Diagnostic Imaging Could Improve Ear Infection Diagnosis

The researchers found that middle ear fluid shows strong light absorption between 1,400 and 1,550 nm, enabling facile detection in a model using the SWIR otoscope. The study was published on August 22, 2016, in the Proceedings of the National Academy of Sciences (PNAS).

“The one clear diagnostic sign of an infection in the ear is a buildup of fluid behind the eardrum; but the view through a conventional otoscope can't penetrate deeply enough into the tissues to reveal such buildups,” said study co-author Jessica Carr, MSc, an MIT doctoral student. “A lot of times, it's a fifty-fifty guess as to whether there is fluid there. One of the limitations of the existing technology is that you can't see through the eardrum, so you can't easily see the fluid. But the eardrum basically becomes transparent to our device.”

Visualizing structures deep inside opaque biological tissues is one of the central challenges in biomedical imaging. Optical imaging with visible light provides high resolution and sensitivity; however, scattering and absorption of light by tissue limits the imaging depth to superficial features. SWIR shares many of the advantages of visible imaging, but light scattering in tissue is reduced, providing sufficient optical penetration depth to noninvasively interrogate subsurface tissue features.

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Massachusetts Institute of Technology
University of Connecticut Health Center