ABSTRACT
As a vertebrate model animal, larval zebrafish are widely used in neuroscience and provide a unique opportunity to monitor whole-brain activity at the cellular resolution. Here, we provide an optimized protocol for performing whole-brain imaging of larval zebrafish using three-dimensional fluorescence microscopy, including sample preparation and immobilization, sample embedding, image acquisition, and visualization after imaging. The current protocol enables in vivo imaging of the structure and neuronal activity of a larval zebrafish brain at a cellular resolution for over 1 h using confocal microscopy and custom-designed fluorescence microscopy. The critical steps in the protocol are also discussed, including sample mounting and positioning, preventing bubble formation and dust in the agarose gel, and avoiding motion in images caused by incomplete solidification of the agarose gel and paralyzation of the fish. The protocol has been validated and confirmed in multiple settings. This protocol can be easily adapted for imaging other organs of a larval zebrafish.
Subject(s)
Brain , Imaging, Three-Dimensional , Intravital Microscopy , Microscopy, Fluorescence , Neuroimaging , Zebrafish , Animals , Brain/diagnostic imaging , Imaging, Three-Dimensional/instrumentation , Imaging, Three-Dimensional/methods , Neuroimaging/instrumentation , Neuroimaging/methods , Sepharose , Intravital Microscopy/instrumentation , Intravital Microscopy/methodsABSTRACT
One of the primary technical challenges facing magnetoencephalography (MEG) is that the magnitude of neuromagnetic fields is several orders of magnitude lower than interfering signals. Recently, a new type of sensor has been developed - the optically pumped magnetometer (OPM). These sensors can be placed directly on the scalp and move with the head during participant movement, making them wearable. This opens up a range of exciting experimental and clinical opportunities for OPM-based MEG experiments, including paediatric studies, and the incorporation of naturalistic movements into neuroimaging paradigms. However, OPMs face some unique challenges in terms of interference suppression, especially in situations involving mobile participants, and when OPMs are integrated with electrical equipment required for naturalistic paradigms, such as motion capture systems. Here we briefly review various hardware solutions for OPM interference suppression. We then outline several signal processing strategies aimed at increasing the signal from neuromagnetic sources. These include regression-based strategies, temporal filtering and spatial filtering approaches. The focus is on the practical application of these signal processing algorithms to OPM data. In a similar vein, we include two worked-through experiments using OPM data collected from a whole-head sensor array. These tutorial-style examples illustrate how the steps for suppressing external interference can be implemented, including the associated data and code so that researchers can try the pipelines for themselves. With the popularity of OPM-based MEG rising, there will be an increasing need to deal with interference suppression. We hope this practical paper provides a resource for OPM-based MEG researchers to build upon.
Subject(s)
Magnetoencephalography/instrumentation , Neuroimaging/instrumentation , Algorithms , Equipment Design , Head Movements , Humans , Scalp , Signal Processing, Computer-AssistedABSTRACT
Fiber photometry (FP) is an adaptable method for recording in vivo neural activity in freely behaving animals. It has become a popular tool in neuroscience due to its ease of use, low cost, the ability to combine FP with freely moving behavior, among other advantages. However, analysis of FP data can be challenging for new users, especially those with a limited programming background. Here, we present Guided Photometry Analysis in Python (GuPPy), a free and open-source FP analysis tool. GuPPy is designed to operate across computing platforms and can accept data from a variety of FP data acquisition systems. The program presents users with a set of graphic user interfaces (GUIs) to load data and provide input parameters. Graphs are produced that can be easily exported for integration into scientific figures. As an open-source tool, GuPPy can be modified by users with knowledge of Python to fit their specific needs.
Subject(s)
Image Processing, Computer-Assisted/methods , Neuroimaging/instrumentation , Neuroimaging/methods , Photometry/instrumentation , Photometry/methods , Software , Algorithms , Animals , Area Under Curve , Artifacts , Brain/diagnostic imaging , Calcium/chemistry , Computer Graphics , Dopamine/chemistry , Female , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , Neurosciences , Programming Languages , Stereotaxic Techniques , User-Computer InterfaceABSTRACT
Magnetic resonance imaging is a key diagnostic tool in modern healthcare, yet it can be cost-prohibitive given the high installation, maintenance and operation costs of the machinery. There are approximately seven scanners per million inhabitants and over 90% are concentrated in high-income countries. We describe an ultra-low-field brain MRI scanner that operates using a standard AC power outlet and is low cost to build. Using a permanent 0.055 Tesla Samarium-cobalt magnet and deep learning for cancellation of electromagnetic interference, it requires neither magnetic nor radiofrequency shielding cages. The scanner is compact, mobile, and acoustically quiet during scanning. We implement four standard clinical neuroimaging protocols (T1- and T2-weighted, fluid-attenuated inversion recovery like, and diffusion-weighted imaging) on this system, and demonstrate preliminary feasibility in diagnosing brain tumor and stroke. Such technology has the potential to meet clinical needs at point of care or in low and middle income countries.
