Gastrointestinal Lesions
Conditions
Keywords
Small Gastrointestinal Lesions
Brief summary
This comparative matched-cohort study aims to evaluate the diagnostic performance of contrast-enhanced photon-counting computed tomography (PCCT) for detecting small gastrointestinal lesions compared with energy-integrating detector dual-energy computed tomography (DECT). The study includes a prospectively enrolled PCCT cohort and a retrospectively identified DECT cohort. Endoscopy with histopathology serves as the reference standard. Primary evaluation focuses on lesion detection, with additional assessment of lesion characterization, image quality, quantitative imaging parameters, and interobserver agreement.
Interventions
DIAGNOSTIC_TESTContrast-Enhanced Photon-Counting Computed Tomography
Contrast-enhanced abdominal photon-counting computed tomography performed for the detection and characterization of small gastrointestinal lesions.
DIAGNOSTIC_TESTContrast-Enhanced Energy-Integrating Detector Dual-Energy Computed Tomography
Contrast-enhanced abdominal energy-integrating detector dual-energy computed tomography performed for comparison of diagnostic performance in detecting and characterizing small gastrointestinal lesions.
Sponsors
The Second Affiliated Hospital of Chongqing Medical University
Study design
Observational model
COHORT
Time perspective
OTHER
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
1. Adults aged 18-80 years. 2. Patients undergoing contrast-enhanced abdominal CT (photon-counting CT or energy-integrating detector dual-energy CT). 3. At least one endoscopically detected or clinically suspected small gastrointestinal lesion. 4. Lesions confirmed or suspected on endoscopy, pathology, or follow-up imaging. 5. Lesions characterized as mucosal thickening or nodular lesions within predefined size criteria (≤2 cm).
Exclusion criteria
1. Prior gastrointestinal surgery affecting target evaluation region. 2. Poor or nondiagnostic CT image quality. 3. Incomplete or unavailable endoscopic or histopathological reference standard. 4. Ambiguous lesion localization on endoscopy or imaging. 5. Severe motion artifacts or inadequate bowel distension affecting diagnostic evaluation.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Lesion-Based Detection Rate | During the study period (January 2026 - March 2026) | Lesion-based detection rate of contrast-enhanced photon-counting CT compared with energy-integrating detector dual-energy CT using endoscopy with histopathology, when available, as the reference standard. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Positive Predictive Value of CT-Positive Findings | During the study period (March 2026 to June 2026) | Patient-level positive predictive value (PPV) of CT-positive findings for small gastrointestinal lesions detected on contrast-enhanced photon-counting CT (PCCT) in the prospective implementation cohort. Endoscopy with histopathology, when available, served as the reference standard. |
| Yield of Clinically Actionable Lesions | During the study period (March 2026 to June 2026) | Patient-level yield of clinically actionable small gastrointestinal lesions detected in consecutive patients undergoing routine contrast-enhanced photon-counting CT (PCCT) in clinical practice. Clinically actionable lesions were defined based on endoscopic or histopathological confirmation when available. |
| Lesion-to-Mucosa Attenuation Difference | During the study period (January 2026 - March 2026) | Difference in attenuation between gastrointestinal lesions and adjacent normal mucosa measured on 40-keV virtual monoenergetic images from photon-counting CT. |
| Image Noise | During the study period (January 2026 - March 2026) | Image noise will be defined as the standard deviation of CT attenuation values within a predefined region of interest in the target tissue or reference region. Image noise will be measured separately on photon-counting CT and dual-energy CT images. Lower values indicate lower image noise. |
| Signal-to-Noise Ratio | During the study period (January 2026 - March 2026) | The signal-to-noise ratio will be calculated as the mean CT attenuation value of the target tissue divided by image noise. SNR will be calculated separately for photon-counting CT and dual-energy CT images. Higher values indicate better signal relative to image noise. |
| Contrast-to-Noise Ratio | During the study period (January 2026 - March 2026) | The contrast-to-noise ratio will be calculated as the absolute difference between the mean CT attenuation values of the target tissue and the reference tissue divided by image noise. CNR will be calculated separately for photon-counting CT and dual-energy CT images. Higher values indicate greater contrast relative to image noise. |
| Subjective Image Quality Score | During the study period (January 2026 - March 2026) | Two radiologists, blinded to the clinical, endoscopic, and histopathologic findings, will independently evaluate the image quality of photon-counting CT and dual-energy CT images using a predefined 5-point ordinal scale. Scores range from 1 to 5, with higher scores indicating better subjective image quality. |
| Interobserver Agreement for Lesion Detection | During the study period (January 2026 - June 2026) | Agreement between two radiologists regarding the presence or absence of gastrointestinal lesions on CT images will be assessed using Cohen's kappa coefficient. Kappa values range from -1 to 1, with higher values indicating better interobserver agreement. Agreement will be evaluated separately for photon-counting CT and dual-energy CT. |
| Interobserver Agreement for Lesion Size Measurement | During the study period (January 2026 - June 2026) | Agreement between two radiologists for measurements of the maximal lesion diameter will be assessed using the intraclass correlation coefficient. Intraclass correlation coefficient values range from 0 to 1, with higher values indicating better interobserver agreement. Agreement will be evaluated separately for photon-counting CT and dual-energy CT. |
| Interobserver Agreement for Diagnostic Confidence | During the study period (January 2026 - March 2026) | Agreement between two radiologists for ordinal diagnostic confidence ratings will be assessed using the weighted kappa coefficient. Weighted kappa values range from -1 to 1, with higher values indicating better interobserver agreement. Agreement will be evaluated separately for photon-counting CT and dual-energy CT. |
Countries
China
Outcome results
None listed