Application of spin-crossover water soluble nanoparticles for use as MRI contrast agents

Tsukiashi, Asami; Min, Kil Sik; Kitayama, Hikaru; Terasawa, Hiroaki; Yoshinaga, Sosuke; Takeda, Mitsuhiro; Lindoy, Leonard F.; Hayami, Shinya

doi:10.1038/s41598-018-33362-6

Cited by 30 publications

(29 citation statements)

References 19 publications

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“…The observed variations in T 1 and T 2 between field strengths may in part be related to differences in temperature between measurements. The relaxation time temperature coefficients for deionized water were previously measured to be 0.06 s/°C (T 1 ) and 0.01 s/°C (T 2 ), respectively …”

Section: Discussionmentioning

confidence: 99%

Technical Note: T₁ and T₂ and complex permittivities of mineral oil, silicone oil, and glycerol at 0.35, 1.5, and 3 T

Gach

2019

Medical Physics

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Purpose: To identify an inexpensive, low-dielectric liquid for large magnetic resonance imaging (MRI) phantoms that can be used at multiple magnetic field strengths. Methods: The T 1 and T 2 of four candidate phantom liquids (pure mineral oil, food-grade white mineral oil, silicone oil, and glycerol) with low dielectric constants were measured at three field strengths (0.35, 1.5, and 3 T) and extrapolated for 7 T. The complex permittivities of the liquids were measured for frequencies from 13 to 600 MHz. Proton densities were calculated based on molecular weight, proton number, and density. The results were compared to the American College of Radiology (ACR) large MRI phantom electrolyte liquid (10 mM NiCl 2 and 75 mM NaCl in water) and deionized water. The liquids were evaluated based on the NEMA standards (T 1 < 1200 ms, T 2 > 50 ms, proton density within 20% of water, and produces minimal dielectric artifacts). The radiofrequency (RF) wavelengths were computed for each liquid at the four field strengths to determine the risk of dielectric artifacts. Results: The mineral oils were the only liquids to satisfy all of the NEMA guidelines. Excluding deionized water, silicone oil had the longest T 1 and T 2 , and was the most expensive liquid ($200/L). Glycerol had the shortest T 1 and T 2 , and the highest dielectric (excluding the ACR phantom electrolyte and deionized water). All of the liquids except silicone oil met the NEMA proton density guidelines. Conclusions: Food-grade white mineral oil is a good candidate for use in a phantom due to its relaxation times, low dielectric, high proton density, and low cost. Glycerol and deionized water are poor choices for phantom liquids due to their relaxation times and high dielectric constants.

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Section: Discussionmentioning

confidence: 99%

Technical Note: T₁ and T₂ and complex permittivities of mineral oil, silicone oil, and glycerol at 0.35, 1.5, and 3 T

Gach

2019

Medical Physics

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“…Average deviation from the target relaxation times was 98 ms (7.2%) and 112 ms (8.1%) for T 1 , and −4.4 ms (−5.0%) and 2.7 ms (5.4%) for T 2 at 3 and 7 Tesla, respectively. It must be noted that due to changes in the heating systems in both scanner rooms, the temperature at the time of measurement was about 1°C higher compared to the measurements for the model, leading to expected increases in T 1 14,41 …”

Section: Resultsmentioning

confidence: 90%

Technical Note: Human tissue‐equivalent MRI phantom preparation for 3 and 7 Tesla

et al. 2021

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While test objects (phantoms) in MRI are crucial for sequence development, protocol validation and quality control, studies on the preparation of phantoms has been scarce, particularly at fields exceeding 3 Tesla. Here we present a framework for the preparation of phantoms with well-defined T 1 and T 2 times at 3 and 7 Tesla. MethodsPhantoms with varying concentrations of agarose and Gd-DTPA were prepared and measured at 3 and 7 Tesla using T 1 and T 2 mapping techniques. An empirical, polynomial model was constructed that best represents the data at both field strengths, enabling the preparation of new phantoms with specified combinations of both T 1 and T 2 . Instructions for three different tissue types (brain grey matter, brain white matter, and renal cortex) are presented and validated. ResultsT 1 times in the samples ranged from 698ms to 2820ms and from 695ms to 2906ms, whereas T 2 times ranged from 39ms to 227ms and from 34ms to 235ms for 3 and 7 Tesla scans, respectively. Models for both relaxation times used six parameters to represent the data with an adjusted R² of 0.998 and 0.997 for T 1 and T 2 , respectively. ConclusionBased on the equations derived from the current study, it is now possible to obtain accurate weight specifications for a test object with desired T 1 and T 2 relaxation times. This will spare researchers the laborious task of trail-and-error approaches in test object preparation attempts.