Subject(s)
Magnetic Resonance Imaging/instrumentation , Neuroimaging/instrumentation , Adult , Brain Neoplasms/diagnostic imaging , Deep Learning , Diffusion Magnetic Resonance Imaging , Equipment Design , Feasibility Studies , Humans , Magnetic Fields , Magnetic Resonance Imaging/economics , Magnets , Neuroimaging/economics , Phantoms, Imaging , Point-of-Care Systems , Stroke/diagnostic imagingABSTRACT
The chemical synapse is one type of cell-adhesion system that transmits information from a neuron to another neuron in the complex neuronal network in the brain. Synaptic transmission is the rate-limiting step during the information processing in the neuronal network and its plasticity is involved in cognitive functions. Thus, morphological and electrophysiological analyses of synapses are of particular importance in neuroscience research. In the current study, we applied super-resolved three-dimensional stimulated emission depletion (3D-STED) microscopy for the morphological analyses of synapses. This approach allowed us to estimate the precise number of excitatory and inhibitory synapses in the mouse hippocampal tissue. We discovered a region-specific increase in excitatory synapses in a model mouse of autism spectrum disorder, Neuroligin-3 KO, with this method. This type of analysis will open a new field in developmental neuroscience in the future.
Subject(s)
Autism Spectrum Disorder/genetics , CA1 Region, Hippocampal/metabolism , Cell Adhesion Molecules, Neuronal/genetics , Membrane Proteins/genetics , Microscopy/methods , Nerve Tissue Proteins/genetics , Neurons/metabolism , Synapses/genetics , Animals , Autism Spectrum Disorder/diagnostic imaging , Autism Spectrum Disorder/metabolism , Autism Spectrum Disorder/pathology , CA1 Region, Hippocampal/diagnostic imaging , CA1 Region, Hippocampal/pathology , Cell Adhesion Molecules, Neuronal/deficiency , Cognition/physiology , Disease Models, Animal , Gene Knockout Techniques , Homer Scaffolding Proteins/genetics , Homer Scaffolding Proteins/metabolism , Male , Membrane Proteins/deficiency , Membrane Proteins/metabolism , Mice , Mice, Inbred C57BL , Mice, Knockout , Microscopy/instrumentation , Nerve Tissue Proteins/deficiency , Neuroimaging/instrumentation , Neuroimaging/methods , Neurons/pathology , Synapses/metabolism , Synapses/ultrastructure , Synaptic Transmission/physiologyABSTRACT
Microglia are brain-resident immune cells with a repertoire of functions in the brain. However, the extent of their interactions with the vasculature and potential regulation of vascular physiology has been insufficiently explored. Here, we document interactions between ramified CX3CR1 + myeloid cell somata and brain capillaries. We confirm that these cells are bona fide microglia by molecular, morphological and ultrastructural approaches. Then, we give a detailed spatio-temporal characterization of these capillary-associated microglia (CAMs) comparing them with parenchymal microglia (PCMs) in their morphological activities including during microglial depletion and repopulation. Molecularly, we identify P2RY12 receptors as a regulator of CAM interactions under the control of released purines from pannexin 1 (PANX1) channels. Furthermore, microglial elimination triggered capillary dilation, blood flow increase, and impaired vasodilation that were recapitulated in P2RY12-/- and PANX1-/- mice suggesting purines released through PANX1 channels play important roles in activating microglial P2RY12 receptors to regulate neurovascular structure and function.
