scholarly journals Temperature monitoring through nanoparticle-activated proton relaxation for magnetic resonance imaging application

2021 ◽  
Vol 2058 (1) ◽  
pp. 012036
Author(s):  
A D Mironova ◽  
Yu V Kargina ◽  
A M Perepukhov ◽  
O S Pavlova ◽  
M V Gulyaev ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Pure Water ◽  
Relaxation Times ◽  
Effect Of Temperature ◽  
Proton Relaxation ◽  
Resonance Imaging ◽  
Pure Silicon ◽  
Imaging Application ◽  
Magnetic Resonance Imaging Mri

Abstract An effect of temperature on the proton relaxation times in aqueous suspensions of solid-state nanoparticles (NPs) is comparatively investigated for the NPs’ composition varied from pure silicon (Si) with natural isotope content to Si with iron impurities as well as for Si NPs enriched with Si-29 isotope. For all types of the investigated NPs both the longitudinal and transverse relaxation times become shorter compared with that for pure water because of the interaction of electron spin centers in those NPs with nuclear spins of the protons in water molecules. The obtained results allow us to evaluate the temperature sensitivity of NP-based systems for their biomedical applications in magnetic resonance imaging (MRI).

Switchable 19F MRI polymer theranostics: towards in situ quantifiable drug release

2017 ◽  
Vol 8 (34) ◽  
pp. 5157-5166 ◽  
Author(s):  
A. V. Fuchs ◽  
A. P. Bapat ◽  
G. J. Cowin ◽  
K. J. Thurecht
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Hyperbranched Polymer ◽  
Relaxation Times ◽  
Mri Contrast Agent ◽  
Resonance Imaging ◽  
Mri Contrast ◽  
19F Mri ◽  
Magnetic Resonance Imaging Mri

A switchable polymeric 19F magnetic resonance imaging (MRI) contrast agent was synthesised whereby the transverse (T2) relaxation times increased as a therapeutic was released from a hyperbranched polymer (HBP) scaffold.

scholarly journals Magnetic Resonance Imaging of Hepatic Neoplasms in the Rat

1989 ◽  
Vol 26 (4) ◽  
pp. 303-308 ◽  
Author(s):  
G. A. Johnson ◽  
M. B. Thompson ◽  
G. P. Cofer ◽  
D. Campen ◽  
R. R. Maronpot
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
Three Dimensional ◽  
Resonance Imaging ◽  
Focal Lesions ◽  
Hepatic Neoplasms ◽  
Histologic Evaluation ◽  
Repetition Time ◽  
Magnetic Resonance Imaging Mri

Magnetic resonance imaging (MRI) at microscopic resolution was done on a live rat that had chemically induced hepatic neoplasms. Beginning at the anterior aspect of the liver, 16 contiguous transaxial slices (each 1.25 mm thick) were produced using three-dimensional Fourier transform sequences. The rat had been treated with diethylnitrosamine (200 mg/kg) at 70 days of age, and, subsequently, received periodic implants of 17a-ethynylestradiol for 60 weeks. Carr-Purcell-Meiboom-Gill (CPMG) sequences (repetition time = 2,000 and echo time = 20, 40, 60, 80 ms) were done to give quantitative measures of spin-spin relaxation times (T2). Pixel-by-pixel curve fitting from these multiple images yielded calculated T2 images. Histologic evaluation of three abnormal areas in the liver revealed solid and cystic hepatocellular adenomas. Although lesions were evident in early-echo images of the CPMG sequence, they were more apparent in the late-echo images. This was consistent with longer T2 relaxation times for the lesions. The voxels of dimensions (230 × 230 × 1,250 /μm) permitted resolution of volume elements <0.07 mm3. This in turn permitted clear delineation of focal lesions <3 mm in diameter. The potential for MRI at microscopic resolution in toxicologic research is clearly demonstrated.

scholarly journals Magnetic Resonance Imaging Property of Doxorubicin-Loaded Gadolinium/13X Zeolite/Folic Acid Nanocomposite

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
S Ghaderi
Keyword(s):  
Magnetic Resonance Imaging ◽  
Folic Acid ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
A549 Cells ◽  
In Vitro Study ◽  
Resonance Imaging ◽  
13X Zeolite ◽  
Magnetic Resonance Imaging Mri

