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- 2017
- spectral reconstruction
- interference
- polarization
- transform
- imaging spectrometer
- Optoelectronic Information Science and Engineering
- BITTT
- Zhejiang University
- Guilin University of Aerospace Technology
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Gadolinium Doping Enhances the Photoacoustic Signal of Synthetic Melanin Nanoparticles: A Dual Modality Contrast Agent for Stem Cell Imaging.
摘要： In this paper we show that gadolinium-loaded synthetic melanin nanoparticles (Gd(III)-SMNPs) exhibit up to a 40-fold enhanced photoacoustic signal intensity relative to synthetic melanin alone and higher than other metal-chelated SMNPs. This property makes these materials useful as dual labelling agents because Gd(III)-SMNPs also behave as magnetic resonance imaging (MRI) contrast agents. As a proof-of-concept, we used these nanoparticles to label human mesenchymal stem cells (hMSCs). Cellular uptake was confirmed with bright field optical and transmission electron microscopy. The Gd(III)-SMNP labeled stem cells continued to express the stem cell surface markers CD73, CD90, and CD105 and proliferate. The labeled stem cells were subsequently injected intramyocardially in mice, and the tissue was observed by photoacoustic and MR imaging. We found the photoacoustic signal increased as cell number increased (R2 = 0.96) indicating that such an approach could be employed to discriminate between stem cells populations with a limit of detection of 2.3 x 104 cells in in vitro tests. This multimodal photoacoustic/MRI approach combines the excellent temporal resolution of photoacoustics with the anatomic resolution of MRI.
关键词： Photoacoustic Signal,Stem Cell Imaging,Gadolinium,Dual Modality Contrast Agent,Synthetic Melanin Nanoparticles
更新于2025-09-04 15:30:14
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Exosome-like Nanozyme Vesicles for H2O2-responsive Catalytic Photoacoustic Imaging of Xenograft Nasopharyngeal Carcinoma
摘要： Photoacoustic imaging (PAI) is an attractive imaging modality, which is promising for clinical cancer diagnosis due to its advantages on deep tissue penetration and fine spatial resolution. However, few tumor catalytic/responsive PAI strategies are developed. Here, we design an exosome-like nanozyme vesicle for in vivo H2O2-responsive PAI of nasopharyngeal carcinoma (NPC). The intrinsic peroxidase-like activity of graphene quantum dot nanozyme (GQDzyme) effectively converts the 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) into its oxidized form in the presence of H2O2. The oxidized ABTS exhibits strong near-infrared (NIR) absorbance, rendering it to be an ideal contrast agent for PAI. Thus, GQDzyme/ABTS nanoparticle is a novel type of catalytic PAI contrast agent which is sensitive to H2O2 produced from NPC cells. Furthermore, we develop an approach to construct exosome-like nanozyme vesicle via biomimetic functionalization of GQDzyme/ABTS nanoparticle with natural erythrocyte membrane modified with folate acid. In vivo animal experiments demonstrated that, this exosome-like nanozyme vesicle effectively accumulated in NPC and selectively triggered catalytic PAI for NPC. In addition, our nanozyme vesicle exhibits excellent biocompatibility and stealth ability for long blood circulation. Together, we demonstrate that GQDzyme/ABTS based exosome-like nanozyme vesicle is an ideal nanoplatform for developing deep-tissue tumor-targeted catalytic PAI in vivo.
关键词： photoacoustic imaging,nasopharyngeal carcinoma,H2O2-responsive,graphene quantum dot nanozyme,exosome-like vesicle,erythrocyte membranes
更新于2025-09-04 15:30:14
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Hilbert Curve-Based Metasurface to Enhance Sensitivity of Radio Frequency Coils for 7-T MRI
摘要： In this paper, we propose a compact, lightweight, and easy-to-fabricate Hilbert curve-based metasurface resonator that can effectively increase the sensitivity (radio frequency (RF) field intensity) and penetration depth of an RF coil for 7-T magnetic resonance imaging scanner. A circuit model is proposed to accurately calculate the resonance frequency of Hilbert curve resonators of different orders. A single element of a transverse electromagnetic (EM) coil was used for this paper. The increase in the field sensitivity introduced by the proposed metasurface to an RF coil was successfully demonstrated through simulations and experiments. The EM field produced by the RF coil is redistributed due to the presence of the proposed metasurface. The key feature of the proposed structure is its significant increase in the penetration depth of magnetic fields into the imaging volume. An enhancement of the magnetic field by more than four times was observed at 13.5 cm away from the coil experimentally. Flexibility for matching the coil integrated with the proposed surface is shown.
