1.5-T MR relaxometry in quantifying splenic and pancreatic iron: retrospective comparison of a commercial 3D-Dixon sequence and an established 2D multi-gradient echo sequence

Objectives To compare the quantitative measurement of splenic and pancreatic iron content using a commercial 3D-Dixon sequence (qDixon) versus an established fat-saturated R2* relaxometry method (ME-GRE). Methods We analyzed splenic and pancreatic iron levels in 143 MR examinations (1.5 T) using the qDixon and a ME-GRE sequence (108 patients: 65 males, 43 females, mean age 61.31 years). Splenic and pancreatic R2* values were compared between both methods using Bland–Altman plots, concordance correlation coefficients (CCC), and linear regression analyses. Iron overload (R2* > 50 1/s) was defined for both organs and compared using contingency tables, overall agreement, and Gwet’s AC1 coefficient. Results Of all analyzable examinations, the median splenic R2* using the qDixon sequence was 25.75 1/s (range: 5.6–433) and for the ME-GRE sequence 35.35 1/s (range: 10.9–400.8) respectively. Concerning the pancreas, a median R2* of 29.93 1/s (range: 14–111.45) for the qDixon and 31.25 1/s (range: 14–97) for the ME-GRE sequence was found. Bland–Altman analysis showed a mean R2* difference of 2.12 1/s with a CCC of 0.934 for the spleen and of 0.29 1/s with a CCC of 0.714 for the pancreas. Linear regression for the spleen/pancreas resulted in a correlation coefficient of 0.94 ( p