Visualizing brain inflammation with a shingled-leg radio-frequency head probe for 19F/1H MRI.
Ontology highlight
ABSTRACT:
SUBMITTER: Waiczies H
PROVIDER: S-EPMC3573344 | biostudies-literature | 2013
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:UnlabelledBackgroundNon-invasive imaging of inflammation to measure the progression of autoimmune diseases, such as rheumatoid arthritis (RA), and to monitor responses to therapy is critically needed. V-Sense, a perfluorocarbon (PFC) contrast agent that preferentially labels inflammatory cells, which are then recruited out of systemic circulation to sites of inflammation, enables detection by 19F MRI. With no 19F background in the host, detection is highly-specific and can act as a proxy biomarker of the degree of inflammation present.MethodsCollagen-induced arthritis in rats, a model with many similarities to human RA, was used to study the ability of the PFC contrast agent to reveal the accumulation of inflammation over time using 19F MRI. Disease progression in the rat hind limbs was monitored by caliper measurements and 19F MRI on days 15, 22 and 29, including the height of clinically symptomatic disease. Naïve rats served as controls. The capacity of the PFC contrast agent and 19F MRI to assess the effectiveness of therapy was studied in a cohort of rats administered oral prednisolone on days 14 to 28.ResultsQuantification of 19F signal measured by MRI in affected limbs was linearly correlated with disease severity. In animals with progressive disease, increases in 19F signal reflected the ongoing recruitment of inflammatory cells to the site, while no increase in 19F signal was observed in animals receiving treatment which resulted in clinical resolution of disease.ConclusionThese results indicate that 19F MRI may be used to quantitatively and qualitatively evaluate longitudinal responses to a therapeutic regimen, while additionally revealing the recruitment of monocytic cells involved in the inflammatory process to the anatomical site. This study may support the use of 19F MRI to clinically quantify and monitor the severity of inflammation, and to assess the effectiveness of treatments in RA and other diseases with an inflammatory component.
| S-EPMC3506445 | biostudies-literature
Project description:Emulsified perfluorocarbons (PFCs) are preferentially phagocytized by monocytes/macrophages and are readily detected by (19)F MRI. This study tests the hypothesis that (19)F MRI can be used to quantitate pulmonary inflammation by tracking of infiltrating PFC-loaded monocytes.Pneumonia was induced in mice by intratracheal instillation of lipopolysaccharides (LPS) followed by intravenous injection of PFCs. Whereas regular (1)H MRI provided no evidence of lung injury 24 hours after LPS, the concurrent (19)F images clearly show PFC accumulation in both pulmonary lobes. Imaging at 48 hours after LPS revealed signals in (1)H images at the same location as the 24-hour (19)F signals. Thus, progressive pneumonia was first predicted by (19)F MRI early after PFC administration. Without LPS, at no time were (19)F signals observed within the lung. Histology and fluorescence-activated cell sorting (FACS) combined with (19)F MRI confirmed the presence of infiltrating PFC-loaded monocytes/macrophages after LPS challenge. Additional experiments with graded doses of LPS demonstrated that (19)F signal intensity strongly correlated with both LPS dose and pathological markers of lung inflammation. In separate studies, dexamethasone and CGS21680 (adenosine 2A receptor agonist) were used to demonstrate the ability of (19)F MRI to monitor anti-inflammatory therapies.PFCs serve as a contrast agent for the prognostic and quantitative assessment of pulmonary inflammation by in vivo (19)F MRI, which is characterized by a high degree of specificity due to the lack of any (19)F background. Because PFCs are biochemically inert, this approach may also be suitable for human applications.
| S-EPMC3138443 | biostudies-literature
Project description:High-field (≥ 3T) MRI provides a means to increase the signal-to-noise ratio, due to its higher tissue magnetization compared with 1.5T. However, both the static magnetic field (B(0)) and the transmit radio-frequency (RF) field (B 1+) inhomogeneities are comparatively higher at higher field strengths than those at 1.5T. These challenging factors at high-field strengths make it more difficult to accurately calibrate the transmit RF gain using standard RF calibration procedures. An image-based RF calibration procedure was therefore developed, in order to accurately calibrate the transmit RF gain within a specific region-of-interest (ROI). Using a turbo fast low-angle shot (TurboFLASH) pulse sequence with centric k-space reordering, a series of 'saturation-no-recovery' images was acquired by varying the flip angle of the preconditioning pulse. In the resulting images, the signal null occurs in regions where the flip angle of the preconditioning pulse is 90°. For a given ROI, the mean signal can be plotted as a function of the nominal flip angle, and the resulting curve can be used to quantitatively identify the signal null. This image-guided RF calibration procedure was evaluated through phantom and volunteer imaging experiments at 3T and 7T. The image-guided RF calibration results in vitro were consistent with standard B(0) and B 1+ maps. The standard automated RF calibration procedure produced approximately 20% and 15-30% relative error in the transmit RF gain in the left kidney at 3T and brain at 7T, respectively. For initial application, a T(2) mapping pulse sequence was applied at 7T. The T(2) measurements in the thalamus at 7T were 60.6 ms and 48.2 ms using the standard and image-guided RF calibration procedures, respectively. This rapid, image-guided RF calibration procedure can be used to optimally calibrate the flip angle for a given ROI and thus minimize measurement errors for quantitative MRI and MR spectroscopy.
