Inter-Observer Delineation Differences in Esophageal Cancer GTV on MR, CT, and PET/CT Protokol šečerov Ermenc 28dec19

NCT07416825 | Completed

• 2 other identifiers: ERID-KSOPKR-0005/2020ARRS / ID: 33071
• Study Type: interventional
• Target: 23
• Locations: 1 country
• Sites: 1

Brief Summary

Esophageal cancer radiotherapy requires accurate delineation of the gross tumor volume (GTV) to ensure adequate tumor coverage and to minimize radiation dose to surrounding organs at risk. Computed tomography (CT) is routinely used for target delineation, while positron emission tomography-computed tomography (PET/CT) may provide additional functional information. However, uncertainty in tumor boundaries and inter-observer variation remain clinically relevant issues. Magnetic resonance imaging (MRI) provides improved soft tissue contrast and diffusion-weighted imaging (DWI) information, which may improve visualization of esophageal tumors. This study evaluates whether MRI-based imaging, alone or fused with CT or PET/CT, reduces inter-observer variation in GTV delineation compared with standard CT and PET/CT-based delineation. A total of 21 patients with locally advanced esophageal cancer undergoing standard radiotherapy preparation will undergo MRI simulation in addition to routine CT and PET/CT simulation. Five experienced radiation oncologists will independently delineate the primary tumor GTV on CT, MRI, PET/CT, CT-MRI fusion, and PET/CT-MRI fusion datasets. Inter-observer variation will be assessed using conformity indices and spatial analysis tools.

Conditions

Esophageal Cancer; Esophageal Carcinoma

Keywords

Radiotherapy Planning; Target Volume Delineation

Outcome Measures

Primary Outcomes (3)

• Volumetric Conformity Index (VCI) Compared With Reference Contour

  Volumetric conformity index (VCI) will be calculated using the Contour Analysis Tool (CAT) by comparing each observer's gross tumor volume (GTV) contour to a reference contour generated using the STAPLE algorithm. VCI is defined as the ratio of intersection volume to union volume and ranges from 0 to 1. The outcome will be reported as mean VCI for each imaging dataset.

  Up to 14 days after completion of contouring for each imaging dataset

• Inter-observer Variability in GTV Delineation (Generalized Conformity Index, CIgen)

  Inter-observer agreement in gross tumor volume (GTV) delineation will be assessed using the generalized conformity index (CIgen) calculated using the Contour Analysis Tool (CAT). CIgen is defined as the ratio of the sum of pairwise intersections to the sum of pairwise unions of all observers' contours and ranges from 0 to 1. The outcome will be reported as CIgen for each imaging dataset.

  Up to 14 days after completion of contouring for each imaging dataset

• Image Quality Rating (5-point Likert Scale)

  Observers will rate the image quality of each imaging dataset (CT, MRI, PET/CT, CT-MRI fusion, PET/CT-MRI fusion) using a 5-point Likert scale (1 = very poor, 5 = excellent). The outcome will be reported as mean image quality score.

  During contouring sessions (up to 14 days per imaging dataset)

Secondary Outcomes (4)

• Planar Conformity Index (PCI) Compared With Reference Contour

  Up to 14 days after completion of contouring for each imaging dataset

• Spatial Inter-delineation Distance (IDD) Between Observer Contours and Reference Contour

  Up to 14 days after completion of contouring for each imaging dataset

• Contouring Time

  During contouring sessions (up to 14 days per imaging dataset)

• Perceived Difficulty of Delineation (5-point Likert Scale)

  During contouring sessions (up to 14 days per imaging dataset)

Study Arms (5)

CT

ACTIVE COMPARATOR

Standard planning CT for GTV delineation.

Diagnostic Test: Computed Tomography (CT)

MRI

EXPERIMENTAL

MRI simulation for GTV delineation.

Diagnostic Test: Magnetic Resonance Imaging (MRI)

PET/CT

ACTIVE COMPARATOR

PET/CT simulation for GTV delineation.

