title: Otosclerosis: anatomy and pathology in the temporal bone assessed by multi-slice and cone-beam CT.
abstract: OBJECTIVE
  To assess the use of cone beam computed tomography (CBCT) compared with multi-slice computed tomography (MSCT) in otosclerosis, with special emphasis on middle- and inner-ear anatomy.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Twenty patients who underwent a stapedectomy 30 years ago were selected on the basis of bone conduction threshold values. Their mean age was 65 years (range, 48-76 yr).
  
  
  METHODS
  All patients underwent CBCT and MSCT with a slice thickness of 0.5 to 0.6 mm.
  
  
  METHODS
  Sixteen middle- and inner-ear anatomic structures and stapedial prostheses were analyzed by visual grading analysis. To assess critical reproduction and thereby the clinical applicability of CBCT, a dichotomization was made. Assessment of otosclerotic foci was performed using a grading system dividing the lesions in; (1) sole fenestral lesions, (2) retrofenestral lesions with or without fenestral lesions and (3) severe retrofenestral lesions.
  
  
  RESULTS
  The 16 anatomic structures were clearly reproduced by both imaging techniques. However, there was an interobserver variation in judging the superiority of 1 method in favor of the other. Otosclerotic lesions were diagnosed in 80/95% using MSCT and 50/85% using CBCT (evaluators 1 and 2, respectively). Retrofenestral lesions were diagnosed in 5 of 10 of ears with severe-to-profound hearing loss, whereas no retrofenestral lesions were diagnosed in the 10 ears with mild-to-moderate hearing loss. The stapedial prostheses were adequately or very well reproduced by both methods.
  
  
  CONCLUSIONS
  CBCT is a new imaging technique with a considerably lower radiation dose than conventional MSCT. Our study indicates that CBCT is suitable and, in many ways, equivalent to MSCT, for temporal bone imaging in otosclerosis.
authors: Department of Otolaryngology, Institute of Clinical Sciences, Jönköping, Sweden. ylva.dahlin-redfors@vgregion.se
authors: Ylva Dahlin
authors: YD
authors: Redfors
authors: Hans Göran
authors: HG
authors: Gröndahl
authors: Johan
authors: J
authors: Hellgren
authors: Ninita
authors: N
authors: Lindfors
authors: Inger
authors: I
authors: Nilsson
authors: Claes
authors: C
authors: Möller
mesh_terms: D000368:Aged; D001844:Bone Conduction; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D007758:Ear, Inner / Q000000981:diagnostic imaging; D004432:Ear, Middle / Q000000981:diagnostic imaging; D005260:Female; D005276:Fenestration, Labyrinth / Q000379:methods; D034381:Hearing Loss / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010040:Otosclerosis / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D013201:Stapes Surgery; D013701:Temporal Bone / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*