| S-EPMC2988285 | biostudies-other
Project description:BackgroundOncolytic virotherapy of tumors is an up-coming, promising therapeutic modality of cancer therapy. Unfortunately, non-invasive techniques to evaluate the inflammatory host response to treatment are rare. Here, we evaluate (19)F magnetic resonance imaging (MRI) which enables the non-invasive visualization of inflammatory processes in pathological conditions by the use of perfluorocarbon nanoemulsions (PFC) for monitoring of oncolytic virotherapy.Methodology/principal findingsThe Vaccinia virus strain GLV-1h68 was used as an oncolytic agent for the treatment of different tumor models. Systemic application of PFC emulsions followed by (1)H/(19)F MRI of mock-infected and GLV-1h68-infected tumor-bearing mice revealed a significant accumulation of the (19)F signal in the tumor rim of virus-treated mice. Histological examination of tumors confirmed a similar spatial distribution of the (19)F signal hot spots and CD68(+)-macrophages. Thereby, the CD68(+)-macrophages encapsulate the GFP-positive viral infection foci. In multiple tumor models, we specifically visualized early inflammatory cell recruitment in Vaccinia virus colonized tumors. Furthermore, we documented that the (19)F signal correlated with the extent of viral spreading within tumors.Conclusions/significanceThese results suggest (19)F MRI as a non-invasive methodology to document the tumor-associated host immune response as well as the extent of intratumoral viral replication. Thus, (19)F MRI represents a new platform to non-invasively investigate the role of the host immune response for therapeutic outcome of oncolytic virotherapy and individual patient response.
| S-EPMC3575337 | biostudies-literature
Project description:BackgroundOne-third of intractable epilepsy patients have no visually identifiable focus for neurosurgery based on imaging tests [magnetic resonance imaging (MRI)-negative cases]. Stereo-electroencephalography-guided radio-frequency thermocoagulation (SEEG-guided RF-TC) is utilized in the clinical treatment of epilepsy to lower the incidence of complications post-open surgery.ObjectiveThis study aimed to identify prognostic factors and long-term seizure outcomes in SEEG-guided RF-TC for patients with MRI-negative epilepsy.DesignThis was a single-center retrospective cohort study.MethodsWe included 30 patients who had undergone SEEG-guided RF-TC at Sanbo Brain Hospital, Capital Medical University, from April 2015 to December 2019. The probability of remaining seizure-free and the plotted survival curves were analyzed. Prognostic factors were analyzed using log-rank tests in univariate analysis and the Cox regression model in multivariate analysis.ResultsWith a mean time of 31.07 ± 2.64 months (median 30.00, interquartile range: 18.00-40.00 months), 11 out of 30 patients (36.7%) were classified as International League Against Epilepsy class 1 in the last follow-up. The mean time of remaining seizure-free was 21.33 ± 4.55 months [95% confidence interval (CI) 12.41-30.25], and the median time was 3.00 ± 0.54 months (95% CI 1.94-4.06). Despite falling in the initial year, the probability of remaining seizure-free gradually stabilizes in the subsequent years. The patients were more likely to obtain seizure freedom when the epileptogenic zone was located in the insular lobe or with one focus on the limbic system (p = 0.034, hazard ratio 5.019, 95% CI 1.125-22.387).ConclusionOur findings may be applied to guide individualized surgical interventions and help clinicians make better decisions.
| S-EPMC10943718 | biostudies-literature
Project description:Fluorine-19 (19F) Magnetic Resonance Imaging (MRI) is an emerging modality for molecular imaging and cell tracking. The hydrophobicity of current exogenous probes, perfluorocarbons (PFCs) and perfluoropolyethers (PFPEs), limits the formulation options available for in vivo applications. Hydrophilic probes permit more formulation flexibility. Further, the broad Nuclear Magnetic Resonance (NMR) chemical shift range of organofluorine species enables multiple probes with unique 19F MR signatures for simultaneous interrogation of distinct molecular targets in vivo. We report herein a flexible approach to stable liposomal formulations of hydrophilic fluorinated molecules (each bearing numerous magnetically equivalent 19F atoms), with 19F encapsulation of up to 22.7?mg/mL and a per particle load of 3.6?×?106 19F atoms. Using a combination of such probes, we demonstrate, with no chemical shift artifacts, the simultaneous imaging of multiple targets within a given target volume by spectral 19F MRI.
