- 标题
- 摘要
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- 实验方案
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Early Detection of Cerebral Infarction With Middle Cerebral Artery Occlusion With Functional Near-Infrared Spectroscopy: A Pilot Study
摘要： Background: NIRSIT, a functional near-infrared spectroscopy (fNIRS) device with 204 channels, can measure oxyhemoglobin (HbO2) and deoxyhemoglobin (HbR) in non-pulsatile blood ?ow non-invasively using the absorption difference between HbO2 and HbR at a wavelength of 700–1,000 nm and can display the perfusion status in real time. Objective: We applied NIRSIT to patients with stroke to evaluate the usefulness of NIRSIT as an fNIRS device for the early detection of stroke. Methods: We performed a prospective pilot study in an emergency department (ED). Adult patients who had suspected symptoms and signs of stroke within 12 h of the ?rst abnormal time and who underwent intravenous thrombolysis (IVT) or intra-arterial thrombectomy with acute middle cerebral artery (MCA) or internal carotid artery (ICA) infarction were enrolled. NIRSIT was applied to the patients before the imaging study, and the perfusion status of the brain was displayed in real time at the bedside. We compared the NIRSIT results with the mean transit time (MTT) map from perfusion computed tomography (PCT) and the time-to-peak (TTP) map from perfusion-weighted magnetic resonance imaging (PWI). Results: Six male and three female patients were enrolled, and the median age was 74 years. The most common symptom was unilateral extremity weakness (77.8%), followed by dysarthria (33.3%) and aphasia (11.1%). The median National Institutes of Health Stroke Scale (NIHSS) score was 17. All cases of MCA infarction showed different cerebral oxygen saturation values between bilateral lobes of the brain in fNIRS imaging, and these values matched the PCT and PWI results. Conclusions: The brain hemisphere with low oxygen saturation on fNIRS showed hypoperfusion on PCT or PWI. The fNIRS device could be useful in assessing the perfusion status of the brain and detecting MCA or ICA infarction in real time at the bedside.
关键词： middle cerebral artery,magnetic resonance imaging,computed tomography,perfusion,cerebral infarction
更新于2025-09-23 15:21:01
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Spatial Prediction of Undersampled Electromagnetic Fields
摘要： Pneumatic devices require tight tolerances to keep them leak-free. Specialized companies offer various off-the-shelf devices, while these work well for many applications, there are also situations where custom design and production of pneumatic parts are desired. Cost efficiency, design flexibility, rapid prototyping, and MRI compatibility requirements are reasons why we investigated a method to design and produce different pneumatic devices using a laser cutter from acrylic, acetal, and rubber-like materials. The properties of the developed valves, pneumatic cylinders, and stepper motors were investigated. At 4-bar working pressure, the 4/3-way valves are capable of 5-Hz switching frequency and provide at most 22-L/min airflow. The pneumatic cylinder delivers 48 N of force, the acrylic stepper motor 30 N. The maximum switching frequency over 6-m long transmission lines is 4.5 Hz, using 2-mm tubing. A MRI-compatible robotic biopsy system driven by the pneumatic stepper motors is also demonstrated. We have shown that it is possible to construct pneumatic devices using laser-cutting techniques. This way, plastic MRI-compatible cylinders, stepper motors, and valves can be developed. Provided that a laser-cutting machine is available, the described pneumatic devices can be fabricated within hours at relatively low cost, making it suitable for rapid prototyping applications.
