Novel equation to determine liver iron overload using mDixon Quant

Congress:

ECR 2018

Poster Number:

C-2881

Type:

Scientific Exhibit

Keywords:

Diagnostic procedure, MR, Liver, Metabolic disorders

Authors:

A. Ugarte¹, J. M. Alústiza¹, E. salvador², J. I. Emparanza¹, J. Sanchez³; ¹San Sebastian/ES, ²San Sebastián/ES, ³Madrid/ES

DOI:

10.1594/ecr2018/C-2881

DOI-Link:

https://dx.doi.org/10.1594/ecr2018/C-2881

$Fig. 1: The image shows an example of the maps obtained with mDixon Quant: fat, fat fraction, water and T2* maps.$

Fig. 1: The image shows an example of the maps obtained with mDixon Quant: fat, fat...

Fig. 2: The graph shows the correlation between T2* values and LIC.

Fig. 3: The graph shows correlation between T2* values and LIC, excluding those cases...

Aims and objectives

Multi-point multi-peak DIXON techniques have shown high reproducibility to estimate proton density fat fraction among different magnetic fields and different imaging platforms1. These methods take into account R2* exponential decay to prevent R2* relaxation effects on fat fraction estimation2,3. The resulting R2* maps can be used to assess iron overload in combination with fat fraction infiltration in a single acquisition. Our purpose is to assess the correlation between T2* maps obtained with mDixon Quant and liver iron concentration (LIC) using as gold standard a validated...

Methods and materials

The research project was approved by the Institutional Research Board and all participant signed informed consent. Seventy-two patients with different degrees of iron overload were enrolled in the study. All acquisitions were acquired in a 1.5T Ingenia system (Philips Heathtech, Best, The Netherlands). The magnetic resonance protocol includedmDIXON Quant acquisition with six echos (TR/Initial TE/∆TE/flip angle = 6.5ms\1.16ms\0.8ms\5o) and it was used to obtain water, fat, fat fraction and T2* maps. R2* values were obtained in 3 regions of interest (ROIs) placed in right liver...

Results

Iron concentration in the cohort ranged from 5 μmol Fe/g to 477 μmol Fe/g (78.63±76.30 μmol Fe/g). MDixon Quant R2* map positively correlates with the liver iron concentration calculated by FerriScan, resulting in a novel equation to quantify liver iron concentration: LIC (µmol/gr)= e^(6.27-1.20(LnDixonT2*)) (r20.84). A simpler linear model, excluding those with very high LIC (n=2), was obtained: LIC(µmol/gr)= 2.27R2*-0.38 (r2=0.89). This model saturates above 250 µmol/gr.

Conclusion

R2* values obtained from mDIXON Quant technique show good correlation with Iron overloa, although R2* values present some saturation for iron overloads higher than 250 μmol Fe/g.

Personal information

References

1. Serai SD, Dillman JR, Trout AT. Proton Density Fat Fraction Measurements at 1.5- and 3-T Hepatic MR Imaging: Same-Day Agreement among Readers and across Two Imager Manufacturers. Radiology. 2017 Jul;284(1):244-254. 2. Yu H, Shimakawa A, McKenzie CA, Brodsky E, Brittain JH, Reeder SB. Multiecho water-fat separation and simultaneous R2* estimation with multifrequency fat spectrum modeling. Magn Reson Med. 2008 Nov;60(5):1122-34. 3. Eggers H1, Brendel B, Duijndam A, Herigault G. Dual-echo Dixon imaging with flexible choice of echo times. Magn Reson Med. 2011 Jan;65(1):96-107. 4.Pierre,...