Abstract Background: Magnetic resonance imaging (MRI) using nanostructures has been a proper method for tumor targeting purposes. Different MRI nanomaterials, targeting agents and anticancer drugs have been used for targeting of tumors. Objectives: This study aims to consider the MRI property of doxorubicin (DOX)-loaded gadolinium/13X zeolite/folic acid (Gd3+/13X/FA) nanocomposite. Material and Methods: In this in vitro study, Gd3+/13X/FA/DOX nanocomposite was prepared and the X-ray diffraction, scanning electron microscopy and MTT assay were conducted to evaluate the physicochemical properties of the nanocomposite. MRI was performed at 25°C using a 1.5 T clinical system to determine the T1 relaxation times and subsequently, the T1 relaxivity. Results: The size of the nanocomposite was in the range of 80-200 nm. The nanocomposite without DOX loading (Gd3+/13X/FA) showed compatibility for A549 cells for all concentrations while DOX-loaded nanocomposite was toxic for 62% of the cells at the concentration of 0.4 mg/ml. The T1 relaxivity of Gd3+/13X/FA/DOX nanocomposite was 4.0401 mM-1s-1. Conclusion: Gd3+/13X/FA/DOX nanocomposite shows a T1 relaxivity similar to the conventional gadolinium chelates, and a successful DOX loading.

scholarly journals MCF-7, ACHN, and A549 Cancer Cells Characterized by Quantitative Magnetic Resonance Imaging In Vitro

2021 ◽  
Vol 12 (4) ◽  
pp. 5174-5186
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Cancer Cells ◽  
Relaxation Times ◽  
Resonance Imaging ◽  
T1 And T2 ◽  
Magnetic Resonance Imaging Mri ◽  
Mcf 7

To work with cancer cell cultures in vitro at 1.5 Tesla Magnetic Resonance Imaging (MRI), it was necessary to develop dedicated receiver coils. This device allowed to adjust the shape of the tested objects and thus improve the quality of imaging. One of the conditions for this new device was to increase the recorded signal level and reduce the distance between the tested object and the receiving elements of the coil. MCF7 (breast adenocarcinoma, Her-2 positive), ACHN (kidney cancer cells), and A549 (lung cancer cells) were characterized by using magnetic resonance imaging (MRI) in vitro. MRI measurements were performed using the clinical scanner with a 1.5 Tesla magnetic field. MCF-7, ACHN, and A549 cancer cells were characterized by T1 and T2 relaxation times. For MCF-7 cells, the relaxation times T1 and T2 were 2360 ± 12 ms and 116 ± 0.9 ms, respectively. For ACHN cells, the relaxation times T1 and T2 were 1354 ± 193 ms and 80 ± 9 ms, respectively. Values of T1 and T2 for A549 cancer cells cultures were 1527 ± 59 ms and 150 ± 8 ms, respectively. Once an accurate pulse protocol has been established and satisfactory reproducibility was obtained, the determination of relaxation times can be used as a tool to monitor cancer cell cultures using MRI in vitro based on the determination of changes in relaxation times.

A Study of Epileptic Psychosis Using Magnetic Resonance Imaging

1990 ◽  
Vol 156 (2) ◽  
pp. 231-235 ◽  
Author(s):  
P. Conlon ◽  
M. R. Trimble ◽  
D. Rogers
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Temporal Lobe ◽  
Relaxation Times ◽  
Control Group ◽  
Resonance Imaging ◽  
Left Temporal Lobe ◽  
Magnetic Resonance Imaging Mri ◽  
Patients With Epilepsy ◽  
State Examination

Magnetic resonance imaging (MRI) was used in patients with epilepsy and psychosis. From 50 patients with epilepsy, a subgroup of 12 patients were categorised by the Present State Examination (PSE) as having nuclear schizophrenia (NS) and then compared with an epileptic control group with no psychiatric history. Further, patients with hallucinations were compared with patients without hallucinations. No differences in T1 relaxation times in any regions of interest were noted in the NS group compared with the other group. However, patients with hallucinations had a significantly higher T1 value in the left temporal lobe. These findings support the concept that specific abnormalities in limbic system structures relate to the phenomenology of the psychoses of epilepsy, especially left temporal lobe epilepsy.