关键词： metasurface,magnetic resonance imaging (MRI),radio frequency (RF) coil,Hilbert curve
更新于2025-09-04 15:30:14
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Versatile Catalytic Deoxyribozyme Vehicles for Multimodal Imaging-Guided Efficient Gene Regulation and Photothermal Therapy
摘要： Catalytic deoxyribozyme has great potential for gene regulation, but poor efficiency of the cleavage of mRNA and lack of versatile DNAzyme vehicles remain big challenges for potent gene therapy. By rational designing a diverse vehicle of polydopamine-Mn2+ nanoparticles (MnPDA), we demonstrate that MnPDA has integrated functions as an effective DNAzyme delivery vector, self-generation source of DNAzyme cofactor for catalytic mRNA cleavage, inherent therapeutic photothermal agent, as well as contrast agents for photoacoustic and magnetic resonance imaging. Specifically, the DNAzyme-MnPDA nanosystem protects catalytic deoxyribozyme from degradation and enhances cellular uptake efficiency. In the presence of intracellular glutathione, the nanoparticles are able to in-situ generate free Mn2+ as a cofactor of DNAzyme to effectively trigger catalytic cleavage of mRNA for gene silencing. In addition, the nanosystem shows high photothermal conversion efficiency and excellent stability against photothermal processing and degradation in complex environments. Unlike previous DNAzyme delivery vehicles, this vehicle exhibits diverse functionalities for potent gene regulation, allowing multimodal imaging-guided synergetic gene regulation and photothermal therapy both in vitro and in vivo.
关键词： deoxyribozyme,multimodal imaging,photothermal therapy,DNAzyme,gene therapy
更新于2025-09-04 15:30:14
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Motility-based label-free detection of parasites in bodily fluids using holographic speckle analysis and deep learning
摘要： Parasitic infections constitute a major global public health issue. Existing screening methods that are based on manual microscopic examination often struggle to provide sufficient volumetric throughput and sensitivity to facilitate early diagnosis. Here, we demonstrate a motility-based label-free computational imaging platform to rapidly detect motile parasites in optically dense bodily fluids by utilizing the locomotion of the parasites as a specific biomarker and endogenous contrast mechanism. Based on this principle, a cost-effective and mobile instrument, which rapidly screens ~3.2 mL of fluid sample in three dimensions, was built to automatically detect and count motile microorganisms using their holographic time-lapse speckle patterns. We demonstrate the capabilities of our platform by detecting trypanosomes, which are motile protozoan parasites, with various species that cause deadly diseases affecting millions of people worldwide. Using a holographic speckle analysis algorithm combined with deep learning-based classification, we demonstrate sensitive and label-free detection of trypanosomes within spiked whole blood and artificial cerebrospinal fluid (CSF) samples, achieving a limit of detection of ten trypanosomes per mL of whole blood (~five-fold better than the current state-of-the-art parasitological method) and three trypanosomes per mL of CSF. We further demonstrate that this platform can be applied to detect other motile parasites by imaging Trichomonas vaginalis, the causative agent of trichomoniasis, which affects 275 million people worldwide. With its cost-effective, portable design and rapid screening time, this unique platform has the potential to be applied for sensitive and timely diagnosis of neglected tropical diseases caused by motile parasites and other parasitic infections in resource-limited regions.
关键词： parasitic infections,holographic speckle analysis,trypanosomes,resource-limited settings,deep learning,Trichomonas vaginalis,label-free imaging,motility-based detection
更新于2025-09-04 15:30:14
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Progression of retinitis pigmentosa on multimodal imaging: the PREP‐1 study
摘要： Importance: It is important to establish reliable outcome measures to detect progression in retinitis pigmentosa (RP). Background: To evaluate progression of RP using multimodal imaging, including spectral-domain optical coherence tomography (SD-OCT), fundus autofluorescence (FAF) and microperimetry (MP). Design: Retrospective longitudinal study at a tertiary teaching hospital. Participants: 205 eyes of 106 patients with RP with 1-5 years of follow-up. Methods: Demographics and visual acuity (VA) were recorded, and each modality was graded at baseline and every annual follow-up. SD-OCT was graded for the width of ellipsoid zone (EZ), FAF was graded for the diameter and area of the hyperautofluorescent ring (if present), and MP was graded for mean, central and paracentral sensitivity. Spearman’s correlation was used to measure correlations at baseline. Mixed effects models were used to estimate the annual change of each parameter, adjusted for disease duration. Main outcome measures: Rate of progression. Results: The median VA at baseline was 75 letters and was positively correlated with mean and central sensitivity (r: 0.372 and 0.394; p=0.01 for both). All parameters (except paracentral sensitivity) were strongly correlated with each other (r: 0.673-0.991; p<0.001 for all). The annual rates of change for each parameter were as follows: VA, -2.3 letters (p<0.001); EZ, -151um (p<0.001); ring diameter, -132um (p<0.001); ring area, -0.4mm2 (p<0.001); mean sensitivity, -0.3 dB (p<0.001); central sensitivity, -0.7 dB (p<0.001); paracentral sensitivity, -0.4 dB (p<0.001). Conclusion and relevance: Structural and functional measures are well correlated in RP and can reliable measure disease progression within the course of a year.
