Local recurrence of squamous cell carcinoma of the head and neck after radio(chemo)therapy: Diagnostic performance of FDG-PET/MRI with diffusion-weighted sequences

Eur Radiol. 2018 Feb;28(2):651-663. doi: 10.1007/s00330-017-4999-1. Epub 2017 Aug 15.


Purpose: To determine the diagnostic performance of FDG-PET/MRI with diffusion-weighted imaging (FDG-PET/DWIMRI) for detection and local staging of head and neck squamous cell carcinoma (HNSCC) after radio(chemo)therapy.

Materials and methods: This was a prospective study that included 74 consecutive patients with previous radio(chemo)therapy for HNSCC and in whom tumour recurrence or radiation-induced complications were suspected clinically. The patients underwent hybrid PET/MRI examinations with morphological MRI, DWI and FDG-PET. Experienced readers blinded to clinical/histopathological data evaluated images according to established diagnostic criteria taking into account the complementarity of multiparametric information. The standard of reference was histopathology with whole-organ sections and follow-up ≥24 months. Statistical analysis considered data clustering.

Results: The proof of diagnosis was histology in 46/74 (62.2%) patients and follow-up (mean ± SD = 34 ± 8 months) in 28/74 (37.8%). Thirty-eight patients had 43 HNSCCs and 46 patients (10 with and 36 without tumours) had 62 benign lesions/complications. Sensitivity, specificity, and positive and negative predictive value of PET/DWIMRI were 97.4%, 91.7%, 92.5% and 97.1% per patient, and 93.0%, 93.5%, 90.9%, and 95.1% per lesion, respectively. Agreement between imaging-based and pathological T-stage was excellent (kappa = 0.84, p < 0.001).

Conclusion: FDG-PET/DWIMRI yields excellent results for detection and T-classification of HNSCC after radio(chemo)therapy.

Key points: • FDG-PET/DWIMRI yields excellent results for the detection of post-radio(chemo)therapy HNSCC recurrence. • Prospective one-centre study showed excellent agreement between imaging-based and pathological T-stage. • 97.5% of positive concordant MRI, DWI and FDG-PET results correspond to recurrence. • 87% of discordant MRI, DWI and FDG-PET results correspond to benign lesions. • Multiparametric FDG-PET/DWIMRI facilitates planning of salvage surgery in the irradiated neck.

Keywords: Head and neck neoplasms; Imaging, hybrid; Magnetic resonance imaging; Multimodal imaging; Neoplasm recurrence, local.

MeSH terms

  • Adult
  • Aged
  • Carcinoma, Squamous Cell / diagnosis*
  • Carcinoma, Squamous Cell / therapy
  • Chemoradiotherapy
  • Diffusion Magnetic Resonance Imaging / methods*
  • Female
  • Fluorodeoxyglucose F18 / pharmacology*
  • Head and Neck Neoplasms / diagnosis*
  • Head and Neck Neoplasms / therapy
  • Humans
  • Male
  • Middle Aged
  • Neoplasm Recurrence, Local / diagnosis*
  • Positron-Emission Tomography / methods*
  • Prospective Studies
  • Radiopharmaceuticals / pharmacology
  • Squamous Cell Carcinoma of Head and Neck


  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18