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.

scholarly journals Nanoparticle-Based Paramagnetic Contrast Agents for Magnetic Resonance Imaging

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Juan Pellico ◽  
Connor M. Ellis ◽  
Jason J. Davis
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Contrast Agents ◽  
Imaging Modality ◽  
Relaxation Times ◽  
Deep Penetration ◽  
Resonance Imaging ◽  
Tissue Contrast ◽  
Recent Developments ◽  
Magnetic Resonance Imaging Mri

Magnetic resonance imaging (MRI) is a noninvasive medical imaging modality that is routinely used in clinics, providing anatomical information with micron resolution, soft tissue contrast, and deep penetration. Exogenous contrast agents increase image contrast by shortening longitudinal (T1) and transversal (T2) relaxation times. Most of the T1 agents used in clinical MRI are based on paramagnetic lanthanide complexes (largely Gd-based). In moving to translatable formats of reduced toxicity, greater chemical stability, longer circulation times, higher contrast, more controlled functionalisation and additional imaging modalities, considerable effort has been applied to the development of nanoparticles bearing paramagnetic ions. This review summarises the most relevant examples in the synthesis and biomedical applications of paramagnetic nanoparticles as contrast agents for MRI and multimodal imaging. It includes the most recent developments in the field of production of agents with high relaxivities, which are key for effective contrast enhancement, exemplified through clinically relevant examples.

Advances in Magnetic Resonance Imaging of the Pelvis at 0.15 Tesla

1986 ◽  
Vol 27 (4) ◽  
pp. 369-377 ◽  
Author(s):  
D. J. Hamlin ◽  
H. Pettersson ◽  
J. O. Johnson ◽  
J. R. Fitzsimmons
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Relaxation Times ◽  
Resonance Imaging ◽  
T2 Relaxation ◽  
Low Field ◽  
Radiofrequency Coils ◽  
Magnetic Resonance Imaging Mri ◽  
Mass Lesions

The recent development of improved commercial radiofrequency coils and multiecho, multislice software for low field strength magnetic resonance systems has markedly increased the clinical utility of magnetic resonance imaging (MRI) of the pelvis at low field strengths. An evaluation of 70 patients with a variety of pelvic lesions and 14 normal volunteers who were studied using 0.15 T resistive magnet scanner revealed that anatomic structures and a variety of mass lesions could be clearly depicted in transaxial, sagittal and coronal planes using this updated system. Accurate characterization of lesions was possible in many instances using T2 weighted multiecho scans with echo time (TE) ranging from 30 ms to 120 ms (45 ms–180 ms using a reduced bandwidth technique). T1 weighted multislice scans demonstrated anatomic structures to best adantage and calculation of T1 and T2 relaxation times frequently facilitated more accurate differential diagnosis, particularly in the case of ovarian lesions.

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

INVERSION RECOVERY GRADIENT ECHO PULSE SEQUENCE PROGRAM ON A 0.7 TESLA OPEN SUPERCONDUCTING MAGNETIC RESONANCE IMAGING PLATFORM

2016 ◽  
Vol 16 (08) ◽  
pp. 1640020
Author(s):  
SHUO LI ◽  
YANCHUN ZHU ◽  
JIE YANG ◽  
YAOQIN XIE ◽  
SONG GAO
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Pulse Sequence ◽  
Pure Water ◽  
Pulse Sequences ◽  
Inversion Recovery ◽  
Resonance Imaging ◽  
Gradient Echo ◽  
Recovery Times ◽  
Magnetic Resonance Imaging Mri

The newly developed open superconducting magnetic resonance imaging (MRI) system, which combines the advantages of the high magnetic fields of superconducting MRI systems and open characteristics of permanent MRI systems, has great potential in clinical and research applications. However, few pulse sequences are applicable to this system. In addition, further testing on this system is needed. Therefore, in this paper, an inversion recovery gradient echo (IR-GE) pulse sequence was developed based on the features of the 0.7 Tesla open superconducting MRI system. An MR Solutions spectrometer was used to control the IR-GE pulse sequence. The developed IR-GE pulse sequence was applied to a pure water phantom using different inversion recovery times (TI). The results of the theoretical analysis and experiments indicate that the developed IR-GE pulse sequence could be effectively applied to the 0.7 Tesla open superconducting MRI system.

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