Visualization of neuritic plaques in Alzheimer’s disease by polarization-sensitive optical coherence microscopy

Developers

Bernhard Baumann, Adelheid Woehrer, Gabor G. Kovacs, Christoph K. Hitzenberger et al.

Description of the technology

One major hallmark of Alzheimer’s disease (AD) and cerebral amyloid angiopathy (CAA) is the deposition of extracellular senile plaques and vessel wall deposits composed of amyloid-beta (Aβ). In AD, degeneration of neurons is preceded by the formation of Aβ plaques, which show different morphological forms. Most of them are birefringent owing to the parallel arrangement of amyloid fibrils.

This technology provides polarization sensitive optical coherence microscopy (PS-OCM) for imaging mature neuritic Aβ plaques based on their birefringent properties. Formalin-fixed, post-mortem brain samples of advanced stage AD patients were investigated. In several cortical brain regions, neuritic Aβ plaques were successfully visualized in tomographic and three-dimensional (3D) images. Cortical grey matter appeared polarization preserving, whereas neuritic plaques caused increased phase retardation. Consistent with the results from PS-OCM imaging, the 3D structure of senile Aβ plaques was computationally modelled for different illumination settings and plaque sizes. Furthermore, the birefringent properties of cortical and meningeal vessel walls in cerebral amyloid angiopathy were investigated in selected samples. Significantly increased birefringence was found in smaller vessels. Overall, these results provide evidence that PS-OCM is able to assess amyloidosis based on intrinsic birefringent properties of neuritic Aβ plaques.

Practical application

The technology is highly promising as a diagnostic method for assessing the progression of Alzheimer’s disease on the basis of the state and development of neuritic plaques in the vessels of the brain. The method is suitable for use in practical medicine and experimental researches.

Laboratories

• Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Vienna (Austria)
• General Hospital and Medical University of Vienna, Institute of Neurology, Vienna (Austria)
• General Hospital and Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Vienna (Austria)

Links

Publications

• Baumann, B. et al. «Visualization of neuritic plaques in Alzheimer’s disease by polarization-sensitive optical coherence microscopy." 7 Scientific Reports (2017): 43477.
• Pircher, M., Hitzenberger, C. K. & Schmidt-Erfurth, U. «Polarization sensitive optical coherence tomography in the human eye." 30 Prog. Retin. Eye Res. (2011): 431–451.
• Götzinger, E. et al. «Polarization maintaining fiber based ultra-high resolution spectral domain polarization sensitive optical coherence tomography." 17 Opt. Express (2009): 22704–22717.