Non-invasive measurement of liver iron concentration using 3-Tesla magnetic resonance imaging: validation against biopsy
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To evaluate the performance and limitations of the R2* and signal intensity ratio (SIR) methods for quantifying liver iron concentration (LIC) at 3 T.
A total of 105 patients who underwent a liver biopsy with biochemical LIC (LICb) were included prospectively. All patients underwent a 3-T MRI scan with a breath-hold multiple-echo gradient-echo sequence (mGRE). LIC calculated by 3-T SIR algorithm (LICSIR) and by R2* (LICR2*) were correlated with LICb. Sensitivity and specificity were calculated. The comparison of methods was analysed for successive classes.
LICb was strongly correlated with R2* (r = 0.95, p < 0.001) and LICSIR (r = 0.92, p < 0.001). In comparison to LICb, LICR2* and LICSIR detect liver iron overload with a sensitivity/specificity of 0.96/0.93 and 0.92/0.95, respectively, and a bias ± SD of 7.6 ± 73.4 and 14.8 ± 37.6 μmol/g, respectively. LICR2* presented the lowest differences for patients with LICb values under 130 μmol/g. Above this value, LICSIR has the lowest differences.
At 3 T, R2* provides precise LIC quantification for lower overload but the SIR method is recommended to overcome R2* limitations in higher overload. Our software, available at www.mrquantif.org, uses both methods jointly and selects the best one.
• Liver iron can be accurately quantified by MRI at 3 T
• At 3 T, R2* provides precise quantification of slight liver iron overload
• At 3 T, SIR method is recommended in case of high iron overload
• Slight liver iron overload present in metabolic syndrome can be depicted
• Treatment can be monitored with great confidence
KeywordsIron Liver Magnetic resonance imaging Haemosiderosis Haemochromatosis
area under the curve
body mass index
dysmetabolic iron overload syndrome
liver iron concentration
LIC assessed by biopsy using biochemical analysis
LIC calculated by T2* conversion
LIC calculated by SIR method
multiple-echo gradient-echo sequence
magnetic resonance imaging
signal intensity ratio
We received support from the national clinical research program for public hospitals of France. Thanks to Tracey Westcott for the language help. Thanks to all the MRI team of University Hospital of Rennes.
Compliance with ethical standards
The scientific guarantor of this publication is Prof Yves Gandon
Conflict of interest
The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article.
Statistics and biometry
One of the authors (MJ) is a senior biostatistician and has significant statistical expertise.
Written informed consent was obtained from all subjects (patients) in this study.
The study protocol (Clinical trial NCT00401336) was approved by the local institutional review board (ref. 05/17-544).
Study subjects or cohorts overlap
This series of patients have been previously used to define a liver-to-muscle signal intensity ratio (SIR) algorithm from five different monoecho sequences. Here we report the R2* results calculated from a multiecho sequence. We also calculated SIR results from this unique sequence using the previously reported algorithm based on monoecho sequences.
• diagnostic or prognostic study
• performed at one institution
- 24.Krafft AJ, Loeffler RB, Song R et al (2017) Quantitative ultrashort echo time imaging for assessment of massive iron overload at 1.5 and 3 Tesla. Magn Reson Med. https://doi.org/10.1002/mrm.26592