High dynamic range imaging concept-based signal enhancement method reduced the optical coherence tomography...

Area of Science:

• Ophthalmology
• Biomedical Imaging
• Medical Technology

Background:

• Optical coherence tomography (OCT) is crucial for visualizing ocular structures.
• Image quality in OCT can be significantly affected by signal strength variations.
• Retinal nerve fiber layer (RNFL) thickness measurement is vital for diagnosing glaucoma and other optic neuropathies.

Purpose of the Study:

• To develop and validate a novel signal enhancement method for OCT images using the high dynamic range (HDR) imaging concept.
• To assess the effectiveness of the HDR method in improving image quality and reducing measurement variability in OCT scans.

Main Methods:

• A novel HDR imaging approach was developed by creating three virtual channels (low, medium, high signal components) from OCT data.
• Signal components were normalized and recombined using varying weights.
• The method was tested on time-domain (TD)-OCT and spectral-domain (SD)-OCT images from healthy volunteers, including scans with varying signal strengths and poor quality.

Main Results:

• The HDR method significantly reduced differences in RNFL thickness measurements between good and poor quality TD-OCT scans (from 11.9 μm to 1.7 μm).
• HDR showed effective signal enhancement and RNFL thickness compensation for OCT images with signal strength greater than 4.
• Subjective confirmation of signal enhancement was observed in SD-OCT images.

Conclusions:

• The developed HDR imaging technique successfully restores OCT signal and image quality.
• This method minimizes RNFL thickness discrepancies arising from variable signal levels, bringing them within expected measurement variability.
• The HDR technique is applicable to both TD-OCT and SD-OCT imaging modalities.