Original Contribution
Prevalence of incidental findings in trauma patients detected by computed tomography imaging

https://doi.org/10.1016/j.ajem.2008.03.025Get rights and content

Abstract

Study Objective

The primary intention of spiral computed tomography (SCT) in trauma patients is to identify significant injuries. However, unanticipated information is often discovered. We hypothesize that SCT often identifies clinically significant incidental findings in trauma patients.

Methods

This was a retrospective protocol chart review of consecutive adult trauma patients seen at a level I trauma center. A complete SCT was defined as computed tomography imaging of the head, cervical spine, chest, abdomen, and pelvis, thoracic, and lumbar spine. Incidental findings were classified into 2 categories: type 1, which requires urgent evaluation, and type 2, which requires informing the patient but does not mandate urgent follow-up.

Results

We reviewed 3246 patient charts and 3092 met inclusion criteria. Type 1 findings were reported in 990 (32.0%; 95% confidence interval [CI], 30.4%-33.7%) patients. Type 2 findings were found in 1274 (41.2%; 95% CI, 39.5%-42.9%) patients. Female sex (odds ratio, 1.38; 95% CI, 1.16-1.65) and older age (odds ratio, 2.61; 95% CI, 2.33-2.93) were independently associated with a higher prevalence of type 1 findings. There were 631 incidental findings concerning for neoplasm, which included 196 pulmonary nodules, 99 liver, 36 renal, 23 brain, and 11 breast masses.

Conclusions

A significant number of trauma patients evaluated with SCT are diagnosed with potentially serious incidental findings. For long-term care and medicolegal concerns, physicians need to inform patients of these incidental findings and the need for further evaluation.

Introduction

Strong recommendations and availability have increased the use of spiral computed tomography (SCT) in the initial evaluation of trauma patients [1], [2], [3], [4]. The liberal use of SCT has stirred debate as to the added benefit relative to the risk of radiation exposure and inappropriate use of limited resources [1].

Salim et al [1] reported that findings on SCT led to a change in treatment in nearly 19% of trauma patients [1]. However, only 51 (5.1%) of these patients had abnormal computed tomography (CT) studies that resulted in treatment modifications such as earlier operative intervention. The remaining 138 (13.8%) trauma patients had normal CT studies. Their treatment changes included earlier emergency department (ED) discharges and clearance for operative repairs by other surgical services. Our review of the literature does not provide conclusive evidence to either advocate or discourage whole-body CT scans in the ED evaluation of trauma patients. The potential benefits of liberal SCT imaging in trauma patients must be weighed against the risks of radiation exposure and contrast-induced nephropathy [5], [6]. The estimated lifetime mortality risk attributable to cancer from a whole-body CT examinations is 0.08%, with the potential for rates as great as almost 2% with annual scans [7], [8], [9], [10]. The estimated lifetime cancer risks for CT coronary and aorta angiography alone were reported to be as high as 0.87% for a 20-year-old woman and 0.15% for a 20-year-old man [7].

The presence of incidental findings on CT or SCT has been documented by several studies [11], [12], [13], [14], [15], [16], [17], [18]. A recent trauma registry review reported 289 incidental findings on SCT in 848 admitted trauma patients [11]. Incidental abnormalities were discovered on 30 of 3000 brain CT scans done for trauma, and 445 of 1192 nontraumatized patients undergoing whole-body CT had findings that required recommendation for follow-up [19], [20]. In CT angiograms of 175 potential living related kidney donors, 71 (40.6%) had extrarenal findings and 18 (10.3%) were considered of high clinical importance [12].

Critics have stated that the discovery of these incidental findings on SCT in trauma patients may further burden the health care system with additional workups for inconsequential abnormalities such as adrenal “incidentalomas” [12], [13], [18], [21]. However, a recent study looked at thyroid nodules found incidentally on CT scan. Of the 230 patients who were found to have thyroid nodules, 118 underwent biopsy and 22% were found to be malignant [22]. It has also been reported that 4% of incidental findings found on CT aortic angiograms and 29% of incidentally discovered adrenal masses greater than 3 cm in diameter were determined to be malignant [15], [23].

Although the primary intention of the SCT in trauma patients is to identify injuries, unanticipated information is often discovered in the course of this testing. Emergency physicians and trauma surgeons must be cognizant of these potentially serious findings in both patients requiring admission and those discharged from the ED.

The objective of this study is to determine the prevalence of incidental findings in consecutive major trauma patients who underwent a complete SCT as part of their trauma evaluation.

Section snippets

Study design

This was a retrospective protocol chart review of all major trauma patients who received a complete SCT, including those admitted and discharged. A complete SCT was defined as imaging of the head, cervical spine, chest, abdomen, and pelvis, thoracic, and lumbar spine. Our institutional review board found this study exempt from human subjects review.

Results

The ED database query resulted in 3246 patient who underwent SCT as part of their ED evaluation. We reviewed all of these patients' records, and 3092 met the inclusion criteria. One hundred fifty-four patients were excluded from the analysis for the following reasons: 97 patients did not undergo a complete SCT, 49 patients had no CT imaging performed in the ED, and 8 patients were younger than 15 years. The ages of 163 patients were not recorded in the electronic medical record, and these

Discussion

The use of SCT in the initial management of trauma patients has become a recommended practice at many trauma centers [1], [2], [3], [4]. This study found that more than 50% of trauma patients had nontrauma-related incidental findings on their imaging studies. Nearly a third of patients had findings on SCT that have the potential to cause significant morbidity if not further evaluated. In a recent review of an inpatient trauma registry, 144 clinically significant incidental findings were found

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