Diagnosing sinusitis remains a challenge for primary care physicians. There is a need for a simple, office-based technique to aid in the diagnosis of sinusitis without the cost and radiation risk of conventional radiologic imaging. We designed a low-cost near-infrared (NIR) device to transilluminate the maxillary sinuses. The use of NIR light allows for greater interrogation of deep-tissue structures as compared to visible light. NIR imaging of 21 patients was performed and compared with computed tomography (CT) scans. Individual maxillary sinuses were scored on a scale from 0 to 2 based on their degree of aeration present on CT and similarly based on the NIR signal penetration into the maxilla on NIR images. Our results showed that air-filled and fluid/tissue-filled spaces can be reasonably distinguished by their differing NIR signal penetration patterns, with average NIR imaging scores for fluid-filled maxillary sinuses (0.93±0.78, n=29) significantly lower than those for normal maxillary sinuses (1.62±0.57, n=13) (p=0.003). NIR imaging of the sinuses is a simple, safe, and cost-effective modality that can potentially aid in the diagnosis of sinusitis. Long-term, significant device refinement and large clinical trials will be needed to determine the diagnostic accuracy of this technique.
Though sinusitis is a significant health problem, it remains a challenging diagnosis for many physicians mainly because of its vague, non-specific symptomology. As such, physicians must often rely on x-rays and CT, which are not only costly but also expose the patient to ionizing radiation. As an alternative to these methods of diagnosis, our laboratory constructed a near infrared (NIR) transillumination system to image the paranasal maxillary sinuses. In contrast to the more conventional form of transillumination, which uses visible light, NIR transillumination uses light with a longer wavelength which is less attenuated by soft tissues, allowing increased signal intensity and tissue penetration. Our NIR transillumination system is low-cost, consisting of a light source containing two series of light emitting diodes, which give off light at wavelengths of 810 nm and 850 nm, and a charge coupled device (CCD) camera sensitive to NIR light. The light source is simply placed in the patient’s mouth and the resultant image created by the transmittance of NIR light is captured with the CCD camera via notebook PC. Using this NIR transillumination system, we imaged the paranasal maxillary sinuses of both healthy patients (n=5) and patients with sinus disease (n=12) and compared the resultant findings with conventional CT scans. We found that air and fluid/tissue-filled spaces can be reasonably distinguished by their differing NIR opacities. Based on these findings, we believe NIR transillumination of the paranasal sinuses may provide a simple, safe, and cost effective modality in the diagnosis and management of sinus disease.