Upper airway imaging in sleep apnoea syndrome: clinical applications

Symptoms of habitual snoring and excessive daytime sleepiness are extremely common in the general population, and have poor predictive value in identifying patients with "true" sleep-related disordered breathing. The upper airways are the main anatomical site responsible for snoring and sleep apnoea; therefore, their examination via different means has been quite extensively assessed. Clinical examination may point to severe micrognathia or retrognathia, grossly hypertrophied tonsils, obvious macroglossia, and oedema and inflammation of the uvula and soft palate. A recently proposed model is promising, but has not been validated independently yet. Endoscopic investigations have been performed in awake as well as in sleeping patients, with the pharynx in relaxed or active states; their predictive value remains poor, both for diagnostic purposes and for identifying patients that may benefit from surgery. Radiographic and magnetic resonance imaging techniques have permitted a detailed understanding of the process of narrowing and collapse of the upper airways. Unfortunately, these techniques do not perform any better than the ones previously cited as clinically efficient tools for diagnosis in the population of patients suspected of sleep-related breathing disorders. In conclusion, clinical examination of the upper airways remains part of the clinical evaluation of patients suspected of sleep-related disordered breathing. Other imaging techniques may be used for research purposes, but do not yet seem to be worth including in the routine assessment of this population.