title: Assessment of apical periodontitis by MRI: a feasibility study.
abstract: OBJECTIVE
  The purpose of this clinical feasibility study was to evaluate the applicability of magnetic resonance imaging (MRI) for the assessment of apical periodontitis in direct comparison with cone beam CT (CBCT).
  
  
  METHODS
  19 consecutive patients (average age 43 ± 13 years) with 34 lesions in total (13 molars, 14 premolars and 7 front teeth) were enrolled in this feasibility study. Periapical lesions were defined as periapical radiolucencies (CBCT) or structural changes in the spongy bone signal (MRI), which were connected with the apical part of a root and with at least twice the width of the periodontal ligament space. The location and dimension of the lesions were compared between MRI and CBCT.
  
  
  RESULTS
  While mainly mineralized tissue components such as teeth and bone were visible with CBCT, complimentary information of the soft tissue components was assessable with MRI. The MRI images provided sufficient diagnostic detail for the assessment of the main structures of interest. Heterogeneous contrast was observed within the lesion, with often a clear enhancement close to the apical foramen and the periodontal gap.  No difference for lesion visibility was observed between MRI and CBCT. The lesion dimensions corresponded well, but were slightly but significantly overestimated with MRI. A heterogeneous lesion appearance was observed in several patients. Four patients presented with a well circumscribed hyperintense signal in the vicinity of the apical foramen.
  
  
  CONCLUSIONS
  The MRI capability of soft tissue characterization may facilitate detailed analysis of periapical lesions. This clinical study confirms the applicability of multi-contrast MRI for the identification of periapical lesions.
  
  
  CONCLUSIONS
  MRI can be applied for the identification of periapical lesions without ionizing radiation exposure. MRI might facilitate more detailed characterization of periapical lesions. MRI might provide more accurate lesion dimensions as X-ray-based methods.
authors.affiliation: Oral and Maxillofacial Surgery, Ulm University, Ulm.
authors.forename: M A
authors.initials: MA
authors.lastname: Geibel
authors.affiliation: Internal Medicine II, Ulm University, Ulm, Germany.
authors.forename: E S
authors.initials: ES
authors.lastname: Schreiber
authors.affiliation: Internal Medicine II, Ulm University, Ulm, Germany.
authors.forename: A K
authors.initials: AK
authors.lastname: Bracher
authors.affiliation: Dental Imaging, Sirona Dental Systems GmbH, Bensheim, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Hell
authors.affiliation: Dental Imaging, Sirona Dental Systems GmbH, Bensheim, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Ulrici
authors.affiliation: MKG, DOC Praxisklinik im Wiley, Neu-Ulm, Germany.
authors.forename: L K
authors.initials: LK
authors.lastname: Sailer
authors.affiliation: Diagnostic and Interventional Radiology, Ulm University, Ulm, Germany.
authors.forename: Y
authors.initials: Y
authors.lastname: Ozpeynirci
authors.affiliation: Internal Medicine II, Ulm University, Ulm, Germany.
authors.forename: V
authors.initials: V
authors.lastname: Rasche
mesh_terms: D000328:Adult; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010485:Periapical Periodontitis / Q000175:diagnosis*; D012680:Sensitivity and Specificity; D019227:Tooth Apex / Q000473:pathology