关键词： pneumatic systems,Biopsy,magnetic resonance imaging,medical robotics,pneumatic actuators
更新于2025-09-23 15:19:57
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CT/MRI-Guided Synergistic Radiotherapy and X-ray Inducible Photodynamic Therapy Using Tb-Doped Gd-W-Nanoscintillators
摘要： The use of X-rays instead of UV/Vis light to trigger photodynamic therapy, named X-ray inducible photodynamic therapy, holds tremendous promise due to a high penetration capacity in tissues and is worthy of in-depth study. In this study, a novel multifunctional nanoagent based on Merocyanine 540-coupled Gd2(WO4)3:Tb nanoscintillators and the vitalization of its abilities for dual-modal computed tomography and the magnetic-resonance-imaging-guided synergistic radio-/X-ray inducible photodynamic therapy of tumors is reported. Synergistic therapies show a higher tumor growth inhibition efficiency at a lower X-ray dose than radiotherapy alone. Through this proof-of-concept work, a way to tactfully understand and utilize nanoscintillators for cancer theranostics is shown.
关键词： nanoscintillators,radiotherapy,magnetic resonance imaging,computed tomography,X-ray inducible photodynamic therapy
更新于2025-09-19 17:15:36
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Features of Undiagnosed Breast Cancers at Screening Breast MR Imaging and Potential Utility of Computer-Aided Evaluation
摘要： Objective: To retrospectively evaluate the features of undiagnosed breast cancers on prior screening breast magnetic resonance (MR) images in patients who were subsequently diagnosed with breast cancer, as well as the potential utility of MR-computer-aided evaluation (CAE). Materials and Methods: Between March 2004 and May 2013, of the 72 consecutive pairs of prior negative MR images and subsequent MR images with diagnosed cancers (median interval, 32.8 months; range, 5.4–104.6 months), 36 (50%) had visible findings (mean size, 1.0 cm; range, 0.3–5.2 cm). The visible findings were divided into either actionable or underthreshold groups by the blinded review by 5 radiologists. MR imaging features, reasons for missed cancer, and MR-CAE features according to actionability were evaluated. Results: Of the 36 visible findings on prior MR images, 33.3% (12 of 36) of the lesions were determined to be actionable and 66.7% (24 of 36) were underthreshold; 85.7% (6 of 7) of masses and 31.6% (6 of 19) of non-mass enhancements were classified as actionable lesions. Mimicking physiologic enhancements (27.8%, 10 of 36) and small lesion size (27.8%, 10 of 36) were the most common reasons for missed cancer. Actionable findings tended to show more washout or plateau kinetic patterns on MR-CAE than underthreshold findings, as the 100% of actionable findings and 46.7% of underthreshold findings showed washout or plateau (p = 0.008). Conclusion: MR-CAE has the potential for reducing the number of undiagnosed breast cancers on screening breast MR images, the majority of which are caused by mimicking physiologic enhancements or small lesion size.
关键词： False negative breast cancer,Computer-aided evaluation,Magnetic resonance imaging
更新于2025-09-19 17:15:36
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CT/MRI-Guided Synergistic Radiotherapy and X-ray Inducible Photodynamic Therapy Using Tb-Doped Gd-W-Nanoscintillators
摘要： The use of X-rays instead of UV/Vis light to trigger photodynamic therapy, named X-ray inducible photodynamic therapy, holds tremendous promise due to a high penetration capacity in tissues and is worthy of in-depth study. In this study, a novel multifunctional nanoagent based on Merocyanine 540-coupled Gd2(WO4)3:Tb nanoscintillators and the vitalization of its abilities for dual-modal computed tomography and the magnetic-resonance-imaging-guided synergistic radio-/X-ray inducible photodynamic therapy of tumors is reported. Synergistic therapies show a higher tumor growth inhibition efficiency at a lower X-ray dose than radiotherapy alone. Through this proof-of-concept work, a way to tactfully understand and utilize nanoscintillators for cancer theranostics is shown.
