title: MR neurographic orthopantomogram: Ultrashort echo-time imaging of mandibular bone and teeth complemented with high-resolution morphological and functional MR neurography.
abstract: Panoramical radiographs or cone-beam computed tomography (CT) are the standard-of-care in dental imaging to assess teeth, mandible, and mandibular canal pathologies, but do not allow assessment of the inferior alveolar nerve itself nor of its branches. We propose a new technique for "MR neurographic orthopantomograms" exploiting ultrashort echo-time (UTE) imaging of bone and teeth complemented with high-resolution morphological and functional MR neurography.
  
  
  
  The Institutional Review Board approved the study in 10 healthy volunteers. Imaging of the subjects mandibles at 3.0T (Magnetom Skyra, Siemens-Healthcare) using a 64-channel head coil with isotropic spatial resolution for subsequent multiplanar reformatting, was performed. Bone images were acquired using a 3D PETRA sequence (TE, 0.07 msec). Morphological nerve imaging was performed using a dedicated 3D PSIF and 3D SPACE STIR sequence. Functional MR neurography was accomplished using a new accelerated diffusion-tensor-imaging (DTI) prototype sequence (2D SMS-accelerated RESOLVE). Qualitative and quantitative image analysis was performed and descriptive statistics are provided.
  
  
  
  Image acquisition and subsequent postprocessing into the MR neurographic orthopantomogram by overlay of morphological and functional images were feasible in all 10 volunteers without artifacts. All mandibular bones and mandibular nerves were assessable and considered normal. Fiber tractography with quantitative evaluation of physiological diffusion properties of mandibular nerves yielded the following mean ± SD values: fractional anisotropy, 0.43 ± 0.07; mean diffusivity (mm(2) /s), 0.0014 ± 0.0002; axial diffusivity, 0.0020 ± 0.0002, and radial diffusivity, 0.0011 ± 0.0001.
  
  
  
  The proposed technique of MR neurographic orthopantomogram exploiting UTE imaging complemented with high-resolution morphological and functional MR neurography was feasible and allowed comprehensive assessment of osseous texture and neural microarchitecture in a single examination. J. Magn. Reson. Imaging 2016;44:393-400.
authors: Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
authors: Andrei
authors: A
authors: Manoliu
authors: Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
authors: Michael
authors: M
authors: Ho
authors: Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
authors: Daniel
authors: D
authors: Nanz
authors: Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
authors: Evelyn
authors: E
authors: Dappa
authors: Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
authors: Andreas
authors: A
authors: Boss
authors: Siemens Healthcare, Erlangen, Germany.
authors: David M
authors: DM
authors: Grodzki
authors: Siemens Shenzhen Magnetic Resonance Ltd, Shenzhen, China.
authors: Wei
authors: W
authors: Liu
authors: Department of Radiology, Southwestern Medical Center, Dallas, Texas, USA.
authors: Avneesh
authors: A
authors: Chhabra
authors: Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
authors: Gustav
authors: G
authors: Andreisek
authors: Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
authors: Felix P
authors: FP
authors: Kuhn
mesh_terms: D000328:Adult; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging* / Q000294:innervation*; D059906:Neuroimaging / Q000379:methods*; D011862:Radiography, Panoramic / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D014070:Tooth / Q000000981:diagnostic imaging* / Q000294:innervation*
keywords: DTI peripheral nerves; MR neurography; PETRA; UTE; bone imaging; maxillofacial imaging