Quantification of H217O by 1H-MR imaging at 3 T: a feasibility study

Abstract Background Indirect 1H-magnetic resonance (MR) imaging of 17O-labelled water allows imaging in vivo dynamic changes in water compartmentalisation. Our aim was to describe the feasibility of indirect 1H-MR methods to evaluate the effect of H217O on the MR relaxation rates by using conventional a 3-T equipment and voxel-wise relaxation rates. Methods MR images were used to calculate the R1, R2, and R2* relaxation rates in phantoms (19 vials with different H217O concentrations, ranging from 0.039 to 5.5%). Afterwards, an experimental animal pilot study (8 rats) was designed to evaluate the in vivo relative R2 brain dynamic changes related to the intravenous administration of 17O-labelled water in rats. Results There were no significant changes on the R1 and R2* values from phantoms. The R2 obtained with the turbo spin-echo T2-weighted sequence with 20-ms echo time interval had the higher statistical difference (0.67 s−1, interquartile range 0.34, p < 0.001) and Spearman correlation (rho 0.79). The R2 increase was adjusted to a linear fit between 0.25 and 5.5%, represented with equation R2 = 0.405 concentration + 0.3215. The highest significant differences were obtained for the higher concentrations (3.1–5.5%). The rat brain MR experiment showed a mean 10% change in the R2 value after the H217O injection with progressive normalisation. Conclusions Indirect 1H-MR imaging method is able to measure H217O concentration by using R2 values and conventional 3-T MR equipment. Normalised R2 relative dynamic changes after the intravenous injection of a H217O saline solution provide a unique opportunity to map water pathophysiology in vivo, opening the analysis of aquaporins status and modifications by disease at clinically available 3-T proton MR scanners.

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Adjustable shunt valve–induced magnetic resonance imaging artifact: a comparative study

Journal of Neurosurgery ◽

10.3171/2009.9.jns09171 ◽

2010 ◽

Vol 113 (1) ◽

pp. 74-78 ◽

Cited By ~ 8

Author(s):

Ahmed K. Toma ◽

Andrew Tarnaris ◽

Joan P. Grieve ◽

Laurence D. Watkins ◽

Neil D. Kitchen

Keyword(s):

Mr Imaging ◽

Pulse Sequence ◽

Spin Echo ◽

Pulse Sequences ◽

Fast Spin Echo ◽

Mr Images ◽

Shunt Valve ◽

Adjustable Valve ◽

Imaging Artifact

Object In this paper, the authors' goal was to compare the artifact induced by implanted (in vivo) adjustable shunt valves in spin echo, diffusion weighted (DW), and gradient echo MR imaging pulse sequences. Methods The MR images obtained in 8 patients with proGAV and 6 patients with Strata II adjustable shunt valves were assessed for artifact areas in different planes as well as the total volume for different pulse sequences. Results Artifacts induced by the Strata II valve were significantly larger than those induced by proGAV valve in spin echo MR imaging pulse sequence (29,761 vs 2450 mm3 on T2-weighted fast spin echo, p = 0.003) and DW images (100,138 vs 38,955 mm3, p = 0.025). Artifacts were more marked on DW MR images than on spin echo pulse sequencse for both valve types. Conclusions Adjustable valve–induced artifacts can conceal brain pathology on MR images. This should influence the choice of valve implantation site and the type of valve used. The effect of artifacts on DW images should be highlighted pending the development of less MR imaging artifact–inducing adjustable shunt valves.

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Fast spin-echo MR of the articular cartilage in the osteoarthrotic knee

Acta Radiologica ◽

10.1080/02841859809172164 ◽

1998 ◽

Vol 39 (2) ◽

pp. 120-125 ◽

Cited By ~ 18

Author(s):

Y. Kawahara ◽

M. Uetani ◽

N. Nakahara ◽

Y. Doiguchi ◽

M. Nishiguchi ◽

...

