Ultra-Short Echo Phase-Based R2 Mapping for Liver Iron Overload

Motivation: Conventional R2 mapping techniques for detection of liver iron overload suffers from long scan times and low signal-to-noise ratio (SNR), especially in cases of severe iron overload where signal decays rapidly. Goal(s): To develop an ultra-short echo phase-based (UTE-PB) R2 mapping that improves the dynamic range and accuracy of R2 measurements. Approach: We incorporated UTE imaging into two-dimensional PB imaging. A four-pass acquisition protocol was used to obtain images that encode R2 (=1/T2) information into the signal phase. Phantom and in vivo studies were included. Results: UTE-PB R2 mapping demonstrated improved SNR and uniformity compared to conventional methods but moderately overestimated R2 values. Impact: UTE-PB R2 mapping enhances the quantification of severe iron overload with improved SNR and dynamic range, potentially improving the diagnosis of patients with iron overload. Further research is needed to optimize and validate PB R2 mapping for high R2 conditions.