title: Three-dimensional versus two-dimensional sonography of the temporomandibular joint in comparison to MRI.
abstract: OBJECTIVE
  To compare clinical feasibility of static two-dimensional (2D) to three-dimensional (3D) sonography of the temporomandibular joint (TMJ) in assessment of disk dislocation and joint degeneration compared to magnetic resonance imaging (MRI).
  
  
  METHODS
  Thirty-three patients, 66 TMJ were prospectively sonographed 2D and 3D (8-12.5MHz step motor scan), in occlusion and maximum opening with a probe position parallel inferior to the zygomatic arch. Axial 2D images were judged independent from the 3D scans; 3D volumes were cut axial, sagittal, frontal and rotated in real-time. Disk position and joint degeneration were assessed and compared to a subsequent MRI examination.
  
  
  RESULTS
  The specific appearance of the disk was hypoechogenic overlying a hyperechogenic condyle in axial (2D) or sagittal and frontal (3D) viewing. Specificity of 2D sonography for disk dislocation was 63%, sensitivity 58%, accuracy 64%, positive predictive value 46%, negative predictive value 73%; for joint degeneration synonymously 59/68/61/38/83%. 3D sonography for disk displacement reached synonymously 68/60/69/51/76%, for joint degeneration 75/65/73/48/86%. 2D sonographic diagnoses of disk dislocation in the closed mouth position and of joint degeneration showed significantly different results from the expected values (MRI) in chi(2) testing; 3D diagnoses of disk dislocation in closed mouth position, of joint degeneration, 2D and 3D diagnoses in open mouth position were nonsignificant.
  
  
  CONCLUSIONS
  Acceptable was the overall negative predictive value, as specificity and accuracy for joint degeneration in 3D. 3D appears superior diagnosing disk dislocation in closed mouth position as for overall joint degeneration. Sensitivity, accuracy and positive predictive value will have to ameliorate with future equipment of higher resolution in real-time 2D and 3D, if sonographic screening shall be clinically applied prior to MRI.
authors.affiliation: Oral, Maxillofacial & Plastic Facial Surgery, The Frankfurt University Medical Centre, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany. c.landes@lycos.com
authors.forename: Constantin A
authors.initials: CA
authors.lastname: Landes
authors.forename: Wojciech A
authors.initials: WA
authors.lastname: Goral
authors.forename: Robert
authors.initials: R
authors.lastname: Sader
authors.forename: Martin G
authors.initials: MG
authors.lastname: Mack
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008335:Mandibular Condyle / Q000000981:diagnostic imaging; D008875:Middle Aged; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D019224:Temporomandibular Joint Disc / Q000000981:diagnostic imaging / Q000473:pathology; D013705:Temporomandibular Joint Disorders / Q000000981:diagnostic imaging*; D014463:Ultrasonography / Q000379:methods