The nascent technology of ptychography, employed in high-throughput optical imaging, will see progress in both performance and the range of its applications. As this review concludes, we outline several potential paths for future work.
Pathology is increasingly incorporating whole slide image (WSI) analysis as a valuable asset. Whole slide image (WSI) analysis tasks, including WSI classification, segmentation, and retrieval, have benefited from the remarkable performance improvements delivered by recent deep learning methods. Furthermore, WSI analysis is computationally expensive, particularly given the substantial dimensions of the WSIs. All existing analytical approaches invariably demand the complete unpacking of the entire image, a significant barrier to practical application, especially in deep learning-driven workstreams. We present, in this paper, computationally efficient WSIs classification analysis workflows, facilitated by compression domain processing, which can be used with the most advanced WSI classification models. WSI file pyramidal magnification and compression domain features, as accessible through the raw code stream, are leveraged by these approaches. The methods employ features from either compressed or partially decompressed patches to dynamically allocate various decompression depths to the WSIs' constituent patches. The low-magnification level patches are subject to screening by attention-based clustering, which in turn results in varying decompression depths allocated to the high-magnification level patches in diverse locations. The file code stream's compression domain features are utilized to pinpoint a smaller set of high-magnification patches for full decompression, implementing a more refined selection process. After generation, the patches are passed to the downstream attention network for the concluding classification. High zoom level access and full decompression, costly operations, are minimized to optimize computational efficiency. Implementing a decrease in the number of decompressed patches has a significant positive impact on the time and memory usage during the downstream training and inference operations. The remarkable speedup achieved by our approach is 72 times faster, and the memory usage was reduced by 11 orders of magnitude, keeping the resulting model accuracy consistent with the accuracy of the original workflow.
Accurate and continuous blood flow monitoring is paramount for achieving therapeutic success during many surgical operations. Blood flow monitoring through laser speckle contrast imaging (LSCI), a simple, real-time, and label-free optical technique, presents itself as a promising tool, but is hampered by its limitations in generating reproducible quantitative measurements. Multi-exposure speckle imaging (MESI), although an advancement of laser speckle contrast imaging (LSCI), suffers from intricate instrumentation, limiting its applications. We detail the design and fabrication of a compact, fiber-coupled MESI illumination system (FCMESI), substantially smaller and less intricate than previous approaches. Our findings, derived from experiments with microfluidic flow phantoms, establish that the FCMESI system's flow measurement accuracy and repeatability are equivalent to those of standard free-space MESI illumination systems. We also demonstrate, within an in vivo stroke model, that FCMESI can monitor alterations in cerebral blood flow.
Fundus photography is critical for the diagnosis and treatment of ophthalmic conditions. Low contrast images and small field coverage often characterize conventional fundus photography, thereby hampering the identification of subtle abnormalities indicative of early eye disease. The advancement of image contrast and field of view is paramount for accurate early disease diagnosis and effective treatment evaluation. A portable fundus camera with high dynamic range imaging and a broad field of view is the subject of this report. Miniaturized indirect ophthalmoscopy illumination was a crucial component in the creation of a portable nonmydriatic system for capturing wide-field fundus photographs. By employing orthogonal polarization control, the effects of illumination reflectance artifacts were eliminated. selleck chemicals llc By leveraging independent power controls, three fundus images were acquired sequentially and fused to implement HDR function, resulting in enhanced local image contrast. Nonmydriatic fundus photography achieved a 101 eye-angle (67 visual-angle) snapshot field of view. By utilizing a fixation target, the effective field of view was easily expanded to 190 degrees of eye-angle (134 degrees of visual-angle) without requiring any pharmacologic pupillary dilation. The efficacy of high dynamic range imaging was corroborated in both healthy and diseased eyes, juxtaposed against a conventional fundus camera.