关键词： magnetic resonance imaging,nanoscintillators,computed tomography,X-ray inducible photodynamic therapy,radiotherapy
更新于2025-09-19 17:15:36
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[IEEE 2018 7th European Workshop on Visual Information Processing (EUVIP) - Tampere, Finland (2018.11.26-2018.11.28)] 2018 7th European Workshop on Visual Information Processing (EUVIP) - Automatic 3D Detection and Segmentation of Head and Neck Cancer from MRI Data
摘要： A novel algorithm for automatic head and neck 3D tumour segmentation from magnetic resonance imaging (MRI) is presented. The proposed algorithm pre-processes the MRI data slices to enhance quality and reduce artefacts. An intensity standardisation process is performed between slices, followed by cancer region segmentation of central slice, to get the correct intensity range and rough location of tumour regions. Fourier interpolation is applied to create isotropic 3D MRI volume. A new location-constrained 3D level set method segments the tumour from the interpolated MRI volume. The proposed algorithm is tested on real MRI data. The results show that the novel 3D tumour volume extraction algorithm has an improved dice score and F-measure when compared to the previous 2D and 3D segmentation method.
关键词： fuzzy clustering,magnetic resonance imaging,Fourier interpolation,head and neck cancer,3D level set method
更新于2025-09-19 17:15:36
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Theranostic liposomes as a bimodal carrier for magnetic resonance imaging contrast agent and photosensitizer
摘要： The present study is focused on the development of liposomes bearing gadolinium chelate (GdLip) providing two functionalities for magnetic resonance imaging (MRI) and photodynamic therapy of cancer. A lipid derivative of gadolinium(III) diethylenetriamine pentaacetic acid salt (GdDTPA1) was inserted in the liposomal membrane and served as MRI contrast agent whereas a zinc phthalocyanine (ZnPc) was used as a model photosensitizer. In addition to conventional liposomes, pegylated lipids were used for the preparation of 'stealth' liposomes. The characterization of different GdLip formulations involved evaluation of the liposomes size by nanoparticle tracking analysis, thermal phase behavior by differential scanning calorimetry and ZnPc-mediated singlet oxygen production. Furthermore, relaxivity measurements were performed as well as cytotoxicity and photodynamic activity against cancerous and normal cell lines was studied. Size and thermal behavior were only slightly influenced by GdLip composition, however it distinctly affected singlet oxygen production of ZnPc-loaded GdLip. The quantum yields of singlet oxygen generation by zinc phthalocyanine incorporated in GdLip containing cationic or/and pegylated lipids were smaller than those obtained for non-pegylated carriers with L-α-phosphatidylglycerol. In general, all formulations of GdLip, irrespectively of composition, were characterized by relaxivities higher than those of commercially used contrast agents (e.g. Magnevist?). NMR study has shown that the incorporation of ZnPc into the formulations of GdLip increases the relaxation parameters r1 and r2, compared to the values for the non-loaded vesicles. GdDTPA1 did not influence the photodynamic activity of ZnPc against HeLa cells.
关键词： Liposomes,Phthalocyanines,Theranostic,Photodynamic therapy,Magnetic resonance imaging
更新于2025-09-19 17:15:36
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Indoor and Outdoor Test Results for "DUSST", a Low-Cost, Low-Maintenance PV Soiling Sensor
摘要： Pneumatic devices require tight tolerances to keep them leak-free. Specialized companies offer various off-the-shelf devices, while these work well for many applications, there are also situations where custom design and production of pneumatic parts are desired. Cost efficiency, design flexibility, rapid prototyping, and MRI compatibility requirements are reasons why we investigated a method to design and produce different pneumatic devices using a laser cutter from acrylic, acetal, and rubber-like materials. The properties of the developed valves, pneumatic cylinders, and stepper motors were investigated. At 4-bar working pressure, the 4/3-way valves are capable of 5-Hz switching frequency and provide at most 22-L/min airflow. The pneumatic cylinder delivers 48 N of force, the acrylic stepper motor 30 N. The maximum switching frequency over 6-m long transmission lines is 4.5 Hz, using 2-mm tubing. A MRI-compatible robotic biopsy system driven by the pneumatic stepper motors is also demonstrated. We have shown that it is possible to construct pneumatic devices using laser-cutting techniques. This way, plastic MRI-compatible cylinders, stepper motors, and valves can be developed. Provided that a laser-cutting machine is available, the described pneumatic devices can be fabricated within hours at relatively low cost, making it suitable for rapid prototyping applications.
