Dual-energy subtraction imaging for diagnosing vocal cord paralysis with flat panel detector radiography.
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.
Machida
Haruhiko
H
Department of Radiology, Tokyo Women's Medical University Medical Center East, Arakawa-ku, Tokyo, Japan. machira@dnh.twmu.ac.jp
Yoda
Keiko
K
Arai
Yasuko
Y
Nishida
Suguru
S
Masukawa
Ai
A
Asanuma
Masayasu
M
Yuhara
Toshiyuki
T
Morita
Satoru
S
Suzuki
Kazufumi
K
Ueno
Eiko
E
Sabol
John M
JM
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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