Lorenzo Bacigalupo1, Francesco Paparo2, Daniele Zefiro3, Carlo Maria Viberti4, Luca Cevasco2, Barbara Gianesin4, Valeria Maria Pinto5, Gian Andrea Rollandi2, John C Wood6, Gian Luca Forni5. 1. Radiology Unit, Department of Diagnostic Imaging, E.O. Ospedali Galliera, Mura delle Cappuccine 14, 16128, Genoa, Italy. lorenzo.bacigalupo@galliera.it. 2. Radiology Unit, Department of Diagnostic Imaging, E.O. Ospedali Galliera, Mura delle Cappuccine 14, 16128, Genoa, Italy. 3. Department of Medical Physics, ASL n.5 "Spezzino", Via XXIV Maggio 139, 19124, La Spezia, Italy. 4. Medical Physics Unit, E.O. Ospedali Galliera, Mura delle Cappuccine 14, 16128, Genoa, Italy. 5. Microcitemia and Hereditary Anaemias Unit, E.O. Ospedali Galliera, Mura delle Cappuccine 14, 16128, Genoa, Italy. 6. Department of Radiology, Children's Hospital Los Angeles, Los Angeles, CA, USA.
Abstract
PURPOSE: In magnetic resonance imaging (MRI) relaxometry, various software programs are available to perform R2* measurements and to estimate the liver iron concentration (LIC). The main objective of our study was to compare R2* LIC values, obtained with three different software programs based on specific decay models and calibration curves, with LIC estimates provided by R2-relaxometry (FerriScan). METHODS: This retrospective study included 15 patients with 15 baseline MRIs and 34 serial examinations. R2* LIC estimates were calculated using the FuncTool, CMRtools/Thalassemia Tools and Quanta Hematology programs. Longitudinal LIC changes (ΔLIC) were calculated using the subset of 34 serial MRIs. RESULTS: After Bland-Altman analysis on baseline data, Quanta Hematology, which employs the monoexponential-plus-constant fit, produced the lowest mean difference [0.01 ± 0.14 log(mg/gdw)] with the closest limits of agreement. In the longitudinal setting, Quanta Hematology again gave the lowest mean difference between R2 and R2* LIC (0.1 ± 2.6 mg/gdw). Using FerriScan as reference, the value of concordant directional ΔLIC changes was the same for all programs (27/34, 85.7 %). CONCLUSIONS: R2* LICs are higher than R2 LICs at iron levels <7 mg/gdw, while R2 LIC averages higher than R2* LIC with increasing iron load. The monoexponential-plus-constant model provided the best agreement with R2 LIC estimates.
PURPOSE: In magnetic resonance imaging (MRI) relaxometry, various software programs are available to perform R2* measurements and to estimate the liver iron concentration (LIC). The main objective of our study was to compare R2* LIC values, obtained with three different software programs based on specific decay models and calibration curves, with LIC estimates provided by R2-relaxometry (FerriScan). METHODS: This retrospective study included 15 patients with 15 baseline MRIs and 34 serial examinations. R2* LIC estimates were calculated using the FuncTool, CMRtools/Thalassemia Tools and Quanta Hematology programs. Longitudinal LIC changes (ΔLIC) were calculated using the subset of 34 serial MRIs. RESULTS: After Bland-Altman analysis on baseline data, Quanta Hematology, which employs the monoexponential-plus-constant fit, produced the lowest mean difference [0.01 ± 0.14 log(mg/gdw)] with the closest limits of agreement. In the longitudinal setting, Quanta Hematology again gave the lowest mean difference between R2 and R2* LIC (0.1 ± 2.6 mg/gdw). Using FerriScan as reference, the value of concordant directional ΔLIC changes was the same for all programs (27/34, 85.7 %). CONCLUSIONS: R2* LICs are higher than R2 LICs at iron levels <7 mg/gdw, while R2 LIC averages higher than R2* LIC with increasing iron load. The monoexponential-plus-constant model provided the best agreement with R2 LIC estimates.
Entities:
Keywords:
Biopsy; Liver iron concentration (LIC); Liver iron overload; Magnetic resonance imaging; β-Thalassemia
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