Researchers at Shanghai Jiao Tong University (Shanghai, China) have developed a fast way to acquire 3D endoscopic optical coherence tomography (OCT) images. With further development, the approach could be useful for early detection and classification of a wide range of diseases, including gastrointestinal diseases.
The method uses computational approaches that create a full 3D image from incomplete data. In the researchers' paper that describes the work, they report that useful 3D images could be constructed using 40% less data than traditional 3D OCT approaches, which would decrease imaging time by 40%.
"Although 3D OCT images are very useful for medical diagnosis, the significant amounts of imaging data they require limits imaging speed," explains research team leader Jigang Wu of Shanghai Jiao Tong University. "Our new method solves this problem by forming 3D images from much less data."
Creating 3D OCT images with current methods requires a data-intensive process of stitching together a series of 2D images taken at equal measurements. In the new work, the researchers used a method known as sparse sampling to acquire considerably fewer 2D images and then applied compressive sensing algorithms to fill in the missing information needed to create 3D images.
The researchers tested the method using a magnetic-driven scanning OCT probe to image inside of an extracted pigeon trachea. The probe, which the team developed previously, uses an externally driven tiny magnet to scan 360°. The design minimizes the OCT scanning mechanisms enough to fit inside a 1.4-mm-diameter device.
Creating 3D images of a 2 mm portion of the human trachea would typically require imaging every 10 µm to obtain 200 image frames. Using sparse sampling, the researchers acquired 120 frames at random positions ranging from 0 to 2 mm and then used the compressive sensing algorithms to create 3D images.
"Our tests verified that a greatly reduced amount of experimental data can be used to reconstruct reasonable 3D OCT images," Wu says. "After we perform enough experiments to demonstrate that our probe and imaging method are useful for observing malignant features, our technique will be ready for clinical trials."
The researchers plan to use their approach to image additional biological samples related to specific diseases. They also plan to improve the endoscopic OCT probe so that it will be more robust in a variety of situations and in the context of repeated contact with biological tissues.
Full details of the work appear in the journalApplied Optics.