Bone marrow aspiration procedures play an important role in the assessment of patients with blood and marrow diseases, including cancers. Evaluating the adequacy of aspirates, indicated by the presence of bony spicules, is crucial to ensure the procedural success and collection of relevant diagnostic material. Unfortunately, inadequate samples occur in approximately 50 % of cases, requiring patients to undergo repeat procedures. This is particularly problematic for pediatric patients who need to be anesthetized before each procedure. The current gold standard is hematopathologist examination of Giemsa-stained slides, which is time consuming and requires expensive biochemical reagents and trained technicians. Recently, Here we present a portable, LED-based UV microscope designed for real-time inspection of bone marrow aspirates. We discuss results from a clinical trial with pediatric oncology patients demonstrating excellent agreement between UV examination of unstained slides and ground truth pathologist examination of stained slides. Furthermore, we demonstrate whole slide imaging using a previously developed, compact UV microscopy system and automated spicule detection with deep neural networks to work towards point-of-care applications.
Ultraviolet (UV) microscopy of live cells has been challenging due to phototoxicity, with UV radiation affecting cellular components leading to irreversible cell death. Despite this challenge, recent advances in UV light sources and detectors have renewed interest in UV microscopy due to its high resolution and label-free molecular imaging capabilities. Indeed, UV microscopy has been recently demonstrated for a wide variety of cellular imaging applications, including multispectral imaging of cancer tissue sections, cells at varying time scales, and hematological analysis of whole blood cells. While these studies have leveraged UV microscopy to image static samples and cellular dynamics over short periods of time, UV phototoxicity remains a problem during live cell imaging sessions lasting over several hours and longitudinal imaging of a single sample. In this work, we characterize UV-induced photodamage by quantifying the flux required for cell death at notable wavelengths in the deep-UV region. We demonstrate how this flux can vary with cell adherence type using adherent and non-adherent cell lines. We then present fractionation studies conducted over time scales ranging from several hours to days and discuss the ability of cell populations to recover in each case. Finally, we provide viable live-cell imaging frameworks for UV microscopy applications ranging from single multispectral imaging sessions to long-term observation of samples.
Intracellular activity occurs at a wide range of time scales, requiring a multiscale approach for data acquisition and analysis. Current optical techniques used for imaging intracellular dynamics suffer from limited imaging speeds, low biomolecular specificity, or require fluorescent labels which can perturb cellular environments. Deep-ultraviolet (UV) microscopy enables fast, label-free, and quantitative molecular imaging with subcellular resolution. Previously, multispectral deep-UV microscopy has been demonstrated for robust hematology analysis and prostate tissue characterization. In this work, we present deep-UV microscopy as a tool to capture multiscale intracellular dynamics. We discuss our microscope setup and analytical framework using phasor analysis. We show that deep-UV microscopy can characterize multiscale intracellular dynamics in prostate cancer cells and reveals unique activity in cell lines of varying malignancy.
Neutropenia is a blood disorder characterized by an abnormally low number of neutrophils in the bloodstream. This condition signifies an increased risk of infections, and thus can lead to life-threatening medical emergencies in severe cases. Therefore, it is critical to routinely monitor neutrophil counts in cancer patients. However, the current clinical standard-of-care for blood cell enumeration to assess neutropenia relies on complete blood count (CBC) which requires expensive and complex equipment, multiple reagents, and cumbersome procedures, impeding easy and timely access to critical hematological information. Here, we demonstrate the application of a microfluidic device which, along with deep-ultraviolet microscopy, enables stain-free and fixative-free hematological assessment of neutropenia. We demonstrate the capabilities of our approach in detection and staging of neutropenia by imaging samples obtained from healthy donors as well as moderate and severe neutropenia patients while verifying the results against CBC findings. This work has significant implications towards the development of a low-cost, and easy-to-use point-of-care device for tracking neutrophil counts.
