title: Parotid gland tumours: MR tractography to assess contact with the facial nerve.
abstract: OBJECTIVE
  To assess the feasibility of intraparotid facial nerve (VIIn) tractographic reconstructions in estimating the presence of a contact between the VIIn and the tumour, in patients requiring surgical resection of parotid tumours.
  
  
  METHODS
  Patients underwent MR scans with VIIn tractography calculated with the constrained spherical deconvolution model. The parameters of the diffusion sequence were: b-value of 1000 s/mm(2); 32 directions; voxel size: 2 mm isotropic; scan time: 9'31'. The potential contacts between VIIn branches and tumours were estimated with different initial fractional anisotropy (iFA) cut-offs compared to surgical data. Surgeons were blinded to the tractography reconstructions and identified both nerves and contact with tumours using nerve stimulation and reference photographs.
  
  
  RESULTS
  Twenty-six patients were included in this study and the mean patient age was 55.2 years. Surgical direct assessment of VIIn allowed identifying 0.1 as the iFA threshold with the best sensitivity to detect tumour contact. In all patients with successful VIIn identification by tractography, surgeons confirmed nerve courses as well as lesion location in parotid glands. Mean VIIn branch FA values were significantly lower in cases with tumour contact (t-test; p ≤ 0.01).
  
  
  CONCLUSIONS
  This study showed the feasibility of intraparotid VIIn tractography to identify nerve contact with parotid tumours.
  
  
  CONCLUSIONS
  • Diffusion imaging is an efficient method for highlighting the intraparotid VIIn. • Visualization of the VIIn may help to better manage patients before surgery. • We bring new insights to future trials for patients with VIIn dysfunction. • We aimed to provide radio-anatomical references for further studies.
authors.affiliation: Department of Neuroradiology and MRI, Grenoble University Hospital - SFR RMN Neurosciences, Grenoble, France. aattye@chu-grenoble.fr.|Inserm, US 17, Grenoble, France. aattye@chu-grenoble.fr.|University Grenoble Alpes, IRMaGe, F-38000, Grenoble, France. aattye@chu-grenoble.fr.|Neuroradiology and MR Unit, CS 10217- Grenoble University Hospital, F-38043, Grenoble, Cedex 9, France. aattye@chu-grenoble.fr.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Attyé
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University Hospital of Grenoble, Grenoble, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Karkas
authors.affiliation: Inserm, US 17, Grenoble, France.|University Grenoble Alpes, IRMaGe, F-38000, Grenoble, France.|CNRS, UMS 3552, Grenoble, France.
authors.forename: Irène
authors.initials: I
authors.lastname: Troprès
authors.affiliation: Department of Statistics, University Hospital of Grenoble, Grenoble, France.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Roustit
authors.affiliation: Department of Neuroradiology and MRI, Grenoble University Hospital - SFR RMN Neurosciences, Grenoble, France.|Inserm, US 17, Grenoble, France.|University Grenoble Alpes, IRMaGe, F-38000, Grenoble, France.
authors.forename: Adrian
authors.initials: A
authors.lastname: Kastler
authors.affiliation: Department of Maxillofacial Surgery, University Hospital of Grenoble, Grenoble, France.
authors.forename: Georges
authors.initials: G
authors.lastname: Bettega
authors.affiliation: Inserm, US 17, Grenoble, France.|University Grenoble Alpes, IRMaGe, F-38000, Grenoble, France.|CNRS, UMS 3552, Grenoble, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Lamalle
authors.affiliation: University Grenoble Alpes, IRMaGe, F-38000, Grenoble, France.
authors.forename: Félix
authors.initials: F
authors.lastname: Renard
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, University Hospital of Grenoble, Grenoble, France.|Albert Bonniot Institute, Grenoble, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Righini
authors.affiliation: Department of Neuroradiology and MRI, Grenoble University Hospital - SFR RMN Neurosciences, Grenoble, France.|Inserm, US 17, Grenoble, France.|University Grenoble Alpes, IRMaGe, F-38000, Grenoble, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Krainik
mesh_terms: D000235:Adenolymphoma / Q000000981:diagnostic imaging* / Q000601:surgery; D018249:Adenoma, Oxyphilic / Q000000981:diagnostic imaging* / Q000601:surgery; D008949:Adenoma, Pleomorphic / Q000000981:diagnostic imaging* / Q000601:surgery; D003528:Carcinoma, Adenoid Cystic / Q000000981:diagnostic imaging* / Q000601:surgery; D003560:Cysts / Q000000981:diagnostic imaging* / Q000601:surgery; D056324:Diffusion Tensor Imaging; D005154:Facial Nerve / Q000000981:diagnostic imaging*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010305:Parotid Diseases / Q000000981:diagnostic imaging / Q000601:surgery; D010307:Parotid Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D011446:Prospective Studies
keywords: Diffusion tractography; Facial nerve; Magnetic resonance imaging; Parotid gland; Salivary gland neoplasms