title: Imaging findings of neurogenic tumours in the head and neck region.
abstract: OBJECTIVE
  The aim of this study was to describe the CT, MRI and ultrasonography findings of five cases of neurogenic tumours in the head and neck region.
  
  
  METHODS
  Five neurogenic tumours were analysed with respect to their CT value, the presence of cystic change, target sign, lobulation, connection to the nerve and vascularity.
  
  
  RESULTS
  The contrast-enhanced CT (ECT) of the schwannomas demonstrated either a mass with low enhancement (two out of three cases), which reflected the predominant Antoni B components, or a mass with cystic changes, which was an Antoni A-based schwannoma displaying cystic changes (one out of three cases). On MRI, all tumours showed homogeneous and isointense signals for muscle on T₁ weighted images (T₁ WIs). T₂ weighted images (T₂ WIs) and gadolinium (Gd)-enhanced T₁ WIs demonstrated target sign in both schwannomas. Ultrasound examination showed a well-defined, ovoid or round hypoechoic mass. The direct connection to the nerve was demonstrated in two of the five cases. Lobulation was observed in only one of the five cases and cystic changes were observed in one of the five cases. In all of the cases, no vascularity was seen in power Doppler images (PDIs) obtained percutaneously.
  
  
  CONCLUSIONS
  Low-enhanced areas on ECTs can be specific for schwannomas, which suggests the predominance of Antoni B components. The target sign on T₂ WIs and Gd-enhanced T₁ WIs can be specific, which can be used to differentiate the two different components (Antoni A and Antoni B). The direct connection to the nerve can be a specific finding for neurogenic tumours; however, at present the sensitivity is 40%.
authors.affiliation: Department of Oral and Maxillofacial Radiology, Faculty of Dental Science, Kyushu University, Higashi-ku, Fukuoka, Japan. kami@rad.dent.kyushu-u.ac.jp
authors.forename: Y N
authors.initials: YN
authors.lastname: Kami
authors.forename: T
authors.initials: T
authors.lastname: Chikui
authors.forename: K
authors.initials: K
authors.lastname: Okamura
authors.forename: Y
authors.initials: Y
authors.lastname: Kubota
authors.forename: K
authors.initials: K
authors.lastname: Oobu
authors.forename: H
authors.initials: H
authors.lastname: Yabuuchi
authors.forename: E
authors.initials: E
authors.lastname: Nakayama
authors.forename: K
authors.initials: K
authors.lastname: Hashimoto
authors.forename: K
authors.initials: K
authors.lastname: Yoshiura
mesh_terms: D000328:Adult; D000368:Aged; D002339:Carotid Arteries / Q000473:pathology; D003287:Contrast Media; D003952:Diagnostic Imaging; D005260:Female; D005682:Gadolinium; D006258:Head and Neck Neoplasms / Q000175:diagnosis*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009060:Mouth Floor / Q000473:pathology; D009062:Mouth Neoplasms / Q000175:diagnosis; D009442:Neurilemmoma / Q000175:diagnosis*; D009455:Neurofibroma / Q000175:diagnosis*; D011856:Radiographic Image Enhancement / Q000379:methods; D013705:Temporomandibular Joint Disorders / Q000175:diagnosis; D014057:Tomography, X-Ray Computed / Q000379:methods; D018608:Ultrasonography, Doppler / Q000379:methods
chemical_list: D003287:Contrast Media; D005682:Gadolinium
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