Correction of Inter-Scan Motion Artifacts in Quantitative R1 Mapping by Accounting for Receive Coil Sensitivity Effects

Purpose: Inter-scan motion causes differential receive field modulation between scans, leading to errors when they are combined to quantify MRI parameters. We present a robust and efficient method that accounts for inter-scan motion by removing this modulation before parameter quantification. Theory and Methods: Five participants moved between two high-resolution structural scans acquired with different flip angles. Before each high-resolution scan, the effective relative sensitivity of the receive head coil was estimated by combining two rapid low-resolution scans acquired receiving on each of the body and head coils. All data were co-registered and sensitivity variations were removed from the high-resolution scans by division with the effective relative sensitivity. R1 maps with and without this correction were calculated and compared against reference maps unaffected by inter-scan motion. Results: Even after coregistration, inter-scan motion significantly biased the R1 maps, leading to spurious variation in R1 in brain tissue and deviations with respect to a no-motion reference. The proposed correction scheme reduced the error to within the typical scan-rescan error observed in datasets unaffected by motion. Conclusion: Inter-scan motion negatively impacts the accuracy and precision of R1 mapping. We present a validated correction method that accounts for position-specific receive field modulation. (C) 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.