title: Comparison between different software programs and post-processing techniques for the MRI quantification of liver iron concentration in thalassemia patients.
abstract: OBJECTIVE
  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.
authors.affiliation: Radiology Unit, Department of Diagnostic Imaging, E.O. Ospedali Galliera, Mura delle Cappuccine 14, 16128, Genoa, Italy. lorenzo.bacigalupo@galliera.it.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Bacigalupo
authors.affiliation: Radiology Unit, Department of Diagnostic Imaging, E.O. Ospedali Galliera, Mura delle Cappuccine 14, 16128, Genoa, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Paparo
authors.affiliation: Department of Medical Physics, ASL n.5 "Spezzino", Via XXIV Maggio 139, 19124, La Spezia, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Zefiro
authors.affiliation: Medical Physics Unit, E.O. Ospedali Galliera, Mura delle Cappuccine 14, 16128, Genoa, Italy.
authors.forename: Carlo Maria
authors.initials: CM
authors.lastname: Viberti
authors.affiliation: Radiology Unit, Department of Diagnostic Imaging, E.O. Ospedali Galliera, Mura delle Cappuccine 14, 16128, Genoa, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Cevasco
authors.affiliation: Medical Physics Unit, E.O. Ospedali Galliera, Mura delle Cappuccine 14, 16128, Genoa, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Gianesin
authors.affiliation: Microcitemia and Hereditary Anaemias Unit, E.O. Ospedali Galliera, Mura delle Cappuccine 14, 16128, Genoa, Italy.
authors.forename: Valeria Maria
authors.initials: VM
authors.lastname: Pinto
authors.affiliation: Radiology Unit, Department of Diagnostic Imaging, E.O. Ospedali Galliera, Mura delle Cappuccine 14, 16128, Genoa, Italy.
authors.forename: Gian Andrea
authors.initials: GA
authors.lastname: Rollandi
authors.affiliation: Department of Radiology, Children's Hospital Los Angeles, Los Angeles, CA, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Wood
authors.affiliation: Microcitemia and Hereditary Anaemias Unit, E.O. Ospedali Galliera, Mura delle Cappuccine 14, 16128, Genoa, Italy.
authors.forename: Gian Luca
authors.initials: GL
authors.lastname: Forni
mesh_terms: D000293:Adolescent; D000328:Adult; D001706:Biopsy; D002648:Child; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007501:Iron / Q000032:analysis*; D019190:Iron Overload / Q000000981:diagnostic imaging*; D008099:Liver / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012984:Software; D013789:Thalassemia / Q000000981:diagnostic imaging*
chemical_list: D007501:Iron
keywords: Biopsy; Liver iron concentration (LIC); Liver iron overload; Magnetic resonance imaging; β-Thalassemia