Prospective comparison of ultra-low-dose versus standard-dose computed tomography for esophageal foreign body detection
Patients suspected of swallowing esophageal foreign body (EFB)
Patients will be randomized to ULD-CT (100 kV/50 mA, adaptive statistical iterative reconstruction-V 80% + deep learning image reconstruction) or SD-CT (120 kV/200 mA, filtered back projection + adaptive statistical iterative reconstruction-V 30%) groups. Patient randomization is performed using a computer-generated sequence with permuted blocks of varying sizes (4, 6, and 8) stratified by age group (pediatric <18 years vs adult ≥18 years) and the participating center. Allocation concealment is maintained through sealed opaque envelopes opened immediately prior to CT scanning. All image interpreters, endoscopists, and surgeons are blinded to the CT protocol assignment. All examinations are performed on 256-slice multi-detector CT scanners with deep-learning reconstruction capabilities . Patients are positioned supine with their arms elevated above the head when possible. No oral contrast is administered to avoid obscuring foreign bodies or delaying endoscopy. The SD-CT protocol will utilize parameters consistent with routine chest CT at participating institutions: a tube voltage of 120 kV, a reference tube current of 200 mA with automatic tube current modulation (ATCM) enabled, a rotation time of 0.5 seconds, a pitch of 0.992, and collimation of 0.625 mm. Images are reconstructed using filtered back projection with 30% adaptive statistical iterative reconstruction blending, representing the current clinical standard at participating sites. The rationale for 120 kV is based on standard thoracic imaging protocols optimized for general diagnostic purposes. The ULD-CT protocol will employ aggressive dose reduction strategies: a tube voltage of 100 kV, a reference tube current of 50 mA with ATCM (range 10–80 mA), and an identical rotation time and pitch to that of the SD protocol. The 100 kV/50 mA parameters are selected based on preliminary phantom studies demonstrating maintained foreign body conspicuity at these settings when combined with advanced reconstructio
1. Patients aged 3–80 years 2. A history of foreign body ingestion within 6 hours of presentation 3. Symptoms suggestive of esophageal impaction, including dysphagia, odynophagia, chest pain, or hypersalivation 4. Planned endoscopic or surgical evaluation within 12 hours of CT imaging
1. Severe cardiorespiratory instability requiring immediate intervention 2. Pregnancy or a positive pregnancy test 3. A known contrast allergy (for enhanced scans when clinically indicated) 4. Prior esophageal surgery or known esophageal stricture 5. Metallic implants causing substantial artifacts affecting >30% of the esophageal evaluation area 6. Body mass index (BMI) >40 kg/m² (due to potential image quality degradation at ultra-low doses)