Objectives To explore the reproducibility of the 1.5-T MR imaging (MRI)-based R2* method in measuring the liver iron concentration (LIC) across different MRI scanners, scan parameters, and postprocessing techniques. Materials and methods We performed a systematic search of the PubMed, Embase, Medline, Cochrane Library, and Web of Science databases and identified studies that used the 1.5-T MRI-based R2* method to measure the LIC. The original data were extracted from the selected studies. Reproducibility was assessed in terms of the ability to replicate the measured LIC with the 1.5-T MRI-based R2* method across different scanning instruments, scan parameters, and postprocessing techniques. We used the scanner equipment, scan parameters, and postprocessing technique as random effects to determine whether the R2* values obtained in the different studies were significantly different after the effects of the measured LIC were excluded. The calibration curve that best fit the R2* value to the LIC was estimated via univariate regression. Results Twenty-one studies (1147 participants) were included. The seven studies (435 participants) in which the initial TE was ≤ 1.0 ms and the TE spacing was ≤ 1.4 ms did not have significant differences in the measured R2* value in pairwise comparisons (p > 0.05). Calibration of R2* to LIC was as follows: LIC (mg/g) = 0.042 + 2.85 × 10−2 R2* (s−1) (R2 = 0.79). Conclusion The 1.5-T MRI-based R2* method in estimating LIC was reproducible across different MRI scanners, scan parameters, and postprocessing techniques. Key Points <Emphasis Type="BoldItalic">Question</Emphasis> The R2* method is widely used to quantify LIC, but the reproducibility of R2-based LIC estimation remains unknown. <Emphasis Type="BoldItalic">Findings</Emphasis> In scan sequences with an initial echo time (TE) ≤ 1.0 ms and a TE spacing ≤ 1.4 ms, the R2-based LIC quantification at 1.5 T achieved good reproducibility. <Emphasis Type="BoldItalic">Clinical relevance</Emphasis> The 1.5-T MRI-based R2* method enables reproducible quantification of the LIC; its reproducibility spares patients from unnecessary trauma and economic burdens while promoting the extensive clinical dissemination of R2*-based LIC quantification methods. Graphical Abstract

Reproducibility of liver iron concentration measured by R2* method based on 1.5-T MRI: a meta-analysis

期刊论文
发表日期：

2025年1月3日

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Sue Cao,
Jie Zhang,
Chenyu Dong,
Yutao Que,
Xin Gao,
Ruomi Guo

摘要

Objectives

To explore the reproducibility of the 1.5-T MR imaging (MRI)-based R2* method in measuring the liver iron concentration (LIC) across different MRI scanners, scan parameters, and postprocessing techniques.

Materials and methods

We performed a systematic search of the PubMed, Embase, Medline, Cochrane Library, and Web of Science databases and identified studies that used the 1.5-T MRI-based R2* method to measure the LIC. The original data were extracted from the selected studies. Reproducibility was assessed in terms of the ability to replicate the measured LIC with the 1.5-T MRI-based R2* method across different scanning instruments, scan parameters, and postprocessing techniques. We used the scanner equipment, scan parameters, and postprocessing technique as random effects to determine whether the R2* values obtained in the different studies were significantly different after the effects of the measured LIC were excluded. The calibration curve that best fit the R2* value to the LIC was estimated via univariate regression.

Results

Twenty-one studies (1147 participants) were included. The seven studies (435 participants) in which the initial TE was ≤ 1.0 ms and the TE spacing was ≤ 1.4 ms did not have significant differences in the measured R2* value in pairwise comparisons (p > 0.05). Calibration of R2* to LIC was as follows: LIC (mg/g) = 0.042 + 2.85 × 10⁻² R2* (s⁻¹) (R² = 0.79).

Conclusion

The 1.5-T MRI-based R2* method in estimating LIC was reproducible across different MRI scanners, scan parameters, and postprocessing techniques.

Key Points

Question The R2* method is widely used to quantify LIC, but the reproducibility of R2*-based LIC estimation remains unknown.

Findings In scan sequences with an initial echo time (TE) ≤ 1.0 ms and a TE spacing ≤ 1.4 ms, the R2*-based LIC quantification at 1.5 T achieved good reproducibility.

Clinical relevance The 1.5-T MRI-based R2* method enables reproducible quantification of the LIC; its reproducibility spares patients from unnecessary trauma and economic burdens while promoting the extensive clinical dissemination of R2*-based LIC quantification methods.

Graphical Abstract