When a person suffers from chronic ear infections the culprit may be a film of bacteria or other microorganisms that builds up behind the eardrum, not unlike dental plaque on unbrushed teeth. Antibiotics are not always effective against this so-called biofilm, so it helps doctors greatly to know whether it is present before prescribing a course of treatment. Whereas conventional scopes aren't able to see beyond the surface of the eardrum, a team of researchers from the University of Illinois has developed a new tool that can shed some light on the situation.

The device uses a non-invasive imaging system called optical coherence tomography (OCT) to collect high-resolution, three-dimensional tissue images from beams of light sent into the ear canal. The system can scan through the eardrum to any biofilm behind it. The researchers, who liken the process to ultrasound imaging that uses light instead of sonic waves, described their work last week in the online Early Edition of the journal Proceedings of the National Academy of Sciences.

The light scatters and reflects from the tympanic membrane—which separates the external ear from the middle ear—as well as any biofilm that might be behind the membrane. The researchers measure this reflection to determine whether a biofilm is present as well as its thickness and position against the eardrum.

The research team, led by University of Illinois electrical and computer engineering professor Stephen Boppart, tested their ear OCT device at Carle Foundation Hospital in Urbana, Ill. There they scanned patients with diagnosed chronic ear infections, as well as patients with normal ears. The device identified biofilms in all patients with chronic infections, while none of the normal ears showed evidence of biofilms, according to the researchers.

A closer study of ear infections, the most common conditions that pediatricians treat, could lead to a better understanding of the relationship between biofilms and hearing loss. Boppart and his team also plan to adapt their OCT technique to other areas of medicine with the hope that such imaging technology can be useful in diagnosing health problems originating in the eyes, mouth, nose or skin.

Images courtesy of L. Brian Stauffer and Stephen Boppart