May 2019 cbc.ca
Optical Coherence Tomography offers a non-invasive alternative to diagnose some forms of hearing loss
Researchers at Dalhousie University in Halifax are using existing laser technology in a novel way to diagnose middle ear problems that cause hearing loss, without the need for more invasive procedures. Optical Coherence Tomography allows researchers to create two- and three-dimensional animated images of the middle ear to see whether there's anything irregular that could affect a patient's hearing. "It's a few seconds of tone," Dalhousie researcher Dan MacDougall told CBC's Information Morning as he demonstrated the device in the lab. "It's exciting … All the structures [of the ear] should vibrate in a predictable way and if they're out from normal then we know something's up."
Rob Adamson, an associate professor of biomedical engineering, leads the research team using OCT to diagnose middle-ear conditions that prevent sound waves from reaching the auditory nerve.
"Because we can measure depth we actually see light coming off — not just the eardrum but all the structures behind it," Adamson said.
"And we can take all of those depth-resolved lines that we get and reconstruct an image out of them, and that gives us an image of the full ear in full 2D or 3D."
OCT provides higher resolution images than other current diagnostic tools such as ultrasounds, which bounce sound waves off structures within the body to create an image.
"The big advantage over ultrasound is ultrasound requires that there be either tissue or water in the pathway in order to image and your middle ear is filled with air, said Adamson.
"So ultrasound just can't get images of the middle ear like this without injecting water into the ear, which we tried but it's pretty uncomfortable for the patient.”The use of OCT to diagnose middle-ear conditions is a first.
"This way of imaging has been used in the eye before, but we're one of the first groups to do it in the ear and Dan is actually the first person ever to get a live ear image of himself," said Adamson.
The technology is more widely used to generate cross-sectional pictures of retinas using light waves.
Left is an image of the middle ear taken non-invasively using OCT. On the right is a picture of the same structures in the middle ear taken with a scope after the ear drum was removed.
According to the Canadian Ophthalmological Society's website, it is used to diagnose conditions such as macular degeneration and glaucoma. It can also be used to diagnose eye damage in people who have looked at a solar eclipse.
Adamson said OCT technology is expected to be used for middle-ear diagnoses within the Nova Scotia Health Authority within the next month or so. He said the Massachusetts Eye and Ear infirmary in Boston will also continue researching OCT for use in diagnosing hearing conditions before Adamson's lab applies for Food and Drug Administration approval within the next year.
Adamson said he's looking for PhD and master's students with backgrounds in math, physics or engineering to work on the project.