| S-EPMC5811496 | biostudies-literature
Project description:Increasing amounts of attention are being paid to the study of Soft Sensors and Soft Systems. Soft Robotic Systems require input from advances in the field of Soft Sensors. Soft sensors can help a soft robot to perceive and to act upon its immediate environment. The concept of integrating sensing capabilities into soft robotic systems is becoming increasingly important. One challenge is that most of the existing soft sensors have a requirement to be hardwired to power supplies or external data processing equipment. This requirement hinders the ability of a system designer to integrate soft sensors into soft robotic systems. In this article, we design, fabricate, and characterize a new soft sensor, which benefits from a combination of radio-frequency identification (RFID) tag design and microfluidic sensor fabrication technologies. We designed this sensor using the working principle of an RFID transporter antenna, but one whose resonant frequency changes in response to an applied strain. This new microfluidic sensor is intrinsically stretchable and can be reversibly strained. This sensor is a passive and wireless device, and as such, it does not require a power supply and is capable of transporting data without a wired connection. This strain sensor is best understood as an RFID tag antenna; it shows a resonant frequency change from approximately 860 to 800 MHz upon an applied strain change from 0% to 50%. Within the operating frequency, the sensor shows a standoff reading range of >7.5 m (at the resonant frequency). We characterize, experimentally, the electrical performance and the reliability of the fabrication process. We demonstrate a pneumatic soft robot that has four microfluidic sensors embedded in four of its legs, and we describe the implementation circuit to show that we can obtain movement information from the soft robot using our wireless soft sensors.
| S-EPMC6386780 | biostudies-literature
Project description:Magnetic resonance imaging (MRI) is an important key for non-invasive visualization of immigrating cells in in vivo studies. We use Perflourcarbons (PFC) coupled to green fluorescent protein (GFP) for a 1H and 19F MRI detection. To this end, we engineered synthetic cell surface receptors, “Cargo Internalization Receptors” (CIR), which contain a GFP-nanobody and specifically bind GFP, followed by a rapid internalization of the GFP-PFC particles, but without inducing any signaling in the targeted cells. In order to explore the suitability of different uptake mechanisms we constructed three different CIRs, which contain different cytoplasmic domains that have different internalizations motifs and properties to enable the specific uptake of the GFP-PFC cargo in CIR-transfected cells. We show that the CIR approach is working in vitro, and has the potential to specifically track CIR containing cells by 1H and 19F MRI.
2019-05-27 | GSE106215 | GEO
Project description:Since the days of Hertz, radio transmitters have evolved from rudimentary circuits emitting around 50 MHz to modern ubiquitous Wi-Fi devices operating at gigahertz radio bands. As wireless data traffic continues to increase, there is a need for new communication technologies capable of high-frequency operation for high-speed data transfer. Here, we give a proof of concept of a compact radio frequency transmitter based on a semiconductor laser frequency comb. In this laser, the beating among the coherent modes oscillating inside the cavity generates a radio frequency current, which couples to the electrodes of the device. We show that redesigning the top contact of the laser allows one to exploit the internal oscillatory current to drive a dipole antenna, which radiates into free space. In addition, direct modulation of the laser current permits encoding a signal in the radiated radio frequency carrier. Working in the opposite direction, the antenna can receive an external radio frequency signal, couple it to the active region, and injection lock the laser. These results pave the way for applications and functionality in optical frequency combs, such as wireless radio communication and wireless synchronization to a reference source.
| S-EPMC6511043 | biostudies-literature
Project description:Quantitative modeling of specific absorption rate and temperature rise within the human body during 1.5 T and 3 T MRI scans is of clinical significance to ensure patient safety. This work presents justification, via validation and comparison, of the potential use of the Visible Human Project (VHP) derived Computer Aided Design (CAD) female full body computational human model for non-clinical assessment of female patients of age 50-65 years with a BMI of 30-36 during 1.5 T and 3 T based MRI procedures. The initial segmentation validation and four different application examples have been identified and used to compare to numerical simulation results obtained using VHP Female computational human model under the same or similar conditions. The first application example provides a simulation-to-simulation validation while the latter three application examples compare with measured experimental data. Given the same or similar coil settings, the computational human model generates meaningful results for SAR, B1 field, and temperature rise when used in conjunction with the 1.5 T birdcage MRI coils or at higher frequencies corresponding to 3 T MRI. Notably, the deviation in temperature rise from experiment did not exceed 2.75° C for three different heating scenarios considered in the study with relative deviations of 10%, 25%, and 20%. This study provides a reasonably systematic validation and comparison of the VHP-Female CAD v.3.0-5.0 surface-based computational human model starting with the segmentation validation and following four different application examples.
| S-EPMC8664205 | biostudies-literature