Keyword(s):

Articular Cartilage ◽

Mr Imaging ◽

Correlation Coefficient ◽

Spin Echo ◽

Fast Spin Echo ◽

Mr Images ◽

Articular Surfaces ◽

Arthroscopic Findings ◽

Grade 3 ◽

Fast Spin

Purpose: the objective was to assess the efficacy of fast spin-echo (FSE) imaging in the detection of articular cartilage abnormality in osteoarthrosis of the knee Material and Methods: We studied 356 articular surfaces in 73 knees that had been examined by both MR imaging and arthroscopy. the MR images were obtained with FSE imaging (TR/TE 4200/100) on a 0.5 T unit. the surface abnormalities of the articular cartilage that were detected by MR imaging were compared with the arthroscopic findings Results: the overall sensitivity and specificity of MR in detecting chondral abnormalities were 60.5% (158/261) and 93.7% (89/95) respectively. MR imaging was more sensitive to the higher grade lesions: 31.8% (34/107) in grade 1; 72.4% (71/98) in grade 2; 93.5% (43/46) in grade 3; and 100% (10/10) in grade 4. the MR and arthroscopic grades were the same in 46.9% (167/356), and differed by no more than 1 grade in 90.2% (321/356) and 2 grades in 99.2% (353/356). the correlation between arthroscopic and MR grading scores was highly significant with a correlation coefficient of 0.705 ( p<0.0001) Conclusion: FSE sequence was less sensitive to mild cartilage abnormality but useful in detecting moderate to severe abnormality and in evaluating the degree of articular cartilage abnormality

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Triarylmethyl Radical: EPR Signal to Noise at Frequencies between 250 MHz and 1.5 GHz and Dependence of Relaxation on Radical and Salt Concentration and on Frequency

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2016-0813 ◽

2017 ◽

Vol 231 (4) ◽

Cited By ~ 2

Author(s):

Yilin Shi ◽

Richard W. Quine ◽

George A. Rinard ◽

Laura Buchanan ◽

Sandra S. Eaton ◽

...

Keyword(s):

Spin Relaxation ◽

Electron Spin ◽

Salt Concentration ◽

Spin Echo ◽

Electron Spin Echo ◽

Relaxation Rates ◽

Optimum Frequency ◽

Paramagnetic Resonance ◽

Electron Spin Relaxation

AbstractIn vivo oximetry by pulsed electron paramagnetic resonance is based on measurements of changes in electron spin relaxation rates of probe molecules, such as the triarylmethyl radicals. A series of experiments was performed at frequencies between 250 MHz and 1.5 GHz to assist in the selection of an optimum frequency for oximetry. Electron spin relaxation rates for the triarylmethyl radical OX063 as a function of radical concentration, salt concentration, and resonance frequency were measured by electron spin echo 2-pulse decay and 3-pulse inversion recovery in the frequency range of 250 MHz–1.5 GHz. At constant OX063 concentration, 1/T

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Hyperparathyroidism — Comparison of Flash Imaging with Spin ECHO MR Imaging

Acta Radiologica ◽

10.1177/028418519303400619 ◽

1993 ◽

Vol 34 (6) ◽

pp. 625-630

Author(s):

Y. Noguchi ◽

S. Takashima ◽

J. Ikezoe ◽

M. Yoshii ◽

T. Koide ◽

...

Keyword(s):

Mr Imaging ◽

Spin Echo ◽

Flip Angle ◽

High Signal ◽

Fat Tissue ◽

Mr Images ◽

Flash Sequence ◽

Tissue Contrast ◽

T1 And T2

MR images of the neck were prospectively studied in 19 patients with hyperparathyroidism. Fast low angle shot (FLASH) sequence was performed in addition to T1- and T2-weighted spin echo (SE) sequences. FLASH images were obtained with 320/12/20° (TR/TE/flip angle) using presaturation technique. TE of 12 ms was chosen to eliminate high signal of fat tissue. In the evaluation of detectability, a combination of T1-weighted SE and FLASH images (T1WI + FLASH) was compared with a combination of T1- and T2-weighted SE images (T1WI + T2WI). MR imaging correctly depicted 20 of 30 abnormal glands on both T1WI + FLASH and T1WI + T2WI. FLASH imaging effectively eliminated high signal of fat tissue. Nineteen abnormal glands demonstrated higher signal than surrounding tissues on FLASH images, whereas 12 glands were high-intense on T2-weighted SE images. We conclude that FLASH imaging provides improved tissue contrast and anatomic delineation and, thus, may replace T2-weighted SE imaging in the neck.

