Measurement of Liver Iron Concentration by MRI Is Reproducible

Alústiza, J.M.; Emparanza, José Ignacio; Castiella, Agustín; Casado, Alfonso; Garrido, Adolfo Jiménez; Aldazábal, P; Vicente, M. San; Garcia, N. Andres; Asensio, Ana Belén; Salvador, E.; Moyua, Aranzazu; Arozena, X.; Zarco, Miguel; L, Jauregui; Vicente, Ohiana

doi:10.1155/2015/294024

Cited by 16 publications

(18 citation statements)

References 19 publications

(29 reference statements)

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“…5 Additionally, reproducibility of MRI-derived LIC estimates has been shown to be superior to that of biopsy measurements. [6][7][8][9] Understanding the potential limitations and performance of R2* quantitation for LIC estimation is valuable when implementing this diagnostic tool at large sites. and R2* are closely correlated with LIC using data acquired on a 1.5 T MRI system.…”

Section: Introductionmentioning

confidence: 99%

“…6 Alústiza et al found that a signal intensity ratio (SIR) method of calculating LIC is reproducible on several different 1.5 T systems. 7 Therefore, various studies have shown that MR image analysis can be used in conjunction with specified image acquisition techniques to estimate patient LIC. Furthermore, intramachine reproducibility of those measurements has been demonstrated.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, intramachine reproducibility of those measurements has been demonstrated. [5][6][7] However, evidence of intermachine reproducibility was not extended to R2* estimation techniques. While these studies do not represent an exhaustive search of all published evidence, an extensive literature review suggests further study is warranted concerning intermachine reproducibility of LIC measurements based on R2* quantification.…”

Section: Introductionmentioning

confidence: 99%

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Reproducibility of liver iron concentration estimates in MRI through R2* measurement determined by least‐squares curve fitting

Headley

Pickens

2020

J Applied Clin Med Phys

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Measuring transverse relaxation rate (R2* = 1/T2*) via MRI allows for noninvasive evaluation of multiple clinical parameters, including liver iron concentration (LIC) and fat fraction. Both fat and iron contribute to diffuse liver disease when stored in excess in the liver. This liver damage leads to fibrosis and cirrhosis with an increased risk of developing hepatocellular carcinoma. Liver iron concentration is linearly related to R2* measurements using MRI. A phantom was constructed to assess R2* quantification variability on 1.5 and 3 T MRI systems. Quantification was executed using least-squares curve fitting techniques. The phantom was created using readily available, low-cost materials. It contains four vials with R2* values that cover a clinically relevant range (100 to 420 Hz at 1.5 T). Iron content was achieved using ferric chloride solutions contained in glass vials, each affixed in a three-dimensional (3D)printed polylactide (PLA) structure, surrounded by distilled water, all housed in a sealed acrylic cylinder. Multiple phantom stands were also 3D-printed using PLA for precise orientation of the phantom with respect to the direction of the static magnetic field. Acquisitions at different phantom angles, across multiple MRI systems, and with different pulse sequence parameters were evaluated. The variability between any two R2* measurements, taken in the same vial under these various acquisition conditions, on a 1.5 T MRI system, was <7% for each of the four vials. For 3 T MRI systems, variability was less than 14% in all cases. Variability was <6% for both 1.5 and 3 T acquisitions when unchanged pulse sequence parameters were used. The phantom can be used to mimic a range of clinically relevant levels of R2* relaxation rates, as measured using MRI. These measurements were found to be reproducible relative to the gold-standard method, liver biopsy, across several different image acquisition conditions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Reproducibility of liver iron concentration estimates in MRI through R2* measurement determined by least‐squares curve fitting

Headley

Pickens

2020

J Applied Clin Med Phys

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“…The material should be stable over a period of time and without signal interference [3]. Several transition metals were applied as paramagnetic contrast agents to prepare phantoms with desired T 1 and T 2 values such as nickel [4], gadolinium [3] and iron [5] compounds. Nevertheless, only one type of metal was developed as magnetic nanoparticle contrast agent, Ferumoxides-for MRI phantom [6].…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, only one type of metal was developed as magnetic nanoparticle contrast agent, Ferumoxides-for MRI phantom [6]. However, these particles lack the reliable stability due to the precipitation of irons at the bottom of the tubes in the phantom [5].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of SPIO-loaded PEG-b-PS micelles as contrast agent for long-term nanoparticle-based MRI phantom

