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Completed

NCT Number: NCT07748923

Photon-Counting CT for Detection of Small Gastrointestinal Lesions

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.

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Key information

Conditions

Gastrointestinal Lesions

Age range

18 year–80 year

Sex eligibility

All sexes

Study type

Observational

Primary location

The Second Affiliated Hospital of Chongqing Medical University

Chongqing, Chongqing Municipality, 400010, China

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adults aged 18-80 years.
  • Patients undergoing contrast-enhanced abdominal CT (photon-counting CT or energy-integrating detector dual-energy CT).
  • At least one endoscopically detected or clinically suspected small gastrointestinal lesion.
  • Lesions confirmed or suspected on endoscopy, pathology, or follow-up imaging.
  • Lesions characterized as mucosal thickening or nodular lesions within predefined size criteria (≤2 cm).

Exclusion criteria

  • Prior gastrointestinal surgery affecting target evaluation region.
  • Poor or nondiagnostic CT image quality.
  • Incomplete or unavailable endoscopic or histopathological reference standard.
  • Ambiguous lesion localization on endoscopy or imaging.
  • Severe motion artifacts or inadequate bowel distension affecting diagnostic evaluation.

Treatment and study plan

Contrast-Enhanced Photon-Counting Computed Tomography

Diagnostic Test

Contrast-enhanced abdominal photon-counting computed tomography performed for the detection and characterization of small gastrointestinal lesions.

Other names: PCCT

Contrast-Enhanced Energy-Integrating Detector Dual-Energy Computed Tomography

Diagnostic Test

Contrast-enhanced abdominal energy-integrating detector dual-energy computed tomography performed for comparison of diagnostic performance in detecting and characterizing small gastrointestinal lesions.

Other names: DECT

Primary outcomes

  1. Lesion-Based Detection Rate

    Time frame: 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 outcomes

  1. Positive Predictive Value of CT-Positive Findings

    Time frame: 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.

  2. Yield of Clinically Actionable Lesions

    Time frame: 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.

  3. Lesion-to-Mucosa Attenuation Difference

    Time frame: 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.

  4. Image Noise

    Time frame: 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.

  5. Signal-to-Noise Ratio

    Time frame: 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.

  6. Contrast-to-Noise Ratio

    Time frame: 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.

  7. Subjective Image Quality Score

    Time frame: 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.

  8. Interobserver Agreement for Lesion Detection

    Time frame: 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.

  9. Interobserver Agreement for Lesion Size Measurement

    Time frame: 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.

  10. Interobserver Agreement for Diagnostic Confidence

    Time frame: 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.

Sponsors and collaborators

Lead sponsor

The Second Affiliated Hospital of Chongqing Medical University

Other

Registry information

Official study title

Photon-Counting CT for Detection of Small Gastrointestinal Lesions: Comparison With Energy-Integrating Detector Dual-Energy CT and Prospective Clinical Implementation

Acronym: PCCT-GI

Important dates

Study start
2023
Primary completion
2026
Study completion
2026
First posted
Aug 6, 2026
Registry last updated
Aug 10, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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