Deep Ultraviolet (UV) Microscopy enables high-resolution, quantitative, and label-free imaging of biomolecules. Recently, we have shown that UV microscopy can be used as a tool for simple and fast hematology analysis by providing diagnostically relevant information on morphological and cytogenic properties of various blood cells. We have demonstrated the ability to classify and segment red blood cells, white blood cell subtypes, and platelets via deep learning frameworks and have applied this technique for diagnosis of blood disorders. In this work, we present a compact, low-cost deep-UV microscope capable of performing a rapid complete blood count (CBC). CBCs, one of the most commonly performed medical tests in the United States, provide critical counts of blood components used to monitor and diagnose blood disorders. This device can serve as a point-of-care alternative to modern hematology analyzers by leveraging endogenous biomolecular contrast from UV light to perform label-free hematology analysis. Here we discuss our approach of using simple, low-cost optics and hardware to enable fast and accurate imaging of blood samples. We demonstrate the capability of this system to scan and capture images of whole blood on blood smears and in custom microfluidic devices. We also show that these images can be used to segment, classify, and colorize blood cell subtypes. Lastly, we evaluate the efficacy of our stage translation system by assessing its positioning and translation accuracy.
Purpose: The recent coronavirus disease 2019 (COVID-19) pandemic, which spread across the globe in a very short period of time, revealed that the transmission control of disease is a crucial step to prevent an outbreak and effective screening for viral infectious diseases is necessary. Since the severe acute respiratory syndrome (SARS) outbreak in 2003, infrared thermography (IRT) has been considered a gold standard method for screening febrile individuals at the time of pandemics. The objective of this review is to evaluate the efficacy of IRT for screening infectious diseases with specific applications to COVID-19.
Approach: A literature review was performed in Google Scholar, PubMed, and ScienceDirect to search for studies evaluating IRT screening from 2002 to present using relevant keywords. Additional literature searches were done to evaluate IRT in comparison to traditional core body temperature measurements and assess the benefits of measuring additional vital signs for infectious disease screening.
Results: Studies have reported on the unreliability of IRT due to poor sensitivity and specificity in detecting true core body temperature and its inability to identify asymptomatic carriers. Airport mass screening using IRT was conducted during occurrences of SARS, Dengue, Swine Flu, and Ebola with reported sensitivities as low as zero. Other studies reported that screening other vital signs such as heart and respiratory rates can lead to more robust methods for early infection detection.
Conclusions: Studies evaluating IRT showed varied results in its efficacy for screening infectious diseases. This suggests the need to assess additional physiological parameters to increase the sensitivity and specificity of non-invasive biosensors.
We developed a wearable system for wireless monitoring of oxygenation of deep tissues such as liver and lung during exercise. It is also useful where subcutaneous fat thickness is high. Our system utilizes Continuous Wave Near Infrared Spectroscopy (CW NIRS) with source-detector distances from 10mm to 60mm. This allows us to observe tissues at various depths. To mitigate the interference of the overlaying tissue layers such as skin, fat and muscle, we developed a multi-layer Monte Carlo model for photon diffusion. Flexible structure of our device helps achieve better skin contact and expand its usability to most body parts.
Dynamic Full-Field Optical Coherence Tomography (D-FFOCT) is a high transverse resolution version of OCT that records signal at the output of the interferometer as a movie over a few seconds. Analyzing the temporal variation of the signals reveals intracellular contrast which gives D-FFOCT the capability of identifying dynamic metabolic changes. We use D-FFOCT to identify oxygen induced changes in cellular metabolism at ambient (22%) oxygenation and at hypoxia (1%). Signal strength, calculated as an integral of the raw FFT spectrum, is significantly higher for 1% samples compared to 22% indicating that D-FFOCT is sensitive to changes in cell metabolism.
Working memory (WM) is part of the short-term memory storage in human brain. N-back is a WM task to assess mental workload on the prefrontal cortex (PFC). In this work, we studied how mental workload changes in an N-back task over the length of the experiment. We focused on two task levels of two- and three-back. Examining both hemodynamics and behavioral data (correct answers), we found a significant difference between 2-back and 3-back tasks and a significant difference between the beginning and end of the 3-back task.
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