducing imaging in controlled studies, is perceived as more complex and time-consuming than NEXUS, limiting consistent adoption. As a result, actual reductions in CT utilization frequently fall short of what validation studies predict, leaving radiologists to absorb the cumulative workload.
Addressing the Challenges of Over-Reliance on NEXUS and CCR
Overall, the study findings underscore that cervical spine CT volumes remain high not because decision rules are ineffective, but because they are unevenly applied within complex clinical environments. Radiologists bear the downstream consequences: high-volume, low-yield interpretation; limited clinical context; radiation stewardship concerns; and little influence over imaging appropriateness once studies are ordered.
Addressing these challenges, the researchers suggest, will require system-level alignment between emergency medicine workflows, documentation practices, and radiology's role in imaging stewardship, rather than further refinement of decision rules alone.
The study researchers reported no funding or conflicts of interest.
Source: Radiology
