scholarly journals A protein-based biosensor for detecting calcium by magnetic resonance imaging

2021 ◽  
Author(s):  
Harun F. Ozbakir ◽  
Austin D.C. Miller ◽  
Kiara B. Fishman ◽  
André F. Martins ◽  
Tod E. Kippin ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Neural Activity ◽  
Calcium Binding ◽  
Relaxation Times ◽  
Neuronal Cell ◽  
Brain Regions ◽  
Resonance Imaging ◽  
Biologically Relevant

ABSTRACTCalcium-responsive contrast agents for magnetic resonance imaging (MRI) offer an attractive approach to noninvasively image neural activity with wide coverage in deep brain regions. However, current MRI sensors for calcium are based on synthetic architectures fundamentally incompatible with genetic technologies for in vivo delivery and targeting. Here, we present a protein-based MRI sensor for calcium, derived from a calcium-binding protein known as calprotectin. Calcium-binding causes calprotectin to sequester manganese. We demonstrate that this mechanism allows calprotectin to alter T1 and T2 weighted contrast in response to biologically relevant calcium concentrations. Corresponding changes in relaxation times are comparable to synthetic calcium sensors and exceed those of previous protein-based MRI sensors for other neurochemical targets. The biological applicability of calprotectin was established by detecting calcium in lysates prepared from a neuronal cell line. Calprotectin thus represents a promising path towards imaging neural activity by combining the benefits of MRI and protein sensors.

scholarly journals An update on magnetic resonance imaging markers in AD

2020 ◽  
Vol 13 ◽  
pp. 175628642094798
Author(s):  
Michela Leocadi ◽  
Elisa Canu ◽  
Davide Calderaro ◽  
Davide Corbetta ◽  
Massimo Filippi ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Scientific Literature ◽  
A Priori ◽  
Deep Understanding ◽  
Brain Regions ◽  
Diagnostic Process ◽  
Resonance Imaging ◽  
Brain Structure And Function

The purpose of the present review is to provide an update of the available recent scientific literature on the use of magnetic resonance imaging (MRI) in Alzheimer’s disease (AD). MRI is playing an increasingly important role in the characterization of the AD signatures, which can be useful in both the diagnostic process and monitoring of disease progression. Furthermore, this technique is unique in assessing brain structure and function and provides a deep understanding of in vivo evolution of cerebral pathology. In the reviewing process, we established a priori criteria and we thoroughly searched the very recent scientific literature (January 2018–March 2020) for relevant articles on this topic. In summary, we selected 73 articles out of 1654 publications retrieved from PubMed. Based on this selection, this review summarizes the recent application of MRI in clinical trials, defining the predementia stages of AD, the clinical utility of MRI, proposal of novel biomarkers and brain regions of interest, and assessing the relationship between MRI and cognitive features, risk and protective factors of AD. Finally, the value of a multiparametric approach in clinical and preclinical stages of AD is discussed.

scholarly journals Image-guided neural activity manipulation with a paramagnetic drug

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Sarah Bricault ◽  
Ali Barandov ◽  
Peter Harvey ◽  
Elizabeth DeTienne ◽  
Aviad Hai ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Neural Activity ◽  
Brain Activity ◽  
Pharmacological Properties ◽  
Resonance Imaging ◽  
Significant Challenge ◽  
Image Guided

AbstractTargeted manipulations of neural activity are essential approaches in neuroscience and neurology, but monitoring such procedures in the living brain remains a significant challenge. Here we introduce a paramagnetic analog of the drug muscimol that enables targeted neural inactivation to be performed with feedback from magnetic resonance imaging. We validate pharmacological properties of the compound in vitro, and show that its distribution in vivo reliably predicts perturbations to brain activity.

scholarly journals From signal-based to comprehensive magnetic resonance imaging

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gyula Kotek ◽  
Laura Nunez-Gonzalez ◽  
Mika W. Vogel ◽  
Gabriel P. Krestin ◽  
Dirk H. J. Poot ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
Homogeneous Magnetic Field ◽  
Proton Density ◽  
Resonance Imaging ◽  
Experimental Conditions ◽  
Magnetic Resonance Parameters ◽  
Magnetic Resonance Imaging Mri

AbstractWe present and evaluate a new insight into magnetic resonance imaging (MRI). It is based on the algebraic description of the magnetization during the transient response—including intrinsic magnetic resonance parameters such as longitudinal and transverse relaxation times (T1, T2) and proton density (PD) and experimental conditions such as radiofrequency field (B1) and constant/homogeneous magnetic field (B0) from associated scanners. We exploit the correspondence among three different elements: the signal evolution as a result of a repetitive sequence of blocks of radiofrequency excitation pulses and encoding gradients, the continuous Bloch equations and the mathematical description of a sequence as a linear system. This approach simultaneously provides, in a single measurement, all quantitative parameters of interest as well as associated system imperfections. Finally, we demonstrate the in-vivo applicability of the new concept on a clinical MRI scanner.

