Dynamic 320-slice computerised tomography of the larynx to evaluate vocal CORD dysfunction in asthma.

Rationale: Vocal cord dysfunction (VCD) may mimic asthma or make asthma more difficult to control. We have recently demonstrated the utility of 320-slice CT larynx to detect this condition (Holmes et al, Respirology 2009). Dynamic 320-slice CT can demonstrate real-time laryngeal function during the respiratory cycle. Method(s): Dynamic laryngeal function was imaged in a follow-up cohort of patients (n=16) with breathlessness and suspected VCD. Patient demographics (age 48.6 years, females 11/16, BMI 34.6kg/m2 and prior oral corticosteroid use 10/16) suspected diagnosis, symptoms, lung function measurements, 320-slice CT results and response to treatment were obtained. Asthma was classified (GINA) as severe in 8/11, moderate in 2/11, and mild in 1/11 subjects. We defined VCD as luminal area in the larynx reduced to <60% during expiration or <50% of tracheal diameter if inspiration and expiration both abnormal. Result(s): Sixteen patients with breathlessness were assessed by 320-slice CT larynx, providing explicit images of laryngeal function. VCD was detected in 8/11 patients suspected of having asthma with VCD and abnormal laryngeal function was present mostly during expiration (10/11). VCD was found in 6/8 patients with severe asthma and in 1/2 with moderate disease. CT also detected evidence of 'primary' VCD without asthma (2/2) and demonstrated other laryngeal abnormalities in 3/3 cases. Initial results indicate that speech therapy was of benefit in most patients with VCD present. Clinically patients with VCD had no distinguishing clinical characteristics although they tended to be female and obese (9/11). Conclusion(s): Dynamic 320-slice CT provided evidence of VCD and other laryngeal pathology in patients with respiratory symptoms. Diagnostic pathways using dynamic CT to evaluate VCD and its role in severe asthma require further investigation.