Pharyngorofacial Imaging for Evaluation of Upper Airway and Sleep-Related Breathing Disorders

Upper airway imaging is a powerful technique to study the mechanisms underlying the pathogenesis, biomechanics, and efficacy of treatment options in patients with obstructive sleep apnea. Imaging studies have provided significant insight into the static and dynamic structure and the function of the upper airway and surrounding soft-tissue structure during wakefulness and sleep. Upper airway imaging modalities primarily include nasopharyngoscopy, cephalometrics, computed tomography (CT), and magnetic resonance (MR) scanning. These imaging modalities have been used to study the effect of respiration, weight loss, dental appliances, and upper airway surgery on the upper airway. MR imaging and CT have allowed the quantification of the airway and surrounding soft-tissue structures in three dimensions. Clinical indications for upper airway imaging are evolving for patients treated with dental appliances and upper airway surgery. Controversy exists in the choice of investigations, probably because the best evaluation should combine different techniques. Physical, radiographic, endoscopic, and acoustic assessment could be integrated to understand the degree and the levels of airway reduction and/or obstruction in each patient. This review focuses on cost-effective and easily implemented techniques in daily practice, allowing quality assessment of the anatomy of the pharyngorofacial complex and upper airway and their impact on the development of sleep-related breathing disorders.