Dental-Dedicated MRI in the Assessment of Pulp Vitality and Apical Periodontitis: A Feasibility Study

This feasibility study presents the diagnostic accuracy of a novel dental-dedicated magnetic resonance imaging (ddMRI) system for assessing pulp vitality and diagnosing apical periodontitis (AP), as an adjunct to clinical assessment and cone beam CT (CBCT) imaging.

Ten consecutive patients with possible endodontic problems were screened, and ultimately 18 teeth in nine patients (10 healthy teeth, five necrotic teeth with suspected AP and three necrotic or root canal treated teeth with no suspicion of AP) with a recent CBCT were included. The teeth were tested for vitality and clinical signs of AP. The CBCT volumes were assessed by three trained observers for signs of AP. The teeth were scanned using the Magnetom Free.Max Dental Edition ddMRI system (Siemens Healthineers, Forchheim, Germany), operating at 0.55 T with a seven-channel dental-dedicated surface coil. Six pulse sequences optimised for periapical diagnostics were applied, with a total scanning time of approximately 18 min per tooth. Images were assessed by three trained observers for anatomical structure conspicuity (root tip, periapical bone and lamina dura), pulp vitality determined by presence of signal and presence of AP determined by accumulation of fluid in the periapical area. The assessed pulp vitality status and presence of AP on ddMRI were compared to the clinical and radiological findings. Inter-modality agreement was calculated using kappa statistics, and diagnostic accuracy was evaluated with consensus between clinical findings and CBCT imaging as the reference standard.

All anatomical structures were visible in all cases. ddMRI showed high diagnostic accuracy. For pulp vitality, the inter-modality agreement kappa was 0.77 and accuracy was 0.88. For AP, the inter-modality agreement kappa was 0.87 and accuracy was 0.94.

ddMRI show promising results as a non-ionising imaging modality for assessment of pulp vitality and diagnosis of AP. This feasibility study demonstrates the potential of ddMRI to provide accurate diagnostic support, laying a foundation for larger-scale validation studies and clinical applications.