Subject(s)
Brain/blood supply , Connexins/genetics , Microglia/metabolism , Myeloid Cells/metabolism , Nerve Tissue Proteins/genetics , Receptors, Purinergic P2Y12/genetics , Animals , Brain/cytology , Brain/diagnostic imaging , Brain/metabolism , CX3C Chemokine Receptor 1/genetics , CX3C Chemokine Receptor 1/metabolism , Cell Count , Cerebrovascular Circulation/physiology , Connexins/deficiency , Electrodes, Implanted , Female , Gene Expression Regulation , Genes, Reporter , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolism , Male , Mice , Mice, Knockout , Microglia/cytology , Myeloid Cells/cytology , Nerve Tissue Proteins/deficiency , Neuroimaging/instrumentation , Neuroimaging/methods , Receptors, Purinergic P2Y12/deficiency , Receptors, Purinergic P2Y12/metabolism , Vasodilation/physiologyABSTRACT
In the last decades, non-invasive and portable neuroimaging techniques, such as functional near infrared spectroscopy (fNIRS), have allowed researchers to study the mechanisms underlying the functional cognitive development of the human brain, thus furthering the potential of Developmental Cognitive Neuroscience (DCN). However, the traditional paradigms used for the analysis of infant fNIRS data are still quite limited. Here, we introduce a multivariate pattern analysis for fNIRS data, xMVPA, that is powered by eXplainable Artificial Intelligence (XAI). The proposed approach is exemplified in a study that investigates visual and auditory processing in six-month-old infants. xMVPA not only identified patterns of cortical interactions, which confirmed the existent literature; in the form of conceptual linguistic representations, it also provided evidence for brain networks engaged in the processing of visual and auditory stimuli that were previously overlooked by other methods, while demonstrating similar statistical performance.
Subject(s)
Artificial Intelligence , Cognitive Neuroscience/methods , Growth , Neuroimaging/instrumentation , Spectroscopy, Near-Infrared/statistics & numerical data , Cognitive Neuroscience/instrumentation , Humans , InfantABSTRACT
Radiological examination of the brain is a critical determinant of stroke care pathways. Accessible neuroimaging is essential to detect the presence of intracerebral hemorrhage (ICH). Conventional magnetic resonance imaging (MRI) operates at high magnetic field strength (1.5-3 T), which requires an access-controlled environment, rendering MRI often inaccessible. We demonstrate the use of a low-field MRI (0.064 T) for ICH evaluation. Patients were imaged using conventional neuroimaging (non-contrast computerized tomography (CT) or 1.5/3 T MRI) and portable MRI (pMRI) at Yale New Haven Hospital from July 2018 to November 2020. Two board-certified neuroradiologists evaluated a total of 144 pMRI examinations (56 ICH, 48 acute ischemic stroke, 40 healthy controls) and one ICH imaging core lab researcher reviewed the cases of disagreement. Raters correctly detected ICH in 45 of 56 cases (80.4% sensitivity, 95%CI: [0.68-0.90]). Blood-negative cases were correctly identified in 85 of 88 cases (96.6% specificity, 95%CI: [0.90-0.99]). Manually segmented hematoma volumes and ABC/2 estimated volumes on pMRI correlate with conventional imaging volumes (ICC = 0.955, p = 1.69e-30 and ICC = 0.875, p = 1.66e-8, respectively). Hematoma volumes measured on pMRI correlate with NIH stroke scale (NIHSS) and clinical outcome (mRS) at discharge for manual and ABC/2 volumes. Low-field pMRI may be useful in bringing advanced MRI technology to resource-limited settings.
