FDG-PET/CT pitfalls in oncological head and neck imaging

Area of Science:

• Nuclear medicine imaging
• Oncologic imaging
• Head and neck radiology

Background:

• Fluorine-18-fluorodeoxy-D-glucose (FDG) Positron Emission Tomography-Computed Tomography (PET/CT) is crucial for head and neck cancer diagnosis.
• Complex anatomy and physiological variations can complicate FDG PET/CT interpretation.
• Identifying unusual FDG uptake patterns is key to accurate assessment.

Purpose of the Study:

• To provide a comprehensive approach to interpreting FDG PET/CT in head and neck imaging.
• To highlight key imaging features and interpretation pitfalls.
• To guide clinicians in avoiding diagnostic errors.

Main Methods:

• Review of pathophysiological mechanisms causing false-positive and false-negative results.
• Discussion of complementary imaging techniques: high-resolution contrast-enhanced head and neck PET/CT (HR HN PET/CT), ultrasound (US), and magnetic resonance imaging (MRI).

Main Results:

• Common false-positive pitfalls include physiological uptake, benign thyroid nodules, cranial nerve palsy, and inflammation.
• False-negative findings arise from proximity to high-metabolism structures, dental hardware, scanner resolution limits, and low tumor avidity.
• Recent chemoradiotherapy and surgery can also cause increased FDG uptake.

Conclusions:

• Awareness of unusual FDG uptake patterns and modality limitations is essential for interpreting head and neck PET/CT.
• Accurate interpretation prevents overdiagnosis of benign conditions and missed malignancies.
• Correlation with contrast-enhanced CT, US, or MRI improves diagnostic precision.