关键词： pneumatic systems,Biopsy,magnetic resonance imaging,medical robotics,pneumatic actuators
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Strong voltage-boost effect in two-step photon-up conversion solar cells
摘要： Single-image super resolution is a process of obtaining a high-resolution image from a set of low-resolution observations by signal processing. While super resolution has been demonstrated to improve image quality in scaled down images in the image domain, its effects on the Fourier-based image acquisition technique, such as MRI, remains unknown. We performed high-resolution ex vivo late gadolinium enhancement (LGE) magnetic resonance imaging (0.4 × 0.4 × 0.4 mm3) in postinfarction swine hearts (n = 24). The swine hearts were divided into the training set (n = 14) and the test set (n = 10), and in all hearts, low-resolution images were simulated from the high-resolution images. In the training set, super-resolution dictionaries with pairs of small matching patches of the high- and low-resolution images were created. In the test set, super resolution recovered high-resolution images from low-resolution images using the dictionaries. The same algorithm was also applied to patient LGE (n = 4) to assess its effects. Compared with interpolated images, super resolution significantly improved basic image quality indices (P < 0.001). Super resolution using Fourier-based zero padding achieved the best image quality. However, the magnitude of improvement was small in images with zero padding. Super resolution substantially improved the spatial resolution of the patient LGE images by sharpening the edges of the heart and the scar. In conclusion, single-image super resolution significantly improves image errors. However, the magnitude of improvement was relatively small in images with Fourier-based zero padding. These findings provide evidence to support its potential use in myocardial scar imaging.
关键词： magnetic resonance imaging,Image processing,image quality,myocardial scar
更新于2025-09-19 17:13:59
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Her2-Functionalized Gold-Nanoshelled Magnetic Hybrid Nanoparticles: a Theranostic Agent for Dual-Modal Imaging and Photothermal Therapy of Breast Cancer
摘要： Targeted theranostic platform that integrates multi-modal imaging and therapeutic function is emerging as a promising strategy for earlier detection and precise treatment of cancer. Herein, we designed targeted gold-nanoshelled poly (lactic-co-glycolic acid) (PLGA) magnetic hybrid nanoparticles carrying anti-human epidermal growth factor receptor 2 (Her2) antibodies (Her2-GPH NPs) for dual-modal ultrasound (US)/magnetic resonance (MR) imaging and photothermal therapy of breast cancer. The agent was fabricated by coating gold nanoshell around PLGA nanoparticles co-loaded with perfluorooctyl bromide (PFOB) and superparamagnetic iron oxide nanoparticles (SPIOs), followed by conjugating with anti-Her2 antibodies. Cell-targeting studies demonstrated receptor-mediated specific binding of the agent to Her2-positive human breast cancer SKBR3 cells, and its binding rate was significantly higher than that of Her2-negative cells (P < 0.001). In vitro, the agent had capabilities for contrast-enhanced US imaging as well as T2-weighted MR imaging with a relatively high relaxivity (r2 = 441.47 mM?1 s?1). Furthermore, the Her2 functionalization of the agent prominently enhanced the US/MR molecular imaging effect of targeted cells by cell-specific binding. Live/dead cell assay and targeted photothermal cytotoxicity experiments confirmed that Her2-GPH NPs could serve as effective photoabsorbers to specifically induce SKBR3 cell death upon near-infrared laser irradiation. In summary, Her2-GPH NPs were demonstrated to be novel targeted theranostic agents with great potential to facilitate early non-invasive diagnosis and adjuvant therapy of breast cancer.
关键词： Anti-Her2 antibody,Photothermal therapy,Ultrasound imaging,Magnetic resonance imaging,Theranostic agent,Breast cancer
更新于2025-09-16 10:30:52