Subject(s)
Cerebral Hemorrhage/diagnostic imaging , Magnetic Resonance Imaging/methods , Adult , Aged , Aged, 80 and over , Brain/diagnostic imaging , Female , Humans , Magnetic Resonance Imaging/economics , Magnetic Resonance Imaging/instrumentation , Male , Middle Aged , Neuroimaging/economics , Neuroimaging/instrumentation , Neuroimaging/methodsABSTRACT
Multisite magnetic resonance imaging (MRI) is increasingly used in clinical research and development. Measurement biases-caused by site differences in scanner/image-acquisition protocols-negatively influence the reliability and reproducibility of image-analysis methods. Harmonization can reduce bias and improve the reproducibility of multisite datasets. Herein, a traveling-subject (TS) dataset including 56 T1-weighted MRI scans of 20 healthy participants in three different MRI procedures-20, 19, and 17 subjects in Procedures 1, 2, and 3, respectively-was considered to compare the reproducibility of TS-GLM, ComBat, and TS-ComBat harmonization methods. The minimum participant count required for harmonization was determined, and the Cohen's d between different MRI procedures was evaluated as a measurement-bias indicator. The measurement-bias reduction realized with different methods was evaluated by comparing test-retest scans for 20 healthy participants. Moreover, the minimum subject count for harmonization was determined by comparing test-retest datasets. The results revealed that TS-GLM and TS-ComBat reduced measurement bias by up to 85 and 81.3%, respectively. Meanwhile, ComBat showed a reduction of only 59.0%. At least 6 TSs were required to harmonize data obtained from different MRI scanners, complying with the imaging protocol predetermined for multisite investigations and operated with similar scan parameters. The results indicate that TS-based harmonization outperforms ComBat for measurement-bias reduction and is optimal for MRI data in well-prepared multisite investigations. One drawback is the small sample size used, potentially limiting the applicability of ComBat. Investigation on the number of subjects needed for a large-scale study is an interesting future problem.
Subject(s)
Brain/anatomy & histology , Brain/diagnostic imaging , Image Processing, Computer-Assisted/methods , Magnetic Resonance Imaging , Multicenter Studies as Topic , Neuroimaging , Adult , Humans , Image Processing, Computer-Assisted/instrumentation , Image Processing, Computer-Assisted/standards , Magnetic Resonance Imaging/instrumentation , Magnetic Resonance Imaging/methods , Magnetic Resonance Imaging/standards , Multicenter Studies as Topic/instrumentation , Multicenter Studies as Topic/methods , Multicenter Studies as Topic/standards , Neuroimaging/instrumentation , Neuroimaging/methods , Neuroimaging/standardsABSTRACT
There is an increasing interest in quantitative imaging of T1, T2 and diffusion contrast in the brain due to greater robustness against bias fields and artifacts, as well as better biophysical interpretability in terms of microstructure. However, acquisition time constraints are a challenge, particularly when multiple quantitative contrasts are desired and when extensive sampling of diffusion directions, high b-values or long diffusion times are needed for multi-compartment microstructure modeling. Although ultra-high fields of 7 T and above have desirable properties for many MR modalities, the shortening T2 and the high specific absorption rate (SAR) of inversion and refocusing pulses bring great challenges to quantitative T1, T2 and diffusion imaging. Here, we present the MESMERISED sequence (Multiplexed Echo Shifted Multiband Excited and Recalled Imaging of STEAM Encoded Diffusion). MESMERISED removes the dead time in Stimulated Echo Acquisition Mode (STEAM) imaging by an echo-shifting mechanism. The echo-shift (ES) factor is independent of multiband (MB) acceleration and allows for very high multiplicative (ESxMB) acceleration factors, particularly under moderate and long mixing times. This results in super-acceleration and high time efficiency at 7 T for quantitative T1 and diffusion imaging, while also retaining the capacity to perform quantitative T2 and B1 mapping. We demonstrate the super-acceleration of MESMERISED for whole-brain T1 relaxometry with total acceleration factors up to 36 at 1.8 mm isotropic resolution, and up to 54 at 1.25 mm resolution qT1 imaging, corresponding to a 6x and 9x speedup, respectively, compared to MB-only accelerated acquisitions. We then demonstrate highly efficient diffusion MRI with high b-values and long diffusion times in two separate cases. First, we show that super-accelerated multi-shell diffusion acquisitions with 370 whole-brain diffusion volumes over 8 b-value shells up to b = 7000 s/mm2 can be generated at 2 mm isotropic in under 8 minutes, a data rate of almost a volume per second, or at 1.8 mm isotropic in under 11 minutes, achieving up to 3.4x speedup compared to MB-only. A comparison of b = 7000 s/mm2 MESMERISED against standard MB pulsed gradient spin echo (PGSE) diffusion imaging shows 70% higher SNR efficiency and greater effectiveness in supporting complex diffusion signal modeling. Second, we demonstrate time-efficient sampling of different diffusion times with 1.8 mm isotropic diffusion data acquired at four diffusion times up to 290 ms, which supports both Diffusion Tensor Imaging (DTI) and Diffusion Kurtosis Imaging (DKI) at each diffusion time. Finally, we demonstrate how adding quantitative T2 and B1+ mapping to super-accelerated qT1 and diffusion imaging enables efficient quantitative multi-contrast mapping with the same MESMERISED sequence and the same readout train. MESMERISED extends possibilities to efficiently probe T1, T2 and diffusion contrast for multi-component modeling of tissue microstructure.
