title: Is There a Magnetic Resonance Imaging-Discernible Cause for Trigeminal Neuralgia? A Structured Review.
abstract: BACKGROUND
  Trigeminal neuralgia (TN) is a chronic brain condition involving the trigeminal nerve and characterized by severe and recurrent facial pain. Although the cause of TN has been researched extensively, there is a lack of convergence on the physiologic processes leading to pain symptoms. This review seeks to better elucidate the underlying pathophysiology of TN by analyzing the outcomes of studies that use magnetic resonance structural imaging and diffusion-weighted imaging to examine nerve damage in patients with TN.
  
  
  METHODS
  Performing a structured review of the literature, the authors included human magnetic resonance anatomic and diffusion-weighted imaging studies aimed at visualizing the trigeminal nerve or measuring neural damage pertaining to TN. Studies that measured and compared nerve damage in the affected and unaffected sides in patients or patients and controls were analyzed for neural changes associated with TN.
  
  
  RESULTS
  Twenty-five studies met inclusion criteria. Overall, the data from the anatomic and diffusion studies showed decreased volume and cross-sectional area, decreased fractional anisotropy, and increased apparent diffusion coefficient and diffusivity associated with the affected side of patients compared with the unaffected side as well as in patients compared with controls.
  
  
  CONCLUSIONS
  A review of the studies included indicates that neural differences exist between the affected and unaffected sides in patients as well as between patients and controls in both structural and diffusion metrics. The amalgamated data suggest that damage of the trigeminal nerve tissue is commonly found in patients with TN and could be a primary factor in TN pathophysiology.
authors.affiliation: Icahn School of Medicine at Mount Sinai, The Translational and Molecular Imaging Institute, New York, New York, USA; Grove School of Engineering, Department of Biomedical Engineering, City College of New York, New York, New York, USA. Electronic address: judy.alper@mssm.edu.
authors.forename: Judy
authors.initials: J
authors.lastname: Alper
authors.affiliation: Department of Neurosurgery, Mount Sinai Medical Center, New York, New York, USA.
authors.forename: Raj K
authors.initials: RK
authors.lastname: Shrivastava
authors.affiliation: Icahn School of Medicine at Mount Sinai, The Translational and Molecular Imaging Institute, New York, New York, USA.
authors.forename: Priti
authors.initials: P
authors.lastname: Balchandani
mesh_terms: D016880:Anisotropy; D016206:Databases, Bibliographic / Q000706:statistics & numerical data; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D014277:Trigeminal Neuralgia / Q000000981:diagnostic imaging* / Q000503:physiopathology*
keywords: Diffusion-weighted imaging; Magnetic resonance imaging; Nerve damage; Trigeminal neuralgia