Noninvasive liver iron quantification by MRI using refocused gradient-echo (bSSFP): preliminary results

Abstract

Purpose To evaluate the feasibility of using a balanced steady-state free precession sequence (bSSFP) to determine liver iron content (LIC). Method Thirty-five consecutive patients with liver iron overload were examined with bSSFP. Signal intensity ratios of liver parenchyma to paraspinal muscles were retrospectively correlated with LIC values obtained by FerriScan, which was used as the reference method. Combinations of bSSFP protocols were also evaluated. The best combination was utilized to calculate LIC from bSSFP data. The sensitivity and specificity for the therapeutically relevant LIC threshold of 80 µmol/g (4.5 mg/g) were determined. Results LIC values ranged from 24 to 756 µmol/g. The best SIR-to-LIC correlation of a single protocol was obtained with a 3.5-ms repetition time (TR) and 17° excitation flip angle (FA). A combination of protocols with TRs of 3.5, 5, and 6.5 ms, each at 17° FA, yielded a superior correlation. LIC values calculated using this combination resulted in a sensitivity/specificity of 0.91/0.85. Conclusion bSSFP is basically suitable to determine LIC. Its advantages are high SNR efficiency and the ability to acquire the entire liver in a breath hold without acceleration techniques. Key Points:  Citation Format