Objective assessment of retinal photoreceptor cells, focusing on parameters such as cell diameter and outer segment length, is vital for early, accurate, and sensitive diagnosis and prognosis of neurodegenerative diseases. The living human eye's photoreceptor cells are visualized in three dimensions (3-D) using adaptive optics optical coherence tomography (AO-OCT). Presently, the gold standard for extracting cell morphology from AO-OCT images is the cumbersome manual 2-D marking process. A comprehensive deep learning framework for segmenting individual cone cells in AO-OCT scans is proposed to automate this process and extend to 3-D analysis of the volumetric data. In evaluating cone photoreceptors of healthy and diseased participants, our automated method achieved human-level performance, using three different AO-OCT systems—a spectral-domain and two swept-source point-scanning OCT systems.
Improving intraocular lens power and sizing calculations in cataract and presbyopia treatments hinges upon a precise quantification of the human crystalline lens's full 3-dimensional form. A preceding study detailed a groundbreaking technique for representing the full shape of the ex vivo crystalline lens, referred to as 'eigenlenses,' which demonstrated superior compactness and precision compared to existing state-of-the-art techniques for crystalline lens shape measurement. Eigenlenses are used here to estimate the complete configuration of the crystalline lens in living subjects, using optical coherence tomography images, where access is limited to the information discernible via the pupil. The performance of eigenlenses is measured against preceding techniques in the estimation of entire crystalline lens shapes, emphasizing gains in consistency, dependability, and computational cost effectiveness. Our investigation established that eigenlenses can accurately describe the full range of alterations in the crystalline lens's shape, which are directly impacted by accommodation and refractive error.
Optimized imaging performance for a given application is achieved by TIM-OCT (tunable image-mapping optical coherence tomography), which uses a programmable phase-only spatial light modulator within a low-coherence, full-field spectral-domain interferometer. In a single snapshot, the resultant system, without any moving components, enables high lateral or high axial resolution. Through a multiple-shot acquisition, the system can achieve high resolution in every dimension. TIM-OCT's imaging capabilities were evaluated using both standard targets and biological samples. Along with this, we exhibited the integration of TIM-OCT and computational adaptive optics for the correction of optical aberrations resulting from the sample.
We scrutinize the commercial mounting medium Slowfade diamond to determine its viability as a buffer for STORM microscopy applications. Our findings reveal that this technique, while proving ineffective with the prevalent far-red dyes frequently used in STORM imaging, such as Alexa Fluor 647, demonstrates outstanding performance with various green-excitable fluorophores, including Alexa Fluor 532, Alexa Fluor 555, or the alternative CF 568. Moreover, the possibility of imaging procedures is achievable many months following the placement and refrigeration of the specimens in this setup, providing a convenient approach to preserving samples for STORM imaging, and preserving calibration samples, for example in metrology or educational settings, in particular within imaging facilities.
Cataracts elevate the level of scattered light in the crystalline lens, thereby reducing the contrast of retinal images and impairing vision. The wave correlation of coherent fields, known as the Optical Memory Effect, facilitates imaging through scattering media. Our investigation into the scattering characteristics of extracted human crystalline lenses involves measuring their optical memory effect and other quantifiable scattering metrics, ultimately establishing correlations between these factors. selleck chemicals llc Fundus imaging techniques may be enhanced by this work, along with non-invasive vision correction procedures for cataracts.
The creation of a precise subcortical small vessel occlusion model, suitable for pathological studies of subcortical ischemic stroke, remains inadequately developed. This study's minimally invasive approach, employing in vivo real-time fiber bundle endomicroscopy (FBE), established a subcortical photothrombotic small vessel occlusion model in mice. Our FBF system enabled precise targeting of specific deep brain blood vessels, allowing for simultaneous observation of clot formation and blood flow blockage during photochemical reactions within the targeted vessel. A fiber bundle probe was implanted directly into the anterior pretectal nucleus of the thalamus, situated within the brain of live mice, to achieve a targeted obstruction of the small vessels. Using a patterned laser, photothrombosis was selectively applied, and the dual-color fluorescence imaging allowed visualization of the process. Infarct lesion sizes are measured on day one post-occlusion, using both TTC staining and subsequent histological methods. selleck chemicals llc A subcortical small vessel occlusion model for lacunar stroke was successfully created by the application of FBE to targeted photothrombosis, according to the results.