MedWire News: High-definition, high-speed dynamic volume computed tomography (CT) is effective for identifying vocal cord dysfunction (VCD) in patients with asthma, researchers have found.
“VCD often masquerades as asthma and reports have suggested that up to 30% of patients with asthma may have coexistent VCD,” explain Philip Bardin (Monash University, Melbourne, Victoria, Australia) and team in the journal Respirology.
However, they add: “Diagnosis of VCD is difficult, in part because it involves laryngoscopy which has practical constraints, and there is need for rapid non-invasive diagnosis.”
To investigate whether high-speed 320-slice volume CT is effective for identifying VCD, the researchers compared laryngeal anatomy and movement in a patient with subglottic stenosis and in a patient with confirmed VCD using both endoscopy and dynamic volume CT.
Reductions of at least 40% in vocal cord luminal area lasting for at least 70% of inspiration/expiration were considered to be indicative of VCD.
They then assessed nine patients with asthma, aged between 30 and 75 years, with suspected VCD using 320-slice dynamic volume CT alone. There were no significant clinical differences between the patients.
Using the CT technique, the team found that four of the patients had evidence of VCD, with a median reduction of 78.2% in luminal area during expiration compared with a mean reduction of just 10.4% in the remaining five patients.
All four patients with VCD then received speech therapy for the condition, which resulted in significant symptomatic improvements in three patients after 4 weeks. These three patients also showed significant reductions in their use of beta-agonists after 4 weeks.
Bardin and team conclude: “High definition, high speed dynamic volume CT… has the capacity to provide a simple, non-invasive investigation to identify laryngeal dysfunction.”
They add: “Verification of suspected VCD in severe asthmatics has far-reaching implications for clinical management. It will redirect the emphasis of management in these patients to alternative strategies, such as retraining of vocal cord function and other approaches for VCD. This will have the associated potential benefit of limiting corticosteroid use.”
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