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“…It is well known that the T1 value varies with temperature . Therefore, by constructing a system that can be adjusted so that the phantom temperature can be maintained at a level a researcher desires, it is possible to develop a phantom that has a similar T1 value as that of in‐vivo CSF.…”

Section: Discussionmentioning

confidence: 99%

“…This is probably because the T1 value changes due to the fact that the postmortem temperature is lower than the biological temperature. Tsukiashi et al measured the T1 value against the water temperature and reported the change in the temperature and in the T1 value . From this, it is certain that the T1 value largely fluctuates due to changes in temperature.…”

Section: Introductionmentioning

confidence: 99%

Cerebrospinal fluid T1 value phantom reproduction at scan room temperature

Yamashiro

Kobayashi

Saito

2019

J Applied Clin Med Phys

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The T1 value of pure water, which is often used as a phantom to simulate cerebrospinal fluid, is significantly different from that of in‐vivo cerebrospinal fluid. The purpose of this study was to develop a phantom with a T1 value equivalent to that of in‐vivo cerebrospinal fluid under examination room temperature (23°C–25°C). In this study, 1.5 and 3.0 T magnetic resonance imaging scanners were used. We examined the signal intensity change in relation to pure water temperature, the T1 values of acetone‐diluted solutions (0–100 v/v%, in 10 steps), and the correlation coefficients obtained from volunteers and the prepared phantoms. The T1 value was close to the value reported in the literature for cerebrospinal fluid when the acetone‐diluted solution was 70 v/v% or higher at scan room temperature. The value at that time was 3532.81–4704.57 ms at 1.5 T and it ranged from 4052.41 to 5701.61 ms at 3.0 T. The highest correlation with the values obtained from the volunteers was r = 0.993 with pure acetone at 1.5 T and r = 0.991 with acetone 90 v/v% at 3.0 T. The relative error of the best phantom‐volunteer match was 32.61 (%) ± 6.71 at 1.5 T and 46.67 (%) ± 4.31 at 3.0 T. The T1 value measured by the null point method did not detect a significant difference between in vivo CSF and acetone 100 v/v% at 1.5 T and acetone 90 v/v% at 3.0 T. The T1 value of cerebrospinal fluid in the living body at scan room temperature was reproduced with acetone. The optimum concentration of acetone for cerebrospinal‐fluid reproduction was pure acetone at 1.5 T and 90 v/v% at 3.0 T.

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Application of spin-crossover water soluble nanoparticles for use as MRI contrast agents

Cited by 30 publications

References 19 publications

Technical Note: T₁ and T₂ and complex permittivities of mineral oil, silicone oil, and glycerol at 0.35, 1.5, and 3 T

Technical Note: T₁ and T₂ and complex permittivities of mineral oil, silicone oil, and glycerol at 0.35, 1.5, and 3 T

Technical Note: Human tissue‐equivalent MRI phantom preparation for 3 and 7 Tesla

Cerebrospinal fluid T1 value phantom reproduction at scan room temperature

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Application of spin-crossover water soluble nanoparticles for use as MRI contrast agents

Cited by 30 publications

References 19 publications

Technical Note: T1 and T2 and complex permittivities of mineral oil, silicone oil, and glycerol at 0.35, 1.5, and 3 T

Technical Note: T1 and T2 and complex permittivities of mineral oil, silicone oil, and glycerol at 0.35, 1.5, and 3 T

Technical Note: Human tissue‐equivalent MRI phantom preparation for 3 and 7 Tesla

Cerebrospinal fluid T1 value phantom reproduction at scan room temperature

Contact Info

Product

Resources

About

Technical Note: T₁ and T₂ and complex permittivities of mineral oil, silicone oil, and glycerol at 0.35, 1.5, and 3 T

Technical Note: T₁ and T₂ and complex permittivities of mineral oil, silicone oil, and glycerol at 0.35, 1.5, and 3 T