title: Dual-energy subtraction imaging for diagnosing vocal cord paralysis with flat panel detector radiography.
abstract: OBJECTIVE
  To investigate the clinical feasibility of dual energy subtraction (DES) imaging to improve the delineation of the vocal cord and diagnostic accuracy of vocal cord paralysis as compared with the anterior-posterior view of flat panel detector (FPD) neck radiography.
  
  
  METHODS
  For 122 consecutive patients who underwent both a flexible laryngoscopy and conventional/DES FPD radiography, three blinded readers retrospectively graded the radiographs during phonation and inspiration on a scale of 1 (poor) to 5 (excellent) for the delineation of the vocal cord, and in consensus, reviewed the diagnostic accuracy of vocal cord paralysis employing the laryngoscopy as the reference. We compared vocal cord delineation scores and accuracy of vocal cord paralysis diagnosis by both conventional and DES techniques using kappa statistics and assessing the area under the receiver operating characteristic curve (AUC).
  
  
  RESULTS
  Vocal cord delineation scores by DES (mean, 4.2 +/- 0.4) were significantly higher than those by conventional imaging (mean, 3.3 +/- 0.5) (p < 0.0001). Sensitivity for diagnosing vocal cord paralysis by the conventional technique was 25%, whereas the specificity was 94%. Sensitivity by DES was 75%, whereas the specificity was 96%. The diagnostic accuracy by DES was significantly superior (kappa = 0.60, AUC = 0.909) to that by conventional technique (kappa = 0.18, AUC = 0.852) (p = 0.038).
  
  
  CONCLUSIONS
  Dual energy subtraction is a superior method compared to the conventional FPD radiography for delineating the vocal cord and accurately diagnosing vocal cord paralysis.
authors.affiliation: Department of Radiology, Tokyo Women's Medical University Medical Center East, Arakawa-ku, Tokyo, Japan. machira@dnh.twmu.ac.jp
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Machida
authors.forename: Keiko
authors.initials: K
authors.lastname: Yoda
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Arai
authors.forename: Suguru
authors.initials: S
authors.lastname: Nishida
authors.forename: Ai
authors.initials: A
authors.lastname: Masukawa
authors.forename: Masayasu
authors.initials: M
authors.lastname: Asanuma
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Yuhara
authors.forename: Satoru
authors.initials: S
authors.lastname: Morita
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Suzuki
authors.forename: Eiko
authors.initials: E
authors.lastname: Ueno
authors.forename: John M
authors.initials: JM
authors.lastname: Sabol
mesh_terms: D015502:Absorptiometry, Photon / Q000295:instrumentation* / Q000379:methods*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D014826:Vocal Cord Paralysis / Q000000981:diagnostic imaging*; D014827:Vocal Cords / Q000000981:diagnostic imaging; D014963:X-Ray Intensifying Screens; D055815:Young Adult
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