An MRI phantom material for quantitative relaxometry

Kraft, Kenneth A.; Fatouros, Panos P.; Clarke, Geoffrey D.; Kishore, P. R. S.

doi:10.1002/mrm.1910050606

Cited by 97 publications

(89 citation statements)

References 23 publications

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“…Phantoms of 2% (w/v) agar dissolved in nanopure (distilled and deionized) water, 0.01% (w/v) NaCl and various molar concentrations of gadopentetate dimeglumine (Gd-DTPA) were created in 50-mL centrifuge tubes. First, the agar powder was dissolved in 50 mL of nanopure water at 55-60 C and heated until 85 C for 5 min on a combined hotplate/magnetic stirrer until the solution became clear (19)(20)(21). Following the addition of NaCl, Gd-DTPA (MagnevistV R ) was then added at concentrations ranging from 0 to 2.0 mM (v/v) per tube to alter T 1 relaxivity and stirred for one minute.…”

Section: Tissue Modelmentioning

confidence: 99%

A novel MRI‐compatible brain ventricle phantom for validation of segmentation and volumetry methods

Khan

Drozd

Moreland

et al. 2012

Magnetic Resonance Imaging

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and the Alzheimer's Disease Neuroimaging InitiativePurpose: To create a standardized, MRI-compatible, lifesized phantom of the brain ventricles to evaluate ventricle segmentation methods using T 1 -weighted MRI. An objective phantom is needed to test the many different segmentation programs currently used to measure ventricle volumes in patients with Alzheimer's disease. Materials and Methods:A ventricle model was constructed from polycarbonate using a digital mesh of the ventricles created from the 3 Tesla (T) MRI of a subject with Alzheimer's disease. The ventricle was placed in a brain mold and surrounded with material composed of 2% agar in water, 0.01% NaCl and 0.0375 mM gadopentetate dimeglumine to match the signal intensity properties of brain tissue in 3T T 1 -weighted MRI. The 3T T 1 -weighted images of the phantom were acquired and ventricle segmentation software was used to measure ventricle volume. Results:The images acquired of the phantom successfully replicated in vivo signal intensity differences between the ventricle and surrounding tissue in T 1 -weighted images and were robust to segmentation. The ventricle volume was quantified to 99% accuracy at 1-mm voxel size. Conclusion:The phantom represents a simple, realistic and objective method to test the accuracy of lateral ventricle segmentation methods and we project it can be extended to other anatomical structures.

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Section: Tissue Modelmentioning

confidence: 99%

A novel MRI‐compatible brain ventricle phantom for validation of segmentation and volumetry methods

Khan

Drozd

Moreland

et al. 2012

Magnetic Resonance Imaging

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“…The Ni 2+ concentration in the stock solution was 5.3 mM, which should result in a T 1 relaxation time of approximately 300 ms (Morgan and Nolle 1959). The use of agarose gel instead of an aqueous solution shortens T 2 but should not affect T 1 (Kraft et al 1987). The polyvinylacetate and ink concentrations were 4% and 1% respectively.…”

Section: Influence Of Optical Dopants On Mr Images and Relaxation Timesmentioning

confidence: 99%

MRI thermometry in phantoms by use of the proton resonance frequency shift method: application to interstitial laser thermotherapy

et al. 1998

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In this work the temperature dependence of the proton resonance frequency was assessed in agarose gel with a high melting temperature (95 • C) and in porcine liver in vitro at temperatures relevant to thermotherapy (25-80 • C). Furthermore, an optically tissue-like agarose gel phantom was developed and evaluated for use in MRI. The phantom was used to visualize temperature distributions from a diffusing laser fibre by means of the proton resonance frequency shift mehod. An approximately linear relationship (0.0085 ppm • C −1 ) between proton resonance frequency shift and temperature change was found for agarose gel, whereas deviations from a linear relationship were observed for porcine liver. The optically tissue-like agarose gel allowed reliable MRI temperature monitoring, and the MR relaxation times (T 1 and T 2 ) and the optical properties were found to be independently alterable. Temperature distributions around a diffusing laser fibre, during irradiation and subsequent cooling, were assessed with high spatial resolution (voxel size = 4.3 mm 3 ) and with random uncertainties ranging from 0.3 • C to 1.4 • C (1 SD) with a 40 s scan time.

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“…Therefore, a phantom that behaves similarly to human soft tissue functions as a replacement. The optimal characteristics of MRI phantoms used for such purposes are as follows: (1) relaxation times equivalent to those of human tissues, (2) dielectric properties equivalent to those of human tissues, (3) the relaxation times and dielectric properties should be homogeneous throughout the phantom, (4) mechanical properties suitable for fabrication of a human torso without the need for reinforcement, (5) can be used to form shapes of human organs, (6) ease of handling, and (7) stability of physical and imaging properties over an extended period. 1 Over the last few decades, several studies have been conducted on water-based polymer gels with paramagnetic ions as potential materials for MRI phantoms.…”

Section: Introductionmentioning

confidence: 99%

“…The T 1 and T 2 relaxation times represent the rate at which the longitudinal and transverse components of the magnetization vector of human tissue return to thermodynamic equilibrium. Some polymer gels that have been investigated include agarose, 2-4 agar, 5,6 polyvinyl alcohol, 7 gelatin, 8 and polysaccharide gels TX-150 9 and TX-151. 10 These studies have demonstrated that each material has potential for phantom application, but this is limited due to fragility and storage conditions.…”

Section: Introductionmentioning

confidence: 99%

Mechanical stability analysis of carrageenan-based polymer gel for magnetic resonance imaging liver phantom with lesion particles

Naguib

Haider

2014

J. Med. Imag

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Abstract. Medical imaging is an effective technique used to detect and prevent disease in cancer research. To optimize medical imaging, a calibration medium or phantom with tissue-mimicking properties is required. Although the feasibility of various polymer gel materials has previously been studied, the stability of the gels' properties has not been investigated. In this study, we fabricated carrageenan-based polymer gel to examine the stability of its properties such as density, conductivity, permittivity, elastic modulus, and T 1 and T 2 relaxation times over six weeks. We fabricated eight samples with different carrageenan and agar concentrations and found that the density, elastic modulus, and compressive strength fluctuated with no specific pattern. The elastic modulus in sample 4 with 3 wt. % carrageenan and 1.5 wt. % agar fluctuated from 0.51 to 0.64 MPa in five weeks. The T 1 and T 2 relaxation times also varied by 23% to 29%. We believe that the fluctuation of these properties is related to the change in water content of the sample due to cycles of water expulsion and absorption in their containers. The fluctuation of the properties should be minimized to achieve accurate calibration over the shelf life of the phantom and to serve as the standard for quality assurance. Furthermore, a full liver phantom with spherical lesion particles was fabricated to demonstrate the potential for phantom production.

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An MRI phantom material for quantitative relaxometry

Cited by 97 publications

References 23 publications

A novel MRI‐compatible brain ventricle phantom for validation of segmentation and volumetry methods

A novel MRI‐compatible brain ventricle phantom for validation of segmentation and volumetry methods

MRI thermometry in phantoms by use of the proton resonance frequency shift method: application to interstitial laser thermotherapy

Mechanical stability analysis of carrageenan-based polymer gel for magnetic resonance imaging liver phantom with lesion particles

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