We present a benchmark pilot study in which high-resolution Full-Field Optical Coherence Tomography (FF-OCT) was used to image human breast tissue and is evaluated to assess its ability to aid the pathologist’s management of intra-operative diagnoses. FF-OCT imaging safety was investigated and agreement between FF-OCT and routinely prepared histopathological images was evaluated. The compact setup used for this study provides 1 µm3 resolution and 200 µm imaging depth, and a 2.25 cm2 specimen is scanned in about 7 minutes. 75 breast specimens were imaged from 22 patients (21 women, 1 man) with a mean age of 58 (range: 25-83). Pathologists blind diagnosed normal/benign or malignant tissue based on FF-OCT images alone, diagnosis from histopathology followed for comparison. The contrast in the FF-OCT images is generated by intrinsic tissue scattering properties, meaning that no tissue staining or preparation is required. Major architectural features and tissue structures of benign breast tissue, including adipocytes, fibrous stroma, lobules and ducts were characterized. Subsequently, features resulting from pathological modification were characterized and a diagnosis decision tree was developed. Using FF-OCT images, two breast pathologists were able to distinguish normal/benign tissue from lesional with a sensitivity of 94% and 90%, and specificity of 75% and 79% respectively.
We present the first full-field optical coherence tomography (FFOCT) device capable of imaging of the human cornea. We obtained images of the epithelial structures, Bowman's layer, sub-basal nerve plexus (SNP), anterior and posterior stromal keratocytes, stromal nerves, Descemet's membrane and endothelial cells with visible nuclei. Images were acquired with a high lateral resolution of 1.7 µm and relatively large field-of-view of 1.26 mm x 1.26 mm - a combination, which, to the best of our knowledge, has not been possible with other human eye imaging methods. The latter together with a contactless operation, make FFOCT a promising candidate for becoming a new tool in ophthalmic diagnostics.
We have evaluated the ability of three commercially available deformable mirrors to compensate the aberrations of the eye using a model for aberrations developed by Thibos, Bradley and Hong. The mirrors evaluated were a 37 actuator membrane mirror and 19 actuator piezo mirror (OKO Technologies) and a 35 actuator bimorph mirror (AOptix Inc). For each mirror, Zernike polynomials and typical ocular aberrated wavefronts were fitted with the mirror modes measured using a Twyman-Green interferometer. The bimorph mirror showed the lowest root mean square error, although the 19 actuator piezo device showed promise if extended to more actuators. The methodology can be used to evaluate new deformable mirrors as they become available.
Background/Aims: Full-field optical coherence tomography (FFOCT) is a new imaging technology that can provide 3D micron-level resolution and is suited for high-resolution imaging of biological tissue. The aim of this study was to evaluate its capacity and potential for imaging human epidermis and dermis and various skin pathologies in ex vivo and in vivo conditions. Methods: Non-fixed and fixed samples of normal and pathological skin and normal in vivo skin were imaged with a FFOCT system and compared to histological slides. Results: The epidermis and adnexae, the collagen bundles of the dermis and the hypodermis could be identified through architectural and cellular details. The pathological structures were distinguished from the normal structures and corresponded to their histopathological organization. Conclusion: FFOCT is a novel technology in the field of skin imaging that has the potential to be a relevant complement to existing non-invasive imaging modalities for clinical and cosmetic applications.
The main applications of adaptive optics are the correction of the effects of atmospheric turbulence on ground-based telescopes and the correction of ocular aberrations in retinal imaging and visual simulation. The requirements for the wavefront corrector, usually a deformable mirror, will depend on the statistics of the aberrations to be corrected; here we compare the spatial statistics of wavefront aberrations expected in these two applications. We also use measured influence functions and numerical simulations to compare the performance of eight commercially available deformable mirrors for these tasks. The performance is studied as a function of the size of the optical pupil relative to the actuated area of the mirrors and as a function of the number of modes corrected. In the ocular case it is found that, with the exception of segmented mirrors, the performance is greatly enhanced by having a ring of actuators outside the optical pupil, as this improves the correction of the pupil edge. The effect is much smaller in the case of Kolmogorov wavefronts. It is also found that a high Strehl ratio can be obtained in the ocular case with a relatively low number of actuators if the stroke is sufficient. Increasing the number of actuators has more importance in the Kolmogorov case, even for the relatively weak turbulence considered here.
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