Subject(s)
Brain/diagnostic imaging , Diffusion Magnetic Resonance Imaging/methods , Echo-Planar Imaging/methods , Neuroimaging/methods , Brain Mapping/instrumentation , Brain Mapping/methods , Diffusion Magnetic Resonance Imaging/instrumentation , Echo-Planar Imaging/instrumentation , Humans , Image Processing, Computer-Assisted , Models, Theoretical , Neuroimaging/instrumentationABSTRACT
T2 quantification is commonly attempted by applying an exponential fit to proton density (PD) and transverse relaxation (T2)-weighted fast spin echo (FSE) images. However, inter-site studies have noted systematic differences between vendors in T2 maps computed via standard exponential fitting due to imperfect slice refocusing, different refocusing angles and transmit field (B1+) inhomogeneity. We examine T2 mapping at 3T across 13 sites and two vendors in healthy volunteers from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database using both a standard exponential and a Bloch modelling approach. The standard exponential approach resulted in highly variable T2 values across different sites and vendors. The two-echo fitting method based on Bloch equation modelling of the pulse sequence with prior knowledge of the nominal refocusing angles, slice profiles, and estimated B1+ maps yielded similar T2 values across sites and vendors by accounting for the effects of indirect and stimulated echoes. By modelling the actual refocusing angles used, T2 quantification from PD and T2-weighted images can be applied in studies across multiple sites and vendors.
Subject(s)
Gray Matter/diagnostic imaging , Magnetic Resonance Imaging , Neuroimaging , White Matter/diagnostic imaging , Aged , Aged, 80 and over , Female , Humans , Magnetic Resonance Imaging/instrumentation , Magnetic Resonance Imaging/methods , Magnetic Resonance Imaging/standards , Male , Middle Aged , Models, Theoretical , Neuroimaging/instrumentation , Neuroimaging/methods , Neuroimaging/standards , Retrospective StudiesABSTRACT
Multi-scanner MRI studies are reliant on understanding the apparent differences in imaging measures between different scanners. We provide a comprehensive analysis of T1 -weighted and diffusion MRI (dMRI) structural brain measures between a 1.5 T GE Signa Horizon HDx and a 3 T Siemens Magnetom Prisma using 91 community-dwelling older participants (aged 82 years). Although we found considerable differences in absolute measurements (global tissue volumes were measured as ~6-11% higher and fractional anisotropy [FA] was 33% higher at 3 T than at 1.5 T), between-scanner consistency was good to excellent for global volumetric and dMRI measures (intraclass correlation coefficient [ICC] range: .612-.993) and fair to good for 68 cortical regions (FreeSurfer) and cortical surface measures (mean ICC: .504-.763). Between-scanner consistency was fair for dMRI measures of 12 major white matter tracts (mean ICC: .475-.564), and the general factors of these tracts provided excellent consistency (ICC ≥ .769). Whole-brain structural networks provided good to excellent consistency for global metrics (ICC ≥ .612). Although consistency was poor for individual network connections (mean ICCs: .275-.280), this was driven by a large difference in network sparsity (.599 vs. .334), and consistency was improved when comparing only the connections present in every participant (mean ICCs: .533-.647). Regression-based k-fold cross-validation showed that, particularly for global volumes, between-scanner differences could be largely eliminated (R2 range .615-.991). We conclude that low granularity measures of brain structure can be reliably matched between the scanners tested, but caution is warranted when combining high granularity information from different scanners.
Subject(s)
Brain/anatomy & histology , Brain/diagnostic imaging , Magnetic Resonance Imaging , Neuroimaging , Aged, 80 and over , Birth Cohort , Cohort Studies , Female , Humans , Magnetic Resonance Imaging/instrumentation , Magnetic Resonance Imaging/standards , Male , Neuroimaging/instrumentation , Neuroimaging/standards , ScotlandABSTRACT
Motor actions in fMRI settings require specialized hardware to monitor, record, and control the subjects behavior. Commercially available options for such behavior tracking or control are very restricted and costly. We present a novel grasp manipulandum in a modular design, consisting of MRI-compatible, 3D printable buttons and a chassis for mounting. Button presses are detected by the interruption of an optical fiber path, which is digitized by a photodiode and subsequent signal amplification and thresholding. Two feedback devices (manipulanda) are constructed, one for macaques (Macaca mulatta) and one for human use. Both devices have been tested in their specific experimental setting and possible improvements are reported. Design files are shared under an open hardware license.
