Measurement of Cryoprotectant Concentration Using MRI in Pseudobiological Tissues and Determination of Diffusivity Based on Inverse Problem Analysis

2002 ◽  
Author(s):  
Hiroshi Ishiguro ◽  
Takanori Kai ◽  
Kuniyasu Ogawa
Keyword(s):  
Inverse Problem ◽  
Relaxation Times ◽  
Problem Analysis ◽  
Resonance Imaging ◽  
Volumetric Fraction ◽  
One Dimensional ◽  
Agar Concentration ◽  
Dimensional Distribution ◽  
Magnetic Resonance Imaging Mri

Transient one-dimensional distribution of cryoprotectant concentration in pseudobiological tissues (agar) was measured noninvasively using magnetic resonance imaging (MRI). Cryoprotectants were dimethyl sulfoxide (DMSO) and glycerol, common cryoprotectants penetrating cells. Attenuation of MRI image intensity due to volumetric fraction of solution and relaxation times was also investigated. Apparent diffusivity of each cryoprotectant as a function of agar concentration was determined from the inverse problem analysis. The diffusivity decreased with an increase in agar concentration. This method was also applied to the liver tissues of chicken.

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.

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.

Magnetic Resonance Microscopy of Chemically-Induced Liver Foci

1989 ◽  
Vol 17 (4_part_1) ◽  
pp. 613-616 ◽  
Author(s):  
G. Allan Johnson ◽  
Robert R. Maronpot
Keyword(s):  
Magnetic Resonance ◽  
Imaging Technique ◽  
Relaxation Times ◽  
Basic Research ◽  
Resonance Imaging ◽  
T2 Relaxation ◽  
Spin Lattice ◽  
Chemically Induced ◽  
Magnetic Resonance Imaging Mri

Magnetic resonance imaging (MRI) is a new imaging technique used in clinical diagnosis. This paper describes extension of the technique to basic research applications–specifically detecting and characterizing chemically-induced liver neoplasms and foci of cellular alteration. Two systems have been built that allow spatial microscopic resolution–more than 100,000 x greater than that of earlier efforts. Use of spin-lattice (T1) and spin-spin (T2) relaxation times permits detailed characterization of the tissue.

Determination of one-dimensional distribution of14C-labelled compounds

1988 ◽  
Vol 126 (6) ◽  
pp. 443-453 ◽  
Author(s):  
R. Rexa ◽  
I. Kron ◽  
P. Kralik ◽  
R. Tykva
Keyword(s):  
One Dimensional ◽  
Dimensional Distribution

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 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).

scholarly journals INVERSE PROBLEM OF A ONE-DIMENSIONAL MODEL IN MULTILAYER HEAT CONDUCTION

2020 ◽  
Vol 19 (1) ◽  
pp. 42
Author(s):  
G. C. Oliveira ◽  
S. S. Ribeiroa ◽  
G. Guimarães
Keyword(s):  
Inverse Problem ◽  
Measurement Errors ◽  
Input Data ◽  
Temperature Measurements ◽  
Dimensional Model ◽  
One Dimensional ◽  
Ill Posed ◽  
Measurements Errors ◽  
Chip Chip

The inverse problem in conducting heat is related to the determination of the boundary condition, rate of heat generation, or thermophysical properties, using temperature measurements at one or more positions of the solid. The inverse problem in conducting heat is mathematically one of the ill-posed problems, because its solution extremely sensitive to measurement errors. For a well-placed problem the following conditions must be satisfied: the solution must exist, it must be unique and must be stable on small changes of the input data. The objective of the work is to estimate the heat flux generated at the tool-chip-chip interface in a manufacturing process. The term "estimation" is used because in the temperature measurements, errors are always present and these affect the accuracy of the calculation of the heat flow.

scholarly journals Comparison of radiography and magnetic resonance imaging in the diagnosis of hand osteoarthritis

2019 ◽  
Vol 57 (1) ◽  
pp. 91-99 ◽  
Author(s):  
D. M. Kudinsky ◽  
A. V. Smirnov ◽  
L. I. Alekseeva
Keyword(s):  
Magnetic Resonance Imaging ◽  
Articular Cartilage ◽  
Magnetic Resonance ◽  
Bone Marrow Edema ◽  
Soft Tissues ◽  
Joint Space ◽  
Hand Osteoarthritis ◽  
Resonance Imaging ◽  
Magnetic Resonance Imaging Mri

The article discusses the possibilities and search for the optimal concept of diagnosis of hand osteoarthritis (OA). The data of numerous studies with focus on the comparison of sensitivity and specificity of the main techniques in this type of pathology – standard radiography and magnetic resonance imaging (MRI) are presented. Determination of the earliest symptoms of OA allows to predict the development of the disease and begin its therapy. The joint space narrowing due to the loss of articular cartilage is the earliest radiological symptom of OA, which is observed in the advanced stage of the disease. MRI, unlike radiography, makes it possible to visualize the articular cartilage, fluid in the joint cavity, bone marrow edema and soft tissues, but it is more expensive and time-consuming method. At present the main difficulty lies in the absence of a standardized system for assessing the MRI hand OA manifestations, as well as insufficient number of investigations in this area.

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