Purpose: To compare three types of MRI liver iron content (LIC) measurement performed in daily clinical routine in a single center over a 6-year period.
Methods: Patients undergoing LIC MRI-scans (1.5T) at our center between January 1, 2008 and December 31, 2013 were retrospectively included. LIC was measured routinely with signal intensity ratio (SIR) and MR-relaxometry (R 2 and R 2*) methods. Three observers placed regions-of-interest. The success rate was the number of correctly acquired scans over the total number of scans. Interobserver agreement was assessed with intraclass correlation coefficients (ICC) and Bland-Altman analysis, correlations between LICSIR, R 2, R 2*, and serum values with Spearman's rank correlation coefficient. Diagnostic accuracies of LICSIR, R 2 and serum transferrin, transferrin-saturation, and ferritin compared to increased R 2* (≥44 Hz) as indicator of iron overload were assessed using ROC-analysis.
Results: LIC MRI-scans were performed in 114 subjects. SIR, R 2, and R 2* data were successfully acquired in 102/114 (89%), 71/114 (62%), and 112/114 (98%) measurements, with the lowest success rate for R 2. The ICCs of SIR, R 2, and R 2* did not differ at 0.998, 0.997, and 0.999. R 2 and serum ferritin had the highest diagnostic accuracies to detect elevated R 2* as mark of iron overload.
Conclusions: SIR and R 2* are preferable over R 2 in terms of success rates. R 2*'s shorter acquisition time and wide range of measurable LIC values favor R 2* over SIR for MRI-based LIC measurement.
Keywords: Biomarker; Blood transfusion; Hemochromatosis; Iron overload; Magnetic resonance imaging; Relaxometry.