Subject(s)
Magnetic Resonance Imaging/instrumentation , Neuroimaging/instrumentation , Printing, Three-Dimensional , Animals , Equipment Design , Hand Strength , Humans , Macaca , Magnetic Resonance Imaging/economics , Neuroimaging/economics , Phantoms, Imaging , SoftwareABSTRACT
New technologies are key to understanding the dynamic activity of neural circuits and systems in the brain. Here, we show that a minimally invasive approach based on ultrasound can be used to detect the neural correlates of movement planning, including directions and effectors. While non-human primates (NHPs) performed memory-guided movements, we used functional ultrasound (fUS) neuroimaging to record changes in cerebral blood volume with 100 µm resolution. We recorded from outside the dura above the posterior parietal cortex, a brain area important for spatial perception, multisensory integration, and movement planning. We then used fUS signals from the delay period before movement to decode the animals' intended direction and effector. Single-trial decoding is a prerequisite to brain-machine interfaces, a key application that could benefit from this technology. These results are a critical step in the development of neuro-recording and brain interface tools that are less invasive, high resolution, and scalable.
Subject(s)
Intention , Neuroimaging/methods , Parietal Lobe/physiology , Psychomotor Performance/physiology , Ultrasonography/methods , Animals , Brain Mapping/methods , Brain-Computer Interfaces , Macaca mulatta , Male , Movement , Neuroimaging/instrumentation , Ultrasonography/instrumentationABSTRACT
PURPOSE: To share our experiences in implementing a dedicated magnetic resonance (MR) scanner for radiotherapy (RT) treatment planning using a novel coil setup for brain imaging in treatment position as well as to present developed core protocols with sequences specifically tuned for brain and prostate RT treatment planning. MATERIALS AND METHODS: Our novel setup consists of two large 18-channel flexible coils and a specifically designed wooden mask holder mounted on a flat tabletop overlay, which allows patients to be measured in treatment position with mask immobilization. The signal-to-noise ratio (SNR) of this setup was compared to the vendor-provided flexible coil RT setup and the standard setup for diagnostic radiology. The occurrence of motion artifacts was quantified. To develop magnetic resonance imaging (MRI) protocols, we formulated site- and disease-specific clinical objectives. RESULTS: Our novel setup showed mean SNR of 163⯱ 28 anteriorly, 104⯱ 23 centrally, and 78⯱ 14 posteriorly compared to 84⯱ 8 and 102⯱ 22 anteriorly, 68⯱ 6 and 95⯱ 20 centrally, and 56⯱ 7 and 119⯱ 23 posteriorly for the vendor-provided and diagnostic setup, respectively. All differences were significant (pâ¯> 0.05). Image quality of our novel setup was judged suitable for contouring by expert-based assessment. Motion artifacts were found in 8/60 patients in the diagnostic setup, whereas none were found for patients in the RT setup. Site-specific core protocols were designed to minimize distortions while optimizing tissue contrast and 3D resolution according to indication-specific objectives. CONCLUSION: We present a novel setup for high-quality imaging in treatment position that allows use of several immobilization systems enabling MR-only workflows, which could reduce unnecessary dose and registration inaccuracies.
Subject(s)
Brain Neoplasms/radiotherapy , Brain/diagnostic imaging , Magnetic Resonance Imaging/methods , Radiotherapy, Image-Guided/methods , Brain/radiation effects , Brain Neoplasms/diagnostic imaging , Equipment Design , Humans , Magnetic Resonance Imaging/instrumentation , Neuroimaging/instrumentation , Neuroimaging/methods , Patient Positioning , Radiotherapy Planning, Computer-Assisted/instrumentation , Radiotherapy Planning, Computer-Assisted/methods , Radiotherapy, Image-Guided/instrumentationABSTRACT
BACKGROUND: Here we report the application of optical frequency domain imaging (OFDI), a new optical coherence tomography device, for intravascular visualization in the treatment of a recanalized unruptured internal carotid artery aneurysm that was treated initially by stent-assisted coil embolization. CASE DESCRIPTION: OFDI revealed malapposition of the stent and lack of neointimal growth at the aneurysm neck, which was treated by deployment of a Pipeline Embolization Device to overlap the stent. An angiogram performed 1 year after the procedure revealed perfect healing of the aneurysm, and OFDI clearly demonstrated good stent apposition and total endothelialization over the aneurysm neck. CONCLUSIONS: OFDI/OCT appears to be a useful diagnostic tool for evaluating stent-strut apposition over the vessel wall and the grade of neointimal endothelialization across the neck of the aneurysm in aneurysmal recanalization.
