Dynamic full-field optical coherence tomography as complementary tool in fungal diagnostics

Dynamic full-field optical coherence tomography for live-cell imaging and growth-phase monitoring in Aspergillus fumigatus

“…As previously described ( Ghouali et al., 2015 ; Maldiney et al., 2020 ; Maldiney et al., 2022 ), D-FF-OCT images were acquired at room temperature with the Light-CT Scanner apparatus accessible at Langevin Institute (LLTech – Aquyre Biosciences). As described in Supplementary Figure S1 and Supplementary Table , the system associates a conventional halogen light source with short temporal coherence length and a set of 10× water immersion microscope objectives with a numerical aperture of 0.3 in a so-called Linnik configuration to reach a final axial and transverse resolution of approximately 1–1.5 µm.…”

“…A contrast-based ImageJ protocol called the “Plot Profile” function allowed length measurements of each fungal compartment for both standard and dynamic contrast images. Finally, as stated in our previous study regarding the specific analysis of D-FF-OCT images ( Maldiney et al., 2022 ), a fast Fourier transform program was used to study the time series corresponding to each pixel behavior. The power spectrum density was split into three parts of equal energy, each matching one of the three main colors of the composite RGB image.…”

“…This confirms the importance of both microscopic examination and histopathology as gold standards for the classification of the proven IFIs ( Donnelly et al., 2020 ). Recently, our group introduced the first results demonstrating the use of dynamic full-field optical coherence tomography (D-FF-OCT) as a complementary tool in fungal diagnostics ( Maldiney et al., 2022 ).…”

“…When applied to the observation of different filamentous fungal species, D-FF-OCT makes it possible to identify multiple intracellular compartments with a definition approaching that of conventional microscopy. It can also retrieve novel metabolic information in relation to fungal subcellular dynamics ( Maldiney et al., 2022 ). Contrary to our previous study, which only described D-FF-OCT preliminary images for three different fungal species, the present work intends to demonstrate how D-FF-OCT may serve live-cell imaging and monitoring of fungal growth stages by focusing on A. fumigatus .…”

Dynamic contrast optical coherence tomography (DyC-OCT) for label-free live cell imaging

“…Figure 2b compares OCT, DyC-OCT, and histology images of benign breast lobules and invasive breast tissue, where DyC-OCT dramatically enhances the contrast of OCT, and reports a high diagnostic accuracy 40 . DyC-OCT has also demonstrated the potential of fungal infection diagnosis to visualize 3D structures of Nannizzia gypsea, Aspergillus fumigatus, and Rhizopus arrhizus 41 . Overall, DyC-OCT can benefit disease diagnosis by enhancing cellular dynamic contrast to reveal changes in morphological features.…”