Prospective Motion Correction For Brain Mri Using An External Tracking System

BACKGROUND AND PURPOSE A wide range of strategies have been developed to mitigate motion, as a major source of image quality degradation in clinical MRI. We aimed to assess the efficiency of a commercially available prospective motion correction (PMC) system in reducing motion in acquiring high-resolution 3D magnetization-prepared rapid gradient-echo (MPRAGE).METHODS A total of 100 patients who referred for brain MRI studies were prospectively imaged using a 3.0T scanner. 3D MPRAGE acquisition was obtained with and without application of PMC. The motion tracking system (KinetiCor Inc.) consisted of a quad camera apparatus, which tracks a specific marker on patient's head by evaluating the marker's optical pattern. The patient's head motion in 6 degrees of freedom throughout the acquisition was then incorporated into the MRI sequence, updating the image acquisition in real time based on the most recent head pose data. MPRAGE images with and without motion correction were assessed independently by two board-certified neuroradiologists using a 5-point Likert scale. Statistical analysis included kappa and Wilcoxon Rank-Sum tests.RESULTS Observers 1 and 2 identified nondiagnostic studies in 17.2% and 20.7% of patients (K = .78, 95% CI .70-.86) without motion correction and in 5.7% and 8% of the studies with motion correction (K = .84, 95% CI .76-.92). The number of nondiagnostic studies was significantly (P = .001) