O2193: Scanning for Safety: A Comparison of Ultra-Low Dose CT and Multi-View Chest X-Ray for the Diagnosis of Pediatric Foreign Body Aspiration

Background: Diagnostic evaluation of suspected foreign body aspiration (FBA) has traditionally included multiple-view plain radiographs of the chest (CXR). However, CXR has limited sensitivity and specificity for radiolucent objects. This limitation results in repeat imaging, missed diagnoses, and negative bronchoscopies. Ultra-low dose (ULDCT) and low-dose CT (LDCT) have emerged as alternative imaging modalities with potentially greater diagnostic accuracy, but questions remain regarding radiation exposure and costs. The purpose of this study was to compare the overall safety, efficacy, and resource utilization of reduced-dose CT and CXR in children presenting with suspected FBA.

Methods: A single center retrospective chart review was conducted for patients ≤17 years old presenting between 01/01/2018 and 07/31/2024 with concern for FBA. Clinical datapoints included demographics, clinical history, radiographic, and operative findings. CTs were categorized as ULDCT ( < 0.3–0.5 mGy, depending on patient weight), LDCT ( < 1 mGy), or standard-dose (SDCT, ≥1 mGy) based on reported CTDIVol. Estimated effective doses and total variable costs per patient encounter were compared between imaging modalities.

Results: 330 patients were evaluated, and 379 CXRs and 158 CTs were reviewed for FBA. 132 patients ultimately received bronchoscopy, and the nontherapeutic rate ranged from 0% in patients evaluated with ULDCT only, LDCT only, and combination ULDCT plus CXR to 21% (n=18) in patients evaluated with CXR only. The sensitivity and specificity of ULDCT for lower airway foreign bodies was 100.00% and 100.00%. When considering all airway foreign bodies through the nasopharynx, the sensitivity and specificity of ULDCT was 87.50% and 100.00%. One flat, paper-like pharyngeal foreign body was missed on ULDCT as the field of view terminated at the level of the thoracic inlet. Comparatively, sensitivity and specificity were 76.19% and 83.15% for two-view CXR and 81.82% and 66.67% for four-view CXR. The sensitivity of two-view CXR after excluding patients with radiopaque airway foreign bodies was 50.00%. Eight missed lower airway foreign bodies were identified after initial evaluation with CXR only. The difference in mean effective dose between ULDCT and four-view CXR was 0.18 mSv (p < 0.001). Among patients without operative needs, median total variable cost did not differ based on initial evaluation with CXR ($576.20, SD $965.90) or CT ($514.22, SD $216.73; p=0.213).

Conclusion: ULDCT showed greater sensitivity and specificity FBA than CXR and can be delivered without a clinically significant increase in radiation exposure or hospital expenditure. Use of this highly accurate diagnostic tool can support patient safety initiatives, including efforts to reduce missed diagnoses and unnecessary airway manipulation in potentially complicated pulmonary patients. Our data support routine use of ULDCT in patients suspected of aspirating radiolucent foreign bodies.