title: MR of denervated tongue: temporal changes after radical neck dissection.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the temporal changes of MR imaging in the denervated tongue after a radical neck dissection.
  
  
  METHODS
  One hundred seventy-four consecutive MR studies in 116 patients with radical neck dissections for malignant tumors of the head and neck were evaluated retrospectively. Patients with tumors involving the tongue or hypoglossal nerve were not included in this study.
  
  
  RESULTS
  Abnormal signal intensity and/or hemiatrophy on the side of the tongue operated on was seen in 22 patients who had hypoglossal paralysis after radical neck dissection. The denervated side of the tongue appeared hypointense to hyperintense relative to the normal side on T1-weighted images and hyperintense on T2-weighted images. Signal intensity ratios of the abnormal to normal muscles were 0.9-1.6 on T1-weighted images and 1.3-2.8 on T2-weighted images. High signal intensity on T1-weighted images appeared 5 months or more after the dissection, whereas on T2-weighted images, the most prominent increases in signal intensity appeared in the first several months after denervation. Hemiatrophy of the tongue was observed on MR images obtained more than 6 months after surgery.
  
  
  CONCLUSIONS
  MR findings in the denervated tongue are compatible with histologic changes and are characterized by an enlarged extracellular fluid space or fatty infiltration. The pattern of signal intensity and the degree of hemiatrophy suggest the duration of denervation.
authors.affiliation: Department Radiology, Kumamoto University School of Medicine, Honjo, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Murakami
authors.forename: Y
authors.initials: Y
authors.lastname: Baba
authors.forename: R
authors.initials: R
authors.lastname: Nishimura
authors.forename: T
authors.initials: T
authors.lastname: Baba
authors.forename: T
authors.initials: T
authors.lastname: Okuda
authors.forename: D
authors.initials: D
authors.lastname: Utsunomiya
authors.forename: T
authors.initials: T
authors.lastname: Ishikawa
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
mesh_terms: D000328:Adult; D001284:Atrophy / Q000473:pathology; D003389:Cranial Nerve Diseases / Q000175:diagnosis / Q000209:etiology; D003714:Denervation; D005260:Female; D006258:Head and Neck Neoplasms / Q000601:surgery*; D006801:Humans; D007002:Hypoglossal Nerve / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D009333:Neck / Q000601:surgery*; D010243:Paralysis / Q000175:diagnosis / Q000209:etiology; D011183:Postoperative Complications; D011184:Postoperative Period; D012189:Retrospective Studies; D013997:Time Factors; D014059:Tongue / Q000294:innervation* / Q000473:pathology*