Subject(s)
Carotid Artery, Internal/diagnostic imaging , Intracranial Aneurysm/diagnostic imaging , Intracranial Aneurysm/therapy , Neuroimaging/methods , Tomography, Optical Coherence/methods , Carotid Artery Diseases/diagnostic imaging , Carotid Artery Diseases/therapy , Embolization, Therapeutic/methods , Endovascular Procedures/methods , Female , Humans , Middle Aged , Neuroimaging/instrumentation , Stents , Tomography, Optical Coherence/instrumentationABSTRACT
While NMR and MRI are often thought of as expensive techniques requiring large institutional investment, opportunities for low-cost, low-field NMR and MRI abound. We discuss a number of approaches to performing magnetic resonance experiments with inexpensive, easy to find or build components, aimed at applications in industry, education, and research. Opportunities that aim to make NMR accessible to a broad community are highlighted. We describe and demonstrate some projects from our laboratory, including a new prototype instrument for measurements at frequencies up to â¼200â¯kHz and demonstrate its application to the study of the rapidly advancing technique known as inhomogeneous magnetization transfer imaging, a promising method for characterizing myelin in vivo.
Subject(s)
Magnetic Resonance Imaging/economics , Magnetic Resonance Imaging/instrumentation , Magnetic Resonance Spectroscopy/economics , Magnetic Resonance Spectroscopy/instrumentation , Neuroimaging/instrumentation , Equipment Design , Humans , SoftwareABSTRACT
Cerebral stroke greatly contributes to death and disability rates in China and the whole world. Effective non-invasive imaging device for bedside monitoring of stroke is critically needed in clinically. This study developed a lightweight (350 kg) and low-footprint magnetic resonance imaging (MRI) system for brain imaging. Static magnetic field was built using an H-typed permanent magnet, which has 50.9 mT magnetic field strength (corresponding to 2.167 MHz proton Larmor frequency). Biplanar gradient coils were designed using the target field method based on dipole equivalent. Radio-frequency coils were optimized by particle swarm optimization. The 2 MHz MRI system was deployed in the Department of Neurology of hospital to test its performance in stroke imaging detection. Gradient recall echo and fast spin echo sequences were utilized to acquire T1- and T2-weighted MR images, respectively. Brain images of a healthy volunteer, a patient with hemorrhagic stroke, a patient of ischemic stroke, and a patient with ischemic stroke and images from 17-day long-term monitoring of hemorrhagic stroke were obtained with a 1.5 mm * 2.0 mm spatial resolution in plane, and a 10 mm thickness.
Subject(s)
Magnetic Resonance Imaging/instrumentation , Neuroimaging/instrumentation , Point-of-Care Testing , Stroke/diagnostic imaging , Adult , China , Equipment Design , Humans , Image Enhancement , Male , Middle Aged , Phantoms, ImagingABSTRACT
No disponible
Subject(s)
Humans , Male , Female , Adolescent , Young Adult , Adult , Middle Aged , Aged , Thinking , Schizophrenia/diagnosis , Schizophrenia/therapy , Cognition Disorders/physiopathology , Frontal Lobe/physiopathology , Language Disorders/etiology , Cerebrum/physiopathology , Language Disorders/pathology , Cerebrum/diagnostic imaging , Neuroimaging/instrumentationABSTRACT
Patients in the intensive care unit require fast and efficient handling, including in-diagnosis service. The objectives of this study are to produce a computer-aided system so that it can help radiologists to classify the types of brain tumors suffered by patients quickly and accurately; to build applications that can determine the location of brain tumors from CT scan images; and to get the results of the analysis of the system design. The combination of the zoning algorithm with Learning Vector Quantization can increase the speed of computing and can classify normal and abnormal brains with an average accuracy of 85%.