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Reproducibility of liver iron concentration measured by R2* method based on 1.5-T MRI: a meta-analysis
Sue Cao1, Jie Zhang1, Chenyu Dong1
1Department of Radiology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
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.
Insights
The 1.5-T MRI R2* method reliably measures liver iron concentration (LIC) across various scanners and parameters. This reproducible technique avoids patient trauma and reduces costs, promoting wider clinical use.
Area of Science:
- Radiology
- Medical Imaging
- Biophysics
Background:
- Liver iron concentration (LIC) is crucial for managing iron overload disorders.
- Magnetic Resonance Imaging (MRI) R2* quantification is a non-invasive method for assessing LIC.
- Reproducibility of the 1.5-Tesla (T) MRI R2* method across different settings is essential for clinical adoption.
Purpose of the Study:
- To evaluate the reproducibility of the 1.5-T MRI-based R2* method for measuring LIC.
- To assess the impact of varying MRI scanners, scan parameters, and postprocessing techniques on R2* measurements.
- To determine the reliability of R2*-based LIC quantification in diverse clinical scenarios.
Main Methods:
- A systematic literature search was conducted across major databases (PubMed, Embase, Medline, Cochrane Library, Web of Science).
- Data from 21 studies including 1147 participants were analyzed for R2* measurement reproducibility.
- Statistical analysis assessed variations in R2* values attributed to scanner equipment, scan parameters, and postprocessing techniques, controlling for LIC effects.
Main Results:
- Analysis of 21 studies (1147 participants) demonstrated the reproducibility of the 1.5-T MRI R2* method.
- Studies using an initial echo time (TE) ≤ 1.0 ms and TE spacing ≤ 1.4 ms showed no significant differences in R2* values (p > 0.05).
- A calibration curve was established: LIC (mg/g) = 0.042 + 2.85 × 10⁻² R2* (s⁻¹) (R² = 0.79).
Conclusions:
- The 1.5-T MRI-based R2* method is a reproducible technique for estimating liver iron concentration.
- The method's reproducibility is maintained across different MRI scanners, scan parameters, and postprocessing techniques.
- This non-invasive approach offers clinical relevance by reducing patient burden and promoting wider use of R2*-based LIC quantification.
