Bimodal Approach Using Spectroscopy and Digitial Imaging to Assist Otitis Media Diagnosis

Otitis Media is defined as inflammation of the middle ear region associated with middle ear fluid. This condition typically follows an upper respiratory infection, is commonly misdiagnosed by physicians and can potentially lead to the inappropriate use of antimicrobial agents. [1] This thesis describes the design of a novel medical device that utilized spectroscopy and digital imaging to provide physicians with a unique representation of the middle ear. Published literature has been reviewed to assess the different approaches that researchers have studied to improve the diagnosis of otitis media, where, for example, research conducted by Thorton et al. and Boppart et al. used fluorescence to identify bacteria contained in biofilms.[12,13] In addition, a population study conducted by Jensen et al. determined what the level of diagnostic certainty is in pediatric patients and determined that general practitioners had a diagnostic certainty of 58% in patients under one year of age and 73% certainty in patients over two and a half years of age.[9] Eleven subjects, each with a history of recurrent acute otitis media and requiring myringotomy and ear tube placement, were selected for study in this thesis. All subjects received a digital imaging and spectroscopy examination using the device at the time of surgery. Five excitation and illumination wavelengths were used, including white light, 385-420 nm, 450-470 nm, 520-535 nm, and 640-650 nm as well as fluorescence imaging using 425 nm and 450 nm filters. Each of the chosen wavelengths were emitted into the ear canal and tympanic membrane during a typical otoscopic examination. Signal processing techniques were also applied to isolate various regions of the tympanic membrane using MatLAB to increase the resolution of the anatomical and physiological properties of the tympanic membrane. The spectral readings between the wavelengths of 560 nm and 760 nm were plotted for each subject and were classified according to fluid retention, consistency, and vascularity. In this subject population, eight of the 22 ears were identified to be a noneffusion normal. Reflectance of keratin, cerumen, and bone, with well defined blood vessels and contrast, allowed for better characterization of the middle ear. [8] Reflectance spectra were classified according to fluid consistency and trends were determined for non effusion and effusion patients. Class one spectra were defined as tympanic membrane and canal spectra with a rapid increase in percent reflection between 575 nm and 650 nm and a rapid decrease in percent reflection between 650 nm and 750 nm. Class two spectra were defined as tympanic membrane and canal spectra with a gradual decrease in percent reflection between 575 nm and 800 nm. This novel device was successfully used to detect effusion consistency and color and it will continue to aid in the development of a new diagnostic procedure. It provides a means for the creation of a new diagnostic procedure that may be useful in assisting a physician in making an accurate diagnosis, and as a result, increase the diagnostic certainty