Theerasilp

Sungkarat

2018

Bull Mater Sci

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Nanoparticle-based magnetic resonance imaging (MRI) phantom was developed from the suspension of magnetic nanoparticles composing methoxy poly(ethylene glycol)-block-poly(styrene) (PEG-b-PS) micelles and superparamagnetic iron oxide (SPIO) nanoparticles in the core of micelles. The size of SPIO-loaded micelles was determined by dynamic light scattering (DLS) and transmission electron microscopy. Larger-size micelles were found when SPIO loading was increased. The effect of the hydrophobic section of block copolymer on the size of micelles was studied by DLS. Transverse relaxivity was evaluated on both 1.5 and 3 T clinical MRI scanner. Higher SPIO-loading provided higher relaxivity, where the relaxivity of 10% SPIO-loaded PEG(5 kDa)-b-PS(5 kDa) were 144.0 and 174.0 m M −1 s −1 for 1.5 and 3 T MRI, respectively. This formulation showed stability over a 10-week period, and the standard deviations of the relaxivities were 3.0 and 8.0% for 1.5 and 3 T MRI, respectively. Thus, SPIO-loaded PEG-b-PS micelles have a potential to be applied as a contrast agent for nanoparticle-based MRI phantom.

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Evaluation of Hepatic Iron Overload Using a Contemporary 0.55 T MRI System

Campbell-Washburn

Mancini

Conrey

et al. 2021

Magnetic Resonance Imaging

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Background MRI T2* and R2* mapping have gained clinical acceptance for noninvasive assessment of iron overload. Lower field MRI may offer increased measurement dynamic range in patients with high iron concentration and may potentially increase MRI accessibility, but it is compromised by lower signal‐to‐noise ratio that reduces measurement precision. Purpose To characterize a high‐performance 0.55 T MRI system for evaluating patients with liver iron overload. Study Type Prospective. Population Forty patients with known or suspected iron overload (sickle cell anemia [n = 5], ß‐thalassemia [n = 3], and hereditary spherocytosis [n = 2]) and a liver iron phantom. Field strength/sequence A breath‐held multiecho gradient echo sequence at 0.55 T and 1.5 T. Assessment Patients were imaged with T2*/R2* mapping 0.55 T and 1.5 T within 24 hours, and 16 patients returned for follow‐up exams within 6–16 months, resulting in 56 paired studies. Liver T2* and R2* measurements and standard deviations were compared between 0.55 T and 1.5 T and used to validate a predictive model between field strengths. The model was then used to classify iron overload at 0.55 T. Statistical Tests Linear regression and Bland–Altman analysis were used for comparisons, and measurement precision was assessed using the coefficient of variation. A P‐value < 0.05 was considered statistically significant. Results R2* was significantly lower at 0.55 T in our cohort (488 ± 449 s−1 at 1.5 T vs. 178 ± 155 s−1 at 0.55 T, n = 56 studies) and in the patients with severe iron overload (937 ± 369 s−1 at 1.5 T vs. 339 ± 127 s−1 at 0.55 T, n = 23 studies). The coefficient of variation indicated reduced precision at 0.55 T (3.5 ± 2.2% at 1.5 T vs 6.9 ± 3.9% at 0.55 T). The predictive model accurately predicted 1.5 T R2* from 0.55 T R2* (Bland Altman bias = −6.6 ± 20.5%). Using this model, iron overload at 0.55 T was classified as: severe R2* > 185 s−1, moderate 81 s−1 < R2* < 185 s−1, and mild 45 s−1 < R2* < 91 s−1. Data Conclusion We demonstrated that 0.55 T provides T2* and R2* maps that can be used for the assessment of liver iron overload in patients. Evidence Level 2 Technical Efficacy Stage 2

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Measurement of Liver Iron Concentration by MRI Is Reproducible

Cited by 16 publications

References 19 publications

Reproducibility of liver iron concentration estimates in MRI through R2* measurement determined by least‐squares curve fitting

Reproducibility of liver iron concentration estimates in MRI through R2* measurement determined by least‐squares curve fitting

Synthesis and characterization of SPIO-loaded PEG-b-PS micelles as contrast agent for long-term nanoparticle-based MRI phantom

Evaluation of Hepatic Iron Overload Using a Contemporary 0.55 T MRI System

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