Thin optical fiber optimizes imaging for AD studies

A thin optical fiber shows promise for use in minimally invasive deep tissue studies in brains affected by Alzheimer’s disease, researchers reported in APL Photonics.

A study by Benjamin Lochocki, PhD, a postdoctoral researcher at the Advanced Research Center for Nanolithography at the University of Amsterdam, and colleagues could potentially set the stage for minimally invasive in vivo brain imaging in lab studies and monitoring neuronal activity in patients.

“The ultrathin multimode fiber would easily fit into an acupuncture needle, and we know these needles can be inserted into anyone's body with almost no pain, potentially enabling deep-tissue imaging in real time,” Lochocki said in a release accompanying the study.

According to the press release, increasing image resolution at the subcellular level is challenging due to loss of information from light scrambling. In their study, Lochocki and colleagues address the issue with speckle-based compressive imaging, which exploits the light scrambling of multimode fibers to their advantage.

Typically, light scrambling is addressed through shaping the wavefront of an incident beam to reduce scattering and create a focus beam at the distal end of the fiber, the release stated. This technique has limitations in speed and production.

Speckle-based compressive imaging, however, alters the laser beam entry point, which creates multiple and uncorrelated random speckle patterns at the fiber output. Then, a computer algorithm can reconstruct the image based on the pattern and its collected information.

The authors used this technique to image lipofuscin, age-related fluorescent pigment that accumulates over time as metabolic waste in the soma of the neuron. Abnormal accumulation of lipofuscin may be associated with Alzheimer’s disease progression, although thus far there is little understanding of the process, according to the release.

References:

Newswise. Optical fiber imaging method advances studies of Alzheimer’s disease. https://www.newswise.com/articles/optical-fiber-imaging-method-advances-studies-of-alzheimer-s-disease. Published June 30, 2022. Accessed June 30, 2022.