Metabolic imaging of head and neck lesions: Differentiating dental and maxillofacial conditions using positron emission tomography/computed tomography

Aim: Fluorine-18-labeled fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) is an essential oncologic imaging modality, but its uptake patterns may also be seen in benign inflammatory or structural oral conditions, leading to diagnostic confusion. This study aims to compare metabolic activity with maximum standardized uptake value (SUVmax) among common dento-maxillofacial conditions---dental artifacts, periodontal infections, maxillary sinus pathologies, and temporomandibular joint (TMJ) disorders---against confirmed malignant lesions, to guide differential diagnosis and improve clinical interpretation. Materials and Methods: A total of 100 FDG-PET/CT scans were retrospectively analyzed. Inclusion criteria comprised pre-treatment scans with available CT or magnetic resonance imaging (MRI) acquired within four weeks. Patients were categorized into five groups: Dental Artifacts (n=19), Periodontal Infections (n=23), Maxillary Sinus Pathologies (n=21), TMJ Pathologies (n=19), and Malignant Dento-maxillofacial Lesions (n=18; control group). All scans were reviewed by an oral and maxillofacial radiologist and a radiologist. SUVmax were calculated using a 42% threshold. Statistical analyses were conducted using Kruskal-Wallis and MannWhitney U tests with Bonferroni correction. Results: Significant differences in SUVmax were observed across all groups (χ² = 77.4, p<0.000001). The malignant lesion group demonstrated the highest metabolic activity (mean SUVmax = 12.5 ± 3.0), significantly greater than all other groups (p<0.000001). Among nonmalignant conditions, maxillary sinus pathologies showed the highest SUVmax (4.2 ± 1.0), followed by periodontal infections (3.5 ± 0.8). TMJ pathologies and dental artifacts exhibited the lowest FDG uptake (2.0 ± 0.6 and 2.5 ± 0.7, respectively), suggesting minimal metabolic activity. Conclusion: This study confirms that malignant dento-maxillofacial lesions exhibit significantly higher FDG uptake compared to inflammatory and mechanical conditions. Understanding these uptake patterns is crucial to avoiding false-positive interpretations, especially in oncologic patients. Multimodal imaging and interdisciplinary evaluation are recommended for accurate differentiation of dental and maxillofacial pathologies in FDG-PET/CT interpretation.