Assessment of T2 Relaxation Times for Normal Canine Knee Articular Cartilage by T2 Mapping Using 1.5-T Magnetic Resonance Imaging

2017 ◽  
Vol 30 (06) ◽  
pp. 391-397 ◽  
Author(s):  
Asami Matsui ◽  
Miki Shimizu ◽  
Brian Beale ◽  
Fumitaka Takahashi ◽  
Sinya Yamaguchi
Keyword(s):  
Magnetic Resonance Imaging ◽  
Articular Cartilage ◽  
Magnetic Resonance ◽  
T2 Mapping ◽  
Relaxation Times ◽  
Cartilage Thickness ◽  
Resonance Imaging ◽  
T2 Relaxation ◽  
Stifle Joint

Abstract Objectives This study aims to assess and compare the T2 relaxation times for articular cartilage of normal canine stifle joints in four regions by T2 mapping using a 1.5-T magnetic resonance imaging (MRI). Methods In vivo prospective study: 20 hindlimbs (left and right) from 10 normal healthy beagle dogs (n = 20). The region of interest (ROI) was subdivided into medial and lateral condyles of femoral cartilage (MF and LF, respectively) and medial and lateral condyles of tibial cartilage (MT and LT, respectively). The T2 relaxation times were assessed in regions where the cartilage thickness was greater than 0.5 mm. Results The median maximum cartilage thickness (mm) of the four ROI were 0.7 (range: 0.9–0.6), 0.6 (range: 0.7–0.5), 0.7 (range: 0.9–0.5) and 0.6 (range: 0.8–0.5) at MF, LF, MT and LT, respectively. The errors in the measurement (%) of the four ROI were 64.3 (range: 50.0–75.0), 75.0 (range: 64.3–90.0), 64.3 (range: 20.0–90.0) and 75.0 (range: 56.3–90.0) at MF, LF, MT and LT, respectively. The median T2 relaxation times (ms) for the articular cartilage of the four ROI were 70.2 (range: 57.9–87.9), 57.5 (range: 46.8–66.9), 65.0 (range: 52.0–92.0) and 57.0 (range: 49.0–66.2) at MF, LF, MT and LT, respectively. The inter-observer correlation coefficient (ICC, 2.1) for the T2 relaxation times of MF was 0.644. Clinical Significance This study offers useful information on T2 relaxation times for articular cartilage of the stifle joint using a 1.5-T MRI in normal dogs.

On the origin of sustained negative BOLD response

2012 ◽  
Vol 108 (9) ◽  
pp. 2339-2342 ◽  
Author(s):  
Marta Moraschi ◽  
Mauro DiNuzzo ◽  
Federico Giove
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Neuronal Activity ◽  
Neural Activity ◽  
Brain Regions ◽  
Bold Response ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Negative Bold

Several brain regions exhibit a sustained negative BOLD response (NBR) during specific tasks, as assessed with functional magnetic resonance imaging. The origin of the NBR and the relationships between the vascular/metabolic dynamics and the underlying neural activity are highly debated. Converging evidence indicates that NBR, in human and non-human primates, can be interpreted in terms of decrease in neuronal activity under its basal level, rather than a purely vascular phenomenon. However, the scarcity of direct experimental evidence suggests caution and encourages the ongoing utilization of multimodal approaches in the investigation of this effect.

In Vivo Proton Relaxation Times Analysis of the Skin Layers by Magnetic Resonance Imaging

1991 ◽  
Vol 97 (1) ◽  
pp. 120-125 ◽  
Author(s):  
Stéphanie Richard ◽  
Bernard Querleux ◽  
Jacques Bittoun ◽  
Ilana Idy-Peretti ◽  
Odile Jolivet ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
Proton Relaxation ◽  
Resonance Imaging

scholarly journals Magnetic Resonance Imaging Assessment of Bone Regeneration in Osseous Defects Filled with Different Biomaterials. An experimental in vivo study

2019 ◽  
Vol 56 (1) ◽  
pp. 235-238
Author(s):  
Tudor Sorin Pop ◽  
Alina Dia Trambitas Miron ◽  
Anca Maria Pop ◽  
Klara Brinzaniuc ◽  
Cristian Trambitas
Keyword(s):  
Magnetic Resonance Imaging ◽  
Stem Cells ◽  
Magnetic Resonance ◽  
Bone Regeneration ◽  
Imaging Modality ◽  
Treatment Options ◽  
Relaxation Times ◽  
Collagen Scaffold ◽  
Resonance Imaging

Noninvasive techniques, such as Magnetic Resonance Imaging (MRI) are becoming more used in the study of bone regeneration outcomes, in both animal models and human patients. Many studies have shown the potential of tissue engineering therapies to promote healing of skeletal injuries, but further research is needed to optimize these treatment options. This investigation is a continuation of other previous published studies, in which critical-sized bone defects created in the parietal bones of Wistar rats were filled with either bioglass or a biologic collagen scaffold seeded both with adipose-derived mesenchymal stem cells. The present study aims to present the applications of MRI in the assessment of the bone regeneration process in these previously created defects, at specific time intervals. MRI techniques are based on the differences between the spin-latice T1 and spin-spin T2 relaxation times of examined specimens or areas, compared to normal tissues. We measured the relaxation times specific to calvarial specimens with a Brukner Minispec. The results showed that the most favorable results were observed when a collagen scaffold seeded with stem cells was used. MRI enabled the detection of hard and even soft tissue changes, these findings suggesting that MRI could be an effective imaging modality for assessing changes in bone morphology and pathobiology. Furthermore, it can be used as an alternative to Computed Tomography in examining the role of various biomaterials used in bone healing, especially when ionizing radiation is contraindicated.

Magnetic resonance imaging quantification and biodistribution of magnetic nanoparticles using T1-enhanced contrast

2018 ◽  
Vol 6 (10) ◽  
pp. 1470-1478 ◽  
Author(s):  
Y. B. Lv ◽  
P. Chandrasekharan ◽  
Y. Li ◽  
X. L. Liu ◽  
J. P. Avila ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Iron Oxide ◽  
Magnetic Nanoparticles ◽  
Magnetic Resonance ◽  
Contrast Agents ◽  
Iron Oxide Nanoparticles ◽  
Relaxation Times ◽  
Oxide Nanoparticles ◽  
Resonance Imaging

Monodispersed 4 nm Gd-doped iron oxide nanoparticles (GdIONPs) were fabricated, and were as T1-weighted contrast agents to confirm the feasibility of non-invasively quantify and monitor IONPs in vivo based on MRI longitudinal relaxation times.

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