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MnDPDP for MR imaging of the liver

Acta Radiologica ◽

10.1080/02841859709172394 ◽

1997 ◽

Vol 38 (5) ◽

pp. 638-642 ◽

Cited By ~ 12

Author(s):

E. J. Rummeny ◽

C. G. Torres ◽

J. C. Kurdziel ◽

G. Nilsen ◽

B. Op de Beeck ◽

...

Keyword(s):

Mr Imaging ◽

Spin Echo ◽

Lesion Detection ◽

Phase Iii ◽

Gradient Echo ◽

Mr Images ◽

Diagnostic Efficacy ◽

Post Contrast ◽

Independent Evaluation ◽

Before And After

Purpose: To evaluate the diagnostic efficacy of mangafodipir trisodium (MnDPDP, Teslascan) as a new contrast agent for MR imaging of the liver based on an independent evaluation of the MR images from the European phase III studies. Material and Methods: MR imaging of the liver was done at 0.5–2.0 T in 17 European centres and included T1-weighted spin-echo and gradient-echo sequences before and after administration of MnDPDP to patients at a dose of 5 μmol/kg b.w. T2-weighted images were also obtained in all cases before the i.v. injection of the agent. Images of a total of 592 patients were evaluated by 4 independent experienced radiologists who were not involved in the on-site clinical trials. Results: Statistically significantly more lesions were detected (p = 0.0014) in MnDP-DP-enhanced T1-weighted MR images than in unenhanced images. T1-weighted gradient-echo sequences were found to be superior to T1-weighted spin-echo sequences after injection of MnDPDP. The post-contrast images were found to be statistically significantly superior to the pre-contrast images in confidence in the presence of a lesion ( p≤ 0.0001), quality of lesion delineation ( p≤ 0.0001), lesion conspicuity ( p ≤ 0.0001) and in the confidence in the diagnosis of a lesion (p = 0.001). Conclusion: This independent evaluation of the European phase III trials confirmed the superiority of MnDPDP-enhanced MR images over unenhanced images for lesion detection and characterization.

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MR Imaging of Skeletal Muscle Hemangiomas

Acta Radiologica ◽

10.1177/02841851960371p129 ◽

1996 ◽

Vol 37 (1P1) ◽

pp. 140-144 ◽

Cited By ~ 5

Author(s):

G. Jenner ◽

V. Söderlund ◽

H. F. C. Bauer ◽

O. Brosjö

Keyword(s):

Skeletal Muscle ◽

Mr Imaging ◽

Spin Echo ◽

Correct Diagnosis ◽

Signal Enhancement ◽

Surgical Staging ◽

Mr Images ◽

Imaging Protocols ◽

Hyperintense Signal ◽

Signal Characteristics

Purpose: Our purpose was to evaluate how MR imaging depicts the vascular fibrofatty structure of hemangiomas. Material and Methods: MR images of 16 histologically proven skeletal muscle hemangiomas were reviewed retrospectively in a nonblinded manner. One patient was examined at 0.5 T, 9 at 1.0 T, and 6 at 1.5 T, and the imaging protocols varied. Results: All lesions were lobulated/tubular. Signal characteristics of fat were seen in 13 lesions as lace-like thin septa within or around the tumor. All 16 studies exhibited a hyperintense signal on T2-weighted spin-echo (SE) (n=15) or T1-weighted fast fat suppressed inversion recovery SE images (n=1). Postcontrast images showed marked signal enhancement in parts of the areas, both of high and low T2-weighted signal. Surgical staging based on MR images was correct in all lesions. Conclusion: MR images display the characteristic vascular fibrofatty structure of hemangiomas and may allow correct diagnosis.