Diagnostic Test: Positron Emission Tomography/Computed Tomography (PET/CT)

CT + MRI Fusion

EXPERIMENTAL

CT images fused with MRI for GTV delineation.

Diagnostic Test: CT-MRI Image Fusion

PET/CT + MRI Fusion

EXPERIMENTAL

PET/CT images fused with MRI for GTV delineation.

Diagnostic Test: PET/CT-MRI Image Fusion

Interventions

Computed Tomography (CT) DIAGNOSTIC_TEST

CT imaging performed as part of standard radiotherapy simulation and planning for esophageal cancer. CT datasets are used for gross tumor volume (GTV) delineation.

CT

Magnetic Resonance Imaging (MRI) DIAGNOSTIC_TEST

MRI performed on a radiotherapy MRI simulator (T2-weighted sequences and diffusion-weighted imaging) using the same immobilization as CT/PET-CT simulation. MRI datasets are used for GTV delineation.

MRI

Positron Emission Tomography/Computed Tomography (PET/CT) DIAGNOSTIC_TEST

FDG PET/CT imaging performed as part of standard radiotherapy preparation. PET/CT datasets are used for GTV delineation, with contouring performed on CT and adjusted using PET information when appropriate.

PET/CT

CT-MRI Image Fusion DIAGNOSTIC_TEST

Image registration and fusion of MRI with CT datasets for radiotherapy planning. Fused CT-MRI images are used for GTV delineation to evaluate the effect of MRI information on contouring variability.

CT + MRI Fusion

PET/CT-MRI Image Fusion DIAGNOSTIC_TEST

Image registration and fusion of MRI with PET/CT datasets for radiotherapy planning. Fused PET/CT-MRI images are used for GTV delineation to evaluate inter-observer variation compared with standard PET/CT-based contouring.

PET/CT + MRI Fusion

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age ≥18 years
• Locally advanced esophageal cancer (T1b-4b, N0-N+, M0)
• Siewert type I or II for distal esophageal tumors
• Planned preoperative or definitive chemoradiotherapy
• Written informed consent for participation in the study
• No contraindications for MRI

You may not qualify if:

• Implanted metallic objects with magnetic properties or electromagnetic devices without MRI compatibility confirmation
• Physical or psychological conditions preventing informed consent

Sponsors & Collaborators

• Institute of Oncology Ljubljana: lead

Study Sites (1)

Institute of Oncology Ljubljana

Ljubljana, 1000, Slovenia

Location

MeSH Terms

Conditions

Esophageal Neoplasms

Interventions

Tomography, X-Ray Computed; Magnetic Resonance Imaging; Positron-Emission Tomography; Positron Emission Tomography Computed Tomography

Condition Hierarchy (Ancestors)

Gastrointestinal Neoplasms; Digestive System Neoplasms; Neoplasms by Site; Neoplasms; Head and Neck Neoplasms; Digestive System Diseases; Esophageal Diseases; Gastrointestinal Diseases

Intervention Hierarchy (Ancestors)

Image Interpretation, Computer-Assisted; Diagnostic Imaging; Diagnostic Techniques and Procedures; Diagnosis; Radiographic Image Enhancement; Image Enhancement; Photography; Radiography; Tomography, X-Ray; Tomography; Tomography, Emission-Computed; Radionuclide Imaging; Diagnostic Techniques, Radioisotope; Multimodal Imaging

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: Imaging datasets and observer identities are anonymized. Delineations are performed independently.
• Purpose: DIAGNOSTIC
• Intervention Model: FACTORIAL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Participants undergo multiple imaging modalities (CT, PET/CT, MRI) for radiotherapy planning. Target volume delineations are compared across modalities within the same participants.

Study Record Dates

• First Submitted: February 6, 2026
• First Posted: February 18, 2026
• Study Start: January 1, 2020
• Primary Completion: June 30, 2021
• Study Completion: June 30, 2021
• Last Updated: February 18, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will not share

Locations

SL (1)