Ear imaging

Portable OCT system with handheld probe to visualize the normal and infectious middle ear.

Air pressure-driven movements of the eardrum captured with a handheld probe-based pneumatic OCT system.

Otitis media (or middle ear infection) is any inflammation causing the accumulation of fluid in a normally air-filled middle ear space. Otitis media is an especially common health condition for children and is a leading cause of a physicians visit and antibiotic prescription during childhood. One key diagnostic factor is to determine the presence of a fluid in the middle ear, which is difficult to visually determine using a standard otoscope.

Several systems were developed to better quantify the many presentations of middle ear infection in both children and adult subjects. Acute OM cases are often seen with serous fluid and an inflamed eardrum, whereas in chronic OM cases, the eardrum thickness seems to have returned to normal, but the fluid remains and is often more purulent. A non 2D-scanning but fast-imaging-rate system was later developed to explore the pneumatic deflection of the ear under these same infectious conditions, as the eardrum becomes stiff during infection. Later, it was discovered that middle ear biofilms were a major contributor to chronic ear infections, shown by comparing OCT image to direct sampling of structures adhered to the TM. Biofilm based infections must be treated significantly different than acute ones, and may explain why tympanostomy tubes are so effective at reducing infectious symptoms vs antibiotics in chronic cases.

We have made significant advancements in both hardware and software to help analyze or collect data. A method was devised to create a 3-D map of TM thickness using positioning information gleaned from the CCD images. A sub 10,000$ version of this system was made into a briefcase with off-the-shelf parts, to both reduce the weight, size, and cost of the many components but also retain its functionality. Finally, an AI platform was developed with this system in mind that analyzes the content of imaging data to automatically identify signs of infection in OCT data.

  • Monroy, G. L.; Shelton, R. L.; Nolan, R. M.; Nguyen, C. T.; Novak, M. A.; Hill, M. C.; McCormick, D. T.;Boppart, S. A., Noninvasive depth-resolved optical measurements of the tympanic membrane and middle ear for differentiating otitis media. The Laryngoscope 2015, 125 (8), E276-E282. 
  • Nguyen, C. T.; Jung, W.; Kim, J.; Chaney, E. J.; Novak, M.; Stewart, C. N.; Boppart, S. A., Noninvasive in vivo optical detection of biofilm in the human middle ear. Proceedings of the National Academy of Sciences 2012, 109 (24), 9529-9534.  
  •  Shelton, R.L.; Nolan, R.M.; Monroy G.L.; Paritosh, P.; Novak, M.A.; Porter, R.G.; Boppart, S.A., Quantitative pneumatic otoscopy using a light-based ranging technique. Journal of the Association for Research in Otolaryngology (JARO) 2017, 18:555-568.  
  •  Won, J.; Monroy, G.L.; Huang, P-C; Dsouza, R.; Hill, M.C.; Novak, M.A.; Porter, R.G.; Chaney, E.; Barkalifa, R.; Boppart, S. A., Pneumatic low-coherence interferometry otoscope to quantify tympanic membrane mobility and middle ear pressure. Biomedical Optics Express 2018, 9(2):397-409.

OCT/ Raman imaging

Our portable OCT systems can detect the presence of fluid and biofilms behind the middle ear (structures and fluid), though it cannot discern what kind of bacteria or virus are present. A technique called Raman spectroscopy is one solution that can provide “fingerprint identification” of these pathogens. We are developing a combined Raman-OCT system to detect both middle ear fluid and biofilms as well as determine what type of pathogen caused the infection. This is crucial for physicians to know, as viral infections do not resolve with antibiotics. This will help physicians treat ear infections better and prevent the overuse of antibiotics.    

  • Zhao Y, Monroy GL, You S, Shelton RL, Nolan RM, Tu H, Chaney EJ, Boppart SA. Rapid diagnosis and differentiation of microbial pathogens in otitis media with a combined Raman spectroscopy and low-coherence interferometry probe: toward in vivo implementation. J. Biomedical Optics, 21:107005. 2016.

AI driven solutions for fluid diagnosis

Using our extensive library of imaging data and years of experience in ear diagnostic imaging, a machine-learning platform was developed that can automatically detect the signs of infection in the middle ear. When an OCT image of the ear is taken using one of our portable systems, the software takes approximately 20 seconds to automatically evaluate the data and identify middle ear fluid or biofilms behind the eardrum, or, if the ear appears normal. With further development, this platform can enable any user to have the diagnostic ability of an expert physician. Armed with precise knowledge of the infection in this patient, physicians can prescribe the ideal treatment for each patient. 