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Development of a Proton-Frequency-Transparent Birdcage Radiofrequency Coil for In Vivo 13C MRS/MRSI Study in a 3.0 T MRI System

Applied Sciences ◽

10.3390/app112311445 ◽

2021 ◽

Vol 11 (23) ◽

pp. 11445

Author(s):

Jun-Sik Yoon ◽

Jong-Min Kim ◽

Han-Jae Chung ◽

You-Jin Jeong ◽

Gwang-Woo Jeong ◽

...

Keyword(s):

Mr Imaging ◽

Corn Oil ◽

Mr Studies ◽

Rf Coil ◽

Mr Images ◽

Hyperpolarized 13C ◽

3.0 T ◽

13C Mrs ◽

3.0 T Mri

A proton-frequency-transparent (PFT) birdcage RF coil that contains carbon-proton switching circuits (CPSCs) is presented to acquire 13C MR signals, which, in turn, enable 1H imaging with existing 1H RF coils without being affected by a transparent 13C birdcage RF coil. CPSCs were installed in the PFT 13C birdcage RF coil to cut the RF coil circuits during 1H MR imaging. Finite-difference time-domain (FDTD) electromagnetic (EM) simulations were performed to verify the performance of the proposed CPSCs. The performance of the PFT 13C birdcage RF coil with CPSCs was verified via phantom and in vivo MR studies. In the phantom MR studies, 1H MR images and 13C MR spectra were acquired and compared with each other using the 13C birdcage RF coil with and without the CPSCs. For the in vivo MR studies, hyperpolarized 13C cardiac MRS and MRSI of swine were performed. The proposed PFT 13C birdcage RF coil with CPSCs led to a percent image uniformity (PIU) reduction of 1.53% in the proton MR images when compared with the case without it. FDTD EM simulations revealed PIU reduction of 0.06% under the same conditions as the phantom MR studies. Furthermore, an SNR reduction of 5.5% was observed at 13C MR spectra of corn-oil phantom using the PFT 13C birdcage RF coil with CPSCs compared with that of the 13C birdcage RF coil without CPSCs. Utilizing the PFT 13C birdcage RF coil, 13C-enriched compounds were successfully acquired via in vivo hyperpolarized 13C MRS/MRSI experiments. In conclusion, the applicability and utility of the proposed 16-leg low-pass PFT 13C birdcage RF coil with CPSCs were verified via 1H MR imaging and hyperpolarized 13C MRS/MRSI studies using a 3.0 T MRI system.

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Deuterium MR in Vivo Imaging of the Rat Eye Using 2H2O

Acta Radiologica ◽

10.1177/028418519503600446 ◽

1995 ◽

Vol 36 (4-6) ◽

pp. 552-555 ◽

Cited By ~ 1

Author(s):

T. Obata ◽

H. Ikehira ◽

F. Shishido ◽

N. Fukuda ◽

Y. Ueshima ◽

...

Keyword(s):

Mr Imaging ◽

Water Movement ◽

Pulse Sequence ◽

Signal To Noise Ratio ◽

Spin Echo ◽

Dynamic Change ◽

Intraperitoneal Administration ◽

Compartment Model

In vivo euterium MR imaging (2H MR) was investigated in rats after intraperitoneal administration of deuterated saline, and a dynamic study of the water movement in rat eyes was performed. Deuterium MR imaging was carried out by means of a gradient-echo (GRE) and a spin-echo (SE) pulse sequence. The rat eye was imaged in 2H MR more selectively by SE than by GRE, but a lower signal-to-noise ratio was obtained in 2H MR imaging using the SE sequence. The MR signal intensity of the rat eye was followed by a 3-compartment model, which enabled determination of the flow rate constant of the water in the eye (0.359/min). Deuterium MR imaging is useful to visualize the dynamic change of water in rat eyes using 2H MR at the same magnetic field (2 T) that can also be used for conventional MR imaging in humans.

