Abnormal vocal cord function in difficult-to-treat asthma

Rationale: Upper airway dysfunction may complicate asthma but has been largely ignored as an etiological factor. Diagnosis using endoscopic evaluation of vocal cord function is difficult to quantify, with limited clinical application.Objectives: A novel imaging technique, dynamic 320-slice computerized tomography (CT), was used to examine laryngeal behavior in healthy individuals and individuals with asthma.Methods: Vocal cord movement was imaged using 320-slice CT larynx. Healthy volunteers were studied to develop and validate an analysis algorithm for quantification of normal vocal cord function. Further studies were then conducted in 46 patients with difficult-to-treat asthma.Measurements and Main Results: Vocal cord movement was quantified over the breathing cycle by CT using the ratio of vocal cord diameter to tracheal diameter. Normal limits were calculated, validated, and applied to evaluate difficult-to-treat asthma. Vocal cord movement was abnormal with excessive narrowing in 23 of 46 (50%) patie...