Clinical evaluation of [18F]fluoro-2-deoxy-d-glucose positron emission tomography-magnetic resonance imaging ([18F]FDG PET-MRI) and [18F]FDG PET-computed tomography ([18F]FDG PET-CT) for lymph node assessment in head and neck squamous cell carcinoma.

AIM: This retrospective study evaluated the accuracy of hybrid 2-[18F]fluoro-2-deoxy-d-glucose ([18F]FDG) positron emission tomography-magnetic resonance imaging (PET-MRI) and [18F]fluoro-2-deoxy-d-glucose positron emission tomography-computed tomography ([18F]FDG PET-CT) for lymph node assessment in patients with head and neck squamous cell carcinoma (HNSCC) within routine clinical care.

MATERIALS AND

METHODS

Patients with HNSCC underwent either [18F]FDG PET-MRI or [18F]FDG PET-CT following a dedicated head and neck and whole-body protocol. Data on lymph nodes, both individually and pooled by ipsilateral and contralateral sides, were extracted from [18F]FDG PET-MRI/-CT reports. Lymph nodes and sides were categorised as malignant, suspicious, or benign. As a reference standard, results from pathology, follow-up imaging, or the conclusion established by a multidisciplinary team were used. Both lesion-wise and patient-wise analyses were performed.

RESULTS

A total of 256 patients were included: 130 underwent [18F]FDG PET-MRI (mean age 65 ± 11, 69% male) and 126 underwent [18F]FDG PET-CT (mean age 68 ± 10, 69% male). For lymph nodes classified as malignant or benign, both modalities showed high true-positive and negative rates (96-100%) in both lesion- and patient-wise analyses. Lymph nodes deemed suspicious on [18F]FDG PET-MRI and [18F]FDG PET-CT were pathologically confirmed as malignant in 18% and 9% of cases, respectively.

CONCLUSION

[18F]FDG PET-MRI/-CT demonstrate high accuracy in identifying malignant and benign lymph nodes. [18F]FDG PET-MRI shows slightly higher accuracy for suspicious lymph nodes, although diagnostic challenges remain. Advancements in imaging techniques and disease-specific tracers may improve lymph node evaluation in HNSCC, warranting prospective clinical trials to ultimately reduce reliance on pathological confirmation and minimise diagnostic delays.