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Accounting for biological aggregation in heating and imaging of magnetic nanoparticles

TECHNOLOGY ◽

10.1142/s2339547814500198 ◽

2014 ◽

Vol 02 (03) ◽

pp. 214-228 ◽

Cited By ~ 71

Author(s):

Michael L. Etheridge ◽

Katie R. Hurley ◽

Jinjin Zhang ◽

Seongho Jeon ◽

Hattie L. Ring ◽

...

Keyword(s):

Magnetic Field ◽

Mr Imaging ◽

Fractal Dimensions ◽

Imaging Method ◽

Aggregate Morphology ◽

Fetal Bovine ◽

Aqueous Conditions ◽

Imaging Performance ◽

Phosphate Buffered Saline

Aggregation is a known consequence of nanoparticle use in biology and medicine; however, nanoparticle characterization is typically performed under the pretext of well-dispersed, aqueous conditions. Here, we systematically characterize the effects of aggregation on the alternating magnetic field induced heating and magnetic resonance (MR) imaging performance of iron oxide nanoparticles (IONPs) in non-ideal biological systems. Specifically, the behavior of IONP aggregates composed of ~ 10 nm primary particles, but with aggregate hydrodynamic sizes ranging from 50 nm to 700 nm, was characterized in phosphate buffered saline and fetal bovine serum suspensions, as well as in gels and cells. We demonstrate up to a 50% reduction in heating, linked to the extent of aggregation. To quantify aggregate morphology, we used a combination of hydrodynamic radii distribution, intrinsic viscosity, and electron microscopy measurements to describe the aggregates as quasifractal entities with fractal dimensions in the 1.8–2.0 range. Importantly, we are able to correlate the observed decrease in magnetic field induced heating with a corresponding decrease in longitudinal relaxation rate (R1) in MR imaging, irrespective of the extent of aggregation. Finally, we show in vivo proof-of-principle use of this powerful new imaging method, providing a critical tool for predicting heating in clinical cancer hyperthermia.

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3DFT-Flash MR Imaging of Pancreatic Cancer with Gadopentetate Dimeglumine

Acta Radiologica ◽

10.1177/02841851960371p139 ◽

1996 ◽

Vol 37 (1P1) ◽

pp. 190-194 ◽

Cited By ~ 1

Author(s):

T. Murakami ◽

K. Tsuda ◽

H. Nakamura ◽

K. Osuga ◽

K. Tomoda ◽

...

Keyword(s):

Pancreatic Cancer ◽

Mr Imaging ◽

Spin Echo ◽

Gadopentetate Dimeglumine ◽

Pancreatic Tumors ◽

Breath Hold ◽

Surgical Removal ◽

Slice Thickness ◽

Mr Images ◽

3 Dimensional

Purpose: We evaluated the usefulness of dynamic 3-dimensional Fourier transformation (3DFT) fast low angle shot (FLASH) MR imaging using gadopentetate dimeglumine (Gd-DTPA) to assess the extent of pancreatic cancer. Material and Methods: Breath-hold 3DFT-FLASH MR images (20/4; 25° flip angle; 7 partitions; 3–5-mm slice thickness) were obtained before the administration of 0.1 mmol/kg of Gd-DTPA, just after (early phase), and 1 and 2 min (late phases) after in 14 patients with pancreatic cancer. All patients underwent surgical removal or laparotomy. We compared the findings of T1-, T2-, and postcontrast T1-weighted spin-echo (conventional SE) and 3DFT-FLASH imaging with histologic or surgical findings. Results: Dynamic MR images could delineate the pancreatic tumors more clearly than the conventional SE images, and were useful for diagnosing vessel invasion. The contrast-to-noise ratio between the pancreatic cancer and the surrounding pancreatic parenchyma was significantly higher with the dynamic 3DFT-FLASH image than with the conventional SE images (p<0.01). Conclusion: Dynamic 3DFT-FLASH MR imaging with Gd-DTPA is useful in delineating and evaluating the extent of pancreatic cancer.

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