Detection of an early stage of subglottic edema is vital for airway management and prevention of stenosis, a life-threatening condition in critically ill neonates. As an observer for the task of diagnosing edema in vivo, we investigated spatiotemporal correlation (STC) of full-range optical coherence tomography (OCT) images acquired in the rabbit airway with experimentally simulated edema. Operating the STC observer on OCT images generates STC coefficients as test statistics for the statistical decision task. Resulting from this, the receiver operating characteristic (ROC) curves for the diagnosis of airway edema with full-range OCT in-vivo images were extracted and areas under ROC curves were calculated. These statistically quantified results demonstrated the potential clinical feasibility of the STC method as a means to identify early airway edema.

Recently, full-range optical coherence tomography (OCT) systems have been developed to image the human airway. These novel systems utilize a fiber-based OCT probe which acquires three-dimensional (3-D) images with micrometer resolution. Following an airway injury, mucosal edema is the first step in the body’s inflammatory response, which occasionally leads to airway stenosis, a life-threatening condition for critically ill newborns. Therefore, early detection of edema is vital for airway management and prevention of stenosis. In order to examine the potential of the full-range OCT to diagnose edema, we investigated temporal correlation of OCT images obtained from the subglottic airway of live rabbits. Temporally correlated OCT images were acquired at fixed locations in the rabbit subglottis of either artificially induced edema or normal tissues. Edematous tissue was experimentally modeled by injecting saline beneath the epithelial layer of the subglottic mucosa. The calculated cross temporal correlations between OCT images of normal airway regions show periodicity that correlates with the respiratory motion of the airway. However, the temporal correlation functions calculated from OCT images of the edematous regions show randomness without the periodic characteristic. These in-vivo experimental results of temporal correlations between OCT images show the potential of a computer-based or -aided diagnosis of edema in the human respiratory mucosa with a full-range OCT system.