ABSTRACT Purpose: To improve liver iron load assessment by investigating the precision of different approaches of T2* Measurement. Background: Iron overload is a major problem in the treatment of thalassemic patients. Liver iron concentration (LIC) is an important index toward the management of body iron load. The accuracy of iron load estimation may suffer from the methodology of T2* measurement and there is no complete agreement upon the best approach of T2* calculation. Methods: 32 β-thallasemic patients (18 male) with the mean age of 20.0 ± 6.5 years were involved in this study. A multi-echo fast gradient-echo technique on a 1.5 T MRI system was used to measure liver iron overload and the T2* map of liver was reconstructed on a pixel-by-pixel basis. The T2* map and MRI images were utilized to deter- mine accurate location of ROI (region of interest). The mean of T2* were computed from the ROIs. The reproducibility of calculated T2* values in two methods were obtained. Moreover, the mean of the pixel’s T2* was calculated in the entire liver parenchyma of one slice. The T2* value of the entire slice was compared with the ROI approach. Results: In the ROI based method, the CoV for the intra-observer reproducibility was 8.5% and for the inter-observer was 9.78%. In the pixel based method, the CoVs for intra-observer and inter-observer reproducibility were 2.79% and 3.91%. There was an acceptable correlation (r = 0.96) between the T2* values calculated by the ROI and the entire slice. Conclusions: The pixel-based approach is more precise to determine the appropriate placement of the ROI. The assessment of T2* in the entire slice reduces the user-based errors significantly.
Cite this paper
N. Gholizadeh, S. Akhlaghpoor, H. Soltanian-Zadeh, E. Fatemizadeh, M. Alinaghizadeh, A. Akhtari and M. Nourizadeh, "Optimization of Liver Iron Load Assessment by Pixel-Based T2* MRI in Thalassemic Patients," Open Journal of Radiology, Vol. 2 No. 2, 2012, pp. 46-51. doi: 10.4236/ojrad.2012.22008.
 J. M. Alustiza , A. Castiella, M. D. De Juan, J. I. Emparanza, J. Artetxe, et al., “Iron Overload in the Liver Diagnostic and Quantification,” European Journal of Radiology, Vol. 61, No. 3, 2007, pp. 499-506.
 J. C. Wood, C. Enriquez, N. Ghugre, J. M. Tyzka, S. Carson, M. D. Nelson, et al., “MRI R2 and R2* Mapping Accurately Estimates Hepatic Iron Concentration in Transfusion-Dependent Thalassemia and Sickle Cell Disease Patients,” Blood, Vol. 106, No. 4, 2005, 1460-1465.
 T. G. He, P. D. Gatehouse, L. J. Anderson, et al., “Development of a Novel Optimized Breathhold Technique for Myocardial T2 Measurement in Thalassemia,” Journal of Magnetic Resonance Imaging, Vol. 24, No. 3, 2006, pp. 580-585.
 T. G. Maris, O. Papakonstantinou, V. Chatzimanoli, A. Papadakis, et al., “Myocardial and Liver Iron Status Using a Fast T*2 Quantitative MRI (T*2qMRI) Technique,” Magnetic Resonance in Medicine, Vol. 57, No. 4, 2007, pp. 742-753. doi:10.1002/mrm.21204
 E. Angelucci, G. M. Brittenham, C. E. McLaren, M. Ripalti, D. Baronciani, et al., “Hepatic Iron Concentration and Total Body Iron Store in Thalassemia Major,” New England Journal of Medicine, Vol. 343, No. 5, 2000, pp. 327331.
 V. Positano, B. Salani, A. Pepe, M. F. Santarelli, D. De Marchi, A. Ramazzotti, et al., “Improved T2* Assessment in Liver Iron Overload by Magnetic Resonance Imaging,” Magnetic Resonance Imaging, Vol. 27, No. 2, 2009, pp. 188-197. doi:10.1016/j.mri.2008.06.004
 E. Alexopoulou, F. Stripeli, P. Baras, I. Seimenis, et al., “R2 Relaxometry with MRI for the Quantification of Tissue Iron Overload in β-Thalassemic Patients,” Journal of Magnetic Resonance Imaging, Vol. 23, No. 2, 2006, pp. 163-170.
 A. Christoforidis, A. Haritandi, I. Tsitouridis, I. Tsatra, et al., “Correlative Study of Iron Accumulation in Liver, Myocardium, and Pituitary Assessed with MRI in Young Thalassemic Patients,” Journal of Pediatric Hematology/ Oncology, Vol. 28, No. 5, 2006, pp. 311-315.
