Comparison of ultra-low-dose versus standard-dose computed tomography for esophageal foreign body detection

ISRCTN	ISRCTN13588740
DOI	https://doi.org/10.1186/ISRCTN13588740
Sponsor	First Affiliated Hospital of Hebei Medical University
Funder	Hebei Province Medical Science Research Key Project

Submission date: 26/03/2026
Registration date: 31/03/2026
Last edited: 30/03/2026

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Digestive System

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Record updated in last year

Plain English summary of protocol

Not provided at time of registration

Contact information

Dr Xing Guan
Public, Scientific, Principal investigator

No. 89 Donggang Road, Yuhua District
Shijiazhuang
050000
China

Phone	+86 (0)15932013616
Email	guanxing_gx2024@126.com

Study information

Primary study design	Interventional
Allocation	Randomized controlled trial
Masking	Blinded (masking used)
Control	Dose comparison
Assignment	Parallel
Purpose	Diagnostic
Scientific title	Prospective comparison of ultra-low-dose versus standard-dose computed tomography for esophageal foreign body detection
Study objectives	This study aimed to address these knowledge gaps by conducting a prospective comparison of ultra-low-dose CT (ULD-CT) and standard-dose CT (SD-CT) for EFB detection.
Ethics approval(s)	Approved 15/04/2025, Ethics Committee of The First Hospital of Hebei Medical University (No. 89 Donggang Road, Yuhua District, Shijiazhuang, 050000, China; +86 (0)311-87156182; 1861123450@163.com), ref: [2025]YS-062
Health condition(s) or problem(s) studied	Patients suspected of swallowing esophageal foreign body (EFB)
Intervention	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 reconstruction. Raw data are reconstructed using 80% adaptive statistical iterative reconstruction blending, followed by DLIR at medium strength. For both protocols, images will be reconstructed at a 0.625-mm slice thickness with a 0.5-mm overlap to enable multiplanar reformations. The scan range will extend from the lower neck (C3 level) through the gastroesophageal junction, with careful positioning to minimize breast tissue inclusion in female patients. Dose reduction features, including organ-based tube current modulation and adaptive collimation, will be enabled for all scans.
Intervention type	Other
Primary outcome measure(s)	Image quality measured using a medical physicist blinded to the protocol assignment. The signal-to-noise ratio (SNR) was calculated as the mean attenuation of the descending aorta divided by the standard deviation of subcutaneous fat. The contrast-to-noise ratio was calculated as the difference in attenuation between aortic blood and paraspinal muscle divided by image noise. To better align with the diagnostic task, additional measurements were performed in paraesophageal fat. Measurements were performed on axial images at three standardized levels (aortic arch, carina, and mid-esophagus) with circular regions of interest (150 mm²) placed consistently using anatomical landmarks. Subjective image quality was independently assessed by two thoracic radiologists with 8 and 12 years of experience. Images were reviewed on diagnostic workstations (window width: 350 HU, window level: 40 HU for soft tissue; window width: 1,500 HU, window level: −600 HU for lung evaluation). Readers scored the following parameters on a 5-point Likert scale: (1) edge definition of the mediastinal structures; (2) image noise; (3) diagnostic confidence for foreign body detection; and (4) overall diagnostic quality. A score ≥3 was considered diagnostically acceptable. Discrepancies between readers were resolved through consensus review, with the consensus score used for analysis. Inter-reader agreement was assessed using weighted kappa statistics. Measured at CT scanning. Radiation dose metrics measured using the scanner-reported volume CT dose index (CTDIvol) and dose-length product. The effective dose (ED) was calculated using age- and sex-specific conversion factors (k = 0.014 mSv·mGy⁻¹·cm⁻¹ for adults; age-adjusted factors for pediatric patients based on International Commission on Radiological Protection recommendations [Publication 103]). Size-specific dose estimates were calculated using patient anteroposterior and lateral dimensions measured at the mid-chest level. Measured at CT scanning.
Key secondary outcome measure(s)
Completion date	25/09/2025

Eligibility

Participant type(s)
Age group	Mixed
Lower age limit	3 Years
Upper age limit	80 Years
Sex	All
Target sample size at registration	180
Total final enrolment	180
Key inclusion criteria	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
Key exclusion criteria	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)
Date of first enrolment	18/01/2024
Date of final enrolment	26/06/2025

Locations

Countries of recruitment

China

Study participating centres

Results and Publications

Individual participant data (IPD) Intention to share	No

Editorial Notes

26/03/2026: Study's existence confirmed by the Ethics Committee of The First Hospital of Hebei Medical University.