  • Monroy GL, Won J, Dsouza R, Pande P, Hill MC, Porter RG, Novak MA, Spillman DR, Boppart SA. Automated classification platform for the identification of otitis media using optical coherence tomography. Nature Digital Medicine, 2:22. 2019.

Ear probes

Nearly everyone has directly experienced or knows someone that has had repeated issues with ear infections. Otitis media, the general clinical name for ear infections, are one of the most common reasons for kids to visit the doctor’s office. Our group has developed an imaging system and handheld imaging probe, based on optical coherence tomography, to visualize the contents of the middle ear noninvasively using infrared light no stronger than sunlight. This imaging system can detect the contents of the middle ear without relying on visualization of the eardrum surface, which is often blocked by earwax or a difficult-to-navigate ear canal. This helps physicians more accurately diagnose and ultimately treat ear infections.

  • Monroy GL, Pande P, Nolan RM, Shelton RL, Porter RG, Novak MA, Spillman DR, Chaney EJ, McCormick DT, Boppart SA. Noninvasive in vivo optical coherence tomography tracking of chronic otitis media in pediatric subjects after surgical intervention. J Biomedical Optics, 22:121614. 2017.

Detecting middle ear biofilms in vivo

Recent studies have shown that there is a correlation between recurrent and/or chronic otitis media and the presence of middle ear biofilm. With our portable, handheld OCT system for primary care imaging, bacterial biofilm was non-invasively observed from human subjects with chronic otitis media. The presence of middle ear biofilm visualized from OCT was microbiologically validated. In addition, the subjects with otitis media undergoing the surgical treatment (myringotomy and tympanostomy tube placement) were longitudinally and intraoperatively observed to assess the efficacy of the treatment based on the presence of middle ear fluid and biofilms. A novel analytical technique was also developed to enhance the detection sensitivity of OCT by quantifying nanometer-scale structural changes in the eardrum and biofilm. Furthermore, the presence of middle ear biofilms determined from OCT has also been correlated to acoustic measurements and showed the unique acoustic response of biofilms in the middle ear system.

OCT image of (A) a normal ear and (B) an ear with recurrent acute otitis media. A microbial infection-related structure is found to adhere to the eardrum and within the middle ear cavity in (B). Digital otoscopy images are inset in each panel. White dashed lines indicate the physical location on the eardrum where OCT scan was taken. Representative confocal laser scanning microscope (CLSM) images of fluorescence in situ hybridization (FISH)-tagged sample from the subject with recurrent otitis media. (C) Components identified with the universal bacteria probe, (D) H. influenzae, one of the primary bacteria strains in otitis media, (E) nuclei stain, and (F) overlay of the channels reveals the presence of bacteria dispersed throughout the sample.  

  • Nguyen CT, Jung W, Kim J, Chaney EJ, Novak M, Stewart CN, Boppart SA. Non-invasive in vivo optical detection of biofilm in the human middle ear. Proceedings of the National Academy of Sciences, USA, 109:9529-9534. 2012.
  • Nguyen CT, Tu H, Chaney EJ, Stewart CN, Boppart SA.   Non-invasive optical interferometry for the assessment of biofilm growth in the middle ear.   Biomedical Optics Express, 1:1104-1116. 2010.
  • Monroy GL, Pande P, Nolan RM, Shelton RL, Porter RG, Novak MA, Spillman DR, Chaney EJ, McCormick DT, Boppart SA. Noninvasive in vivo optical coherence tomography tracking of chronic otitis media in pediatric subjects after surgical intervention. J Biomedical Optics, 22:121614. 2017.
  • Monroy GL, Hong W, Khampang P, Porter RG, Novak MA, Spillman DR, Barkalifa R, Chaney EJ, Kerschner JE, Boppart SA. Direct analysis of pathogenic structures affixed to the eardrum during chronic otitis media. Otolaryngology-Head and Neck Surgery, 159:117-126. 2018.
  • Dsouza R, Won J, Monroy GL, Hill MC, Porter RG, Novak MA, Boppart SA. In vivo detection of nanometer-scale structural changes of the human tympanic membrane in otitis media. Scientific Reports, 8:8777. 2018.
  • Won J, Monroy GL, Spillman DR Jr, Huang P-C, Hill MC, Novak MA, Porter RG, Chaney EJ, Barkalifa R, Boppart SA. Assessing the effect of middle ear effusions on wideband acoustic immittance using optical coherence tomography. Ear and Hearing, 41:811-824, 2020.