Prospective Head Motion Correction in T1‐ and T2‐Weighted Long Echo Train Sequences Using Servo Navigation
Matthias Serger, Malte Riedel, Rüdiger Stirnberg, Thomas Ulrich, Nicolas Boulant, Klaas P. Pruessmann, Tony Stöcker, Philipp EhsesABSTRACT
Purpose
To integrate MR‐based servo navigation in MPRAGE and 3D‐TSE sequences and demonstrate its potential for prospective head motion correction in structural imaging.
Methods
Repeated modules of servo navigators were inserted before each preparation pulse of MPRAGE and 3D‐TSE sequences (before‐prep) for rapid convergence of motion parameter estimation. Additionally, reference navigators were distributed along the imaging echo train to test a within‐echo train correction (within‐ET) with contrast‐matched models, enabling more frequent geometry updates. The methods were evaluated in instructed motion experiments and in high‐resolution scans at 7T.
Results
Artifacts caused by instructed abrupt motion were clearly reduced in scans with servo navigation for both sequences using the before‐prep correction. Residual artifacts of rapid in‐train motion were further mitigated by the within‐ET correction in MPRAGE. In high‐resolution scans with minimal motion, servo navigation preserved fine anatomical details, while it improved image quality under involuntary motion in long acquisitions.
Conclusion
Servo navigation provides accurate real‐time head motion correction for structural brain imaging.