关键词： Optical Coherence Tomography,Multimodal Imaging,Microperimetry,Fundus Autofluorescence,Disease Progression
更新于2025-09-04 15:30:14
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Intraoperative detection of blood vessels with an imaging needle during neurosurgery in humans
摘要： Intracranial hemorrhage can be a devastating complication associated with needle biopsies of the brain. Hemorrhage can occur to vessels located adjacent to the biopsy needle as tissue is aspirated into the needle and removed. No intraoperative technology exists to reliably identify blood vessels that are at risk of damage. To address this problem, we developed an “imaging needle” that can visualize nearby blood vessels in real time. The imaging needle contains a miniaturized optical coherence tomography probe that allows differentiation of blood flow and tissue. In 11 patients, we were able to intraoperatively detect blood vessels (diameter, >500 mm) with a sensitivity of 91.2% and a specificity of 97.7%. This is the first reported use of an optical coherence tomography needle probe in human brain in vivo. These results suggest that imaging needles may serve as a valuable tool in a range of neurosurgical needle interventions.
关键词： intracranial hemorrhage,optical coherence tomography,neurosurgery,blood vessel detection,imaging needle
更新于2025-09-04 15:30:14
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Hypercolorimetric multispectral imaging system for cultural heritage diagnostics: an innovative study for copper painting examination
摘要： The aim of this work is to test the application of a new multispectral imaging system, named Hypercolorimetric Multispectral Imaging, on two little 17th century oil paintings on copper in order to support the restoration activities. Hypercolorimetric Multispectral Imaging is a non-invasive, rapid and diagnostic technique that allows in situ accurate and reproducible spectral reflectance measurements between 300 nm and 1000 nm to obtain seven monochromatic very high spatial resolution images (36 megapixels starting from RAW format). The acquired images are transformed into radiometric and colorimetric measurements, consisting of 7 monochromatic images of spectral reflectance and one colorimetric image. All these calibrated images constitute the base for further processing performed through a dedicated software that implements a number of functions. In the present paper, a subset of those functions has been used. Specifically: Principal Component Analysis, spectral clustering, spectral mapping, multiband contrast enhancement and edge detection. Combining calibrated images of different spectral regions acquisitions, it was possible to extract relevant information about the state of conservation of the two copper paintings and further significant details were readable compared with the data coming from each single acquisition. The Hypercolorimetric Multispectral Imaging acquisition process revealed to be fast allowing to be performed during the cleaning stage of the paintings. The imaging nature of the analysis allowed to compare and map different areas of the surfaces producing degradation maps of the painting layers, which represents a precious decision-making tool for conservators.
关键词： copper painting examination,non-invasive technique,cultural heritage diagnostics,restoration support,Hypercolorimetric Multispectral Imaging
更新于2025-09-04 15:30:14
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[ACM Press the 7th International Conference - Cairo, Egypt (2018.05.02-2018.05.04)] Proceedings of the 7th International Conference on Software and Information Engineering - ICSIE '18 - An Interactive Mixed Reality Imaging System for Minimally Invasive Surgeries
摘要： In orthopedic surgery, it is important for physicians to completely understand the three-dimensional (3D) anatomical structures for several procedures. With the current revolution in technology in every aspect of our life, mixed reality in the medical field is going to be very useful. However, medicine has a visualization problem hindering how surgeons operate. The surgeons are required to imagine the actual 3D structure of the patient by looking at multiple 2D slices of the patients’ body. This process is time consuming, exhausting and requires special skill and experience. Moreover, patients and surgeons are exposed to extra x-ray doses. Therefore, it is important to provide the surgeon with a better way to diagnose the patient; a way that is more accurate and locates where the problem is in a faster and more efficient manner. Medical imaging systems usually provide 3D images that can guide interventional clinical procedures. However, it is difficult to map the 3D anatomical structure with real objects. This project investigates and solves this problem by providing a mixed reality technology solution that merges the 3D image with real objects to facilitate the work progress of the surgeon. The proposed solution is an interactive mixed reality (MR) system for minimally invasive surgeries. The system is based on mapping the patient volume scan using computed tomography (CT) or Magnetic Resonance Imaging (MRI) to a 3D model of the patient’s body. The rendered model can be used in MR system to view 3D human structures through a set of wearable glasses.
关键词： mixed reality,volume rendering,medical imaging
更新于2025-09-04 15:30:14
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[ACM Press the 3rd International Conference - Tetouan, Morocco (2018.10.10-2018.10.11)] Proceedings of the 3rd International Conference on Smart City Applications - SCA '18 - Usage of watermarking techniques in medical imaging
摘要： In this paper, we present the usage of watermarking techniques in the medical imaging, watermarking is considered a great solution to protect the personal data of patients during the medical images and telemedicine data exchange. This paper is devised in two parts. The first one is reserved for an overview on image watermarking with a presentation of the most important requirements of watermarking (robustness, imperceptibility and capacity). We offer also the general scheme of watermarking with the two essential phases and different types of attacks. Furthermore, we present a classification of watermarking techniques based on various parameters such as: insertion domain, human perception and detection methods, in the end of the section we display some metrics and benchmarks for analysis the performance of the watermarking technique. The second part is reserved for the usage of watermarking techniques in medical imaging especially for integrity verification, authentication and data hiding, we also discuss a literature review on watermarking techniques for medical image. In addition, we present the concept of telemedicine and telehealth fields and the importance of watermarking in the modern health care.
关键词： telemedicine,e-health,medical imaging,medical image watermarking (MIW),Watermarking
更新于2025-09-04 15:30:14