 M. A Tanner, T. G. He, M. A. Westwood and D. N. Firmin, “Multi-Center Validation of the Transferability of the Magnetic Resonance T2* Technique for the Quantification of Tissue Iron,” Haematologica, Vol. 91, No. 10, 2006, pp. 1388-1391.
 M. I. Argyropoulou and L. Astrakas, “MRI Evaluation of Tissue Iron Burden in Patients with β-Thalassaemia Major,” Pediatric Radiology, Vol. 37, No. 12, 2007, pp. 1191-1200. doi:10.1007/s00247-007-0567-1
 J. C. Wood, M. Otto-Duessel, M. Aguilar, H. Nick, M. D. Nelson, T. D. Coates, et al., “Cardiac Iron Determines Cardiac T2*, T2, and T1 in the Gerbil Model of Iron Cardiomyopathy,” Circulation, Vol. 112, No. 4, 2005, pp. 535-543. doi:10.1161/CIRCULATIONAHA.104.504415
 T. G. St. Pierre, P. R. Clark, W. Chua-Anusorn, A. J. Fleming, G. P. Jeffrey, et al., “Noninvasive Measurement and Imaging of Liver Iron Concentrations Using Proton Magnetic Resonance,” Blood, Vol. 105, No. 2, 2005, pp. 855861. doi:10.1182/blood-2004-01-0177
 L. J. Anderson, S. Holden, B. Davis, E. Prescott, C. C. Charrier, N. H. Bunce, et al., “Cardiovascular T2-Star (T2*) Magnetic Resonance for the Early Diagnosis of Myocardial Iron Overload,” European Heart Journal, Vol. 22, No. , 2001, pp. 2171-2179. doi:10.1053/euhj.2001.2822
 A. Pepe, M. Lombardi, V. Positano, E. Cracolici, M. Capra, et al., “Evaluation of the Efficacy of Oral Deferiprone in β-Thalassemia Major by Multislice Multiecho T2*,” European Journal of Haematology, Vol. 76, No. 3, 2006, pp. 183-192.
 C. Rossi, A. Boss, M. Haap, P. Martirosian, et al., “WholeBody T2* Mapping at 1.5 T,” Magnetic Resonance Imaging, Vol. 27, No. 4, 2009, pp. 489-496.
 H. Soltanian-Zadeh, D. J. Peck, D. O. Hearshen and R. R. Lajiness-O’Neill, “Model-Independent Method for fMRI Analysis,” IEEE Transactions on Medical Imaging, Vol. 23, No. 3, 2004, pp. 285-296.
 R. T. Song, A. R. Cohen and H. K. Song, “Improved Transverse Relaxation Rate Measurement Techniques for the Assessment of Hepatic and Myocardial Iron Content,” Journal of Magnetic Resonance Imaging, Vol. 26, No. 1, 2007, pp. 208-214. doi:10.1002/jmri.20994
 M. Westwood, L. J. Anderson, D. N. Firmin, et al., “A Single Breath-Hold Multiecho T2* Cardiovascular Magnetic Resonance Technique for Diagnosis of Myocardial Iron Overload,” Journal of Magnetic Resonance Imaging, Vol. 18, No. 1, 2003, pp. 33-39.
 S. Mavrogeni, E. Gotsis, V. Ladis, E. Berdousis, et al., “Magnetic Resonance Evaluation of Liver and Myocardial Iron Deposition in Thalassemia Intermedia and βThalassemia Major,” International Journal of Cardiovascular Imaging, Vol. 24, No. 8, 2008, pp. 849-854.
 S. Mavrogeni, E. D. Gotsis, E. Berdousi, V. Ladis, et al., “Myocardial and Hepatic T2* Magnetic Resonance Evaluation in Ex-Thalassemic Patients after Bone-Marrow Transplantation,” International Journal of Cardiovascular Imaging, Vol. 23, No. 6, 2007, pp. 739-745.
 E. Angelucci, P. Muretto, A. Nicolucci, et al., “Effects of Iron Overload and Hepatitis C Virus Positivity in Determining Progression of Liver Fibrosis in Thalassemia Following Bone Marrow Transplantation,” Blood, Vol. 100, No. 1, 2002, pp. 17-21.
 A. W. Olthof, P. E. Sijens, H. G. Kreeftenberg, et al., “Non-Invasive Liver Iron Concentration Measurement by MRI, Comparison of Two Validated Protocols,” European Journal of Radiology, Vol. 71, No. 1, 2009, pp. 116-121.