Characterization and correction of the effects of hepatic iron on T 1ρ relaxation in the liver at 3.0T
Yurui Qian, Jian Hou, Baiyan Jiang,Vincent Wai-Sun Wong, Jack Lee, Queenie Chan, Yixiang Wang, Winnie Chiu-Wing Chu, Weitian Chen
Abstract
Purpose
Quantitative T1ρ imaging is an emerging technique to assess the biochemical properties of tissues. In this paper, we report our observation that liver iron content (LIC) affects T1ρ quantification of the liver at 3.0T field strength and develop a method to correct the effect of LIC.
Theory and Methods
On-resonance R1ρ (1/T1ρ) is mainly affected by the intrinsic R2 (1/T2), which is influenced by LIC. As on-resonance R1ρ is closely related to the Carr–Purcell–Meiboom–Gill (CPMG) R2, and because the calibration between CPMG R2 and LIC has been reported at 1.5T, a correction method was proposed to correct the R2 contribution to the R1ρ. The correction coefficient was obtained from the calibration results and related transformed factors. To compensate for the difference between CPMG R2 and R1ρ, a scaling factor was determined using the values of CPMG R2 and R1ρ, obtained simultaneously from a single breath-hold from volunteers. The livers of 110 subjects were scanned to validate the correction method.
Results
LIC was significantly correlated with R1ρ in the liver. However, when the proposed correction method was applied to R1ρ, LIC and the iron-corrected R1ρ were not significantly correlated.
Conclusion
LIC can affect T1ρ in the liver. We developed an iron-correction method for the quantification of T1ρ in the liver at 3.0T.