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Are Gadolinium-Enhanced MR Sequences Needed in Simultaneous 18F-FDG-PET/MRI for Tumor Delineation in Head and Neck
N Pyatigorskaya1,2, R De Laroche3, G Bera4
1From Assistance Publique Hôpitaux de Paris Neuroradiology Department (N.P., E.C., D.D., M.A.-S.) nadya.pyatigorskaya@gmail.com.
Background And Purpose:
PET/MRI with 18F-FDG has demonstrated the advantages of simultaneous PET and MR imaging in head and neck cancer imaging, MRI allowing excellent soft-tissue contrast, while PET provides metabolic information. The aim of this study was to evaluate the added value of gadolinium contrast-enhanced sequences in the tumor delineation of head and neck cancers on 18F-FDG-PET/MR imaging.
Materials And Methods:
Consecutive patients who underwent simultaneous head and neck 18F-FDG-PET/MR imaging staging or restaging followed by surgery were retrospectively included. Local tumor invasion and lymph node extension were assessed in 45 head and neck anatomic regions using 18F-FDG-PET/MR imaging by 2 rater groups (each one including a radiologist and a nuclear medicine physician). Two reading sessions were performed, one without contrast-enhanced sequences (using only T1WI, T2WI, and PET images) and a second with additional T1WI postcontrast sequences. The results were compared with the detailed histopathologic analysis, used as reference standard. The κ concordance coefficient between the reading sessions and sensitivity and specificity for each region were calculated.
Results:
Thirty patients were included. There was excellent agreement between the contrast-free and postgadolinium reading sessions in delineating precise tumor extension in the 45 anatomic regions studied (Cohen κ = 0.96, 95% CI = [0.94-0.97], P < .001). The diagnostic accuracy did not differ between contrast-free and postgadolinium reading sessions, being 0.97 for both groups and both reading sessions. For the 2 rater groups, there was good sensitivity for both contrast-free (0.83 and 0.85) and postgadolinium reading sessions (0.88 and 0.90, respectively). Moreover, there was excellent specificity (0.98) for both groups and reading sessions.
Conclusions:
Gadolinium chelate contrast administration showed no added value for accurate characterization of head and neck primary tumor extension and could possibly be avoided in the PET/MR imaging head and neck workflow.
Insights
Gadolinium contrast does not improve head and neck cancer delineation on 18F-FDG-PET/MR imaging. This finding suggests contrast agents may be safely omitted in this workflow, streamlining imaging procedures.
Area of Science:
- Oncology
- Radiology
- Nuclear Medicine
Background:
- Positron Emission Tomography/Magnetic Resonance Imaging (PET/MRI) combines metabolic and soft-tissue contrast information for head and neck cancer.
- 18F-FDG PET/MRI is a valuable tool for staging and restaging head and neck cancers.
Purpose of the Study:
- To assess the added value of gadolinium contrast-enhanced sequences for tumor delineation in head and neck cancers using 18F-FDG PET/MRI.
- To determine if contrast agents improve the accuracy of tumor staging and restaging in head and neck cancer patients.
Main Methods:
- Retrospective analysis of 30 patients undergoing simultaneous 18F-FDG PET/MRI for head and neck cancer.
- Two reading sessions were conducted: one without contrast-enhanced MRI sequences and one with T1WI postcontrast sequences.
- Tumor invasion and lymph node extension were assessed in 45 anatomic regions and compared to histopathology, with Cohen's kappa and diagnostic accuracy calculated.
Main Results:
- Excellent agreement (Cohen κ = 0.96) was observed between contrast-free and postgadolinium reading sessions for tumor delineation.
- Diagnostic accuracy was high and similar for both reading sessions (0.97).
- Sensitivity and specificity for detecting tumor invasion and lymph node extension were good to excellent in both contrast-free and postgadolinium settings.
Conclusions:
- Gadolinium contrast administration does not provide added value for the accurate characterization of primary head and neck tumor extension.
- Contrast-enhanced sequences can potentially be omitted from the 18F-FDG PET/MRI imaging workflow for head and neck cancers.
- This omission may streamline the imaging process without compromising diagnostic accuracy.
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