Imaging human upper airway architecture dynamically using optical coherence tomography

1. INTRODUCTION
Quantitative imaging of the architecture of the human upper airway during sleep is a long standing problem in pulmonary physiology. Calibrated images allowing the objective measurement of key airway dimensions would be valuable in understanding pathologies such as obstructive sleep apnoea, a debilitating condition affecting a significant proportion of the adult population [1]. No existing technology provides all of the key features required to successfully capture dimensionally quantifiable images over long time periods, especially during sleep. X-ray computed tomography (CT) and fluoroscopy involve potentially hazardous ionising radiation. Magnetic resonance imaging (MRI) is expensive, noisy, claustrophobic and incompatible with metallic probes and electrodes. Ultrasound suffers from poor transducer-air coupling, an unavoidable feature in living subjects. The most commonly used technique, endoscopic visualisation, has been widely used in the airway and other large hollow organs to observe anatomical features and structure. However, the measurement of airway dimensions using a nasopharyngoscope requires outlining of the airway wall on the final image – a difficult and subjective task [2]. We have developed a system which uses endoscopic optical coherence tomography (OCT) to take fully calibrated upper airway images. This talk describes the implementation of our hollow organ profiling sensor (HOPS), its application to the human airway, and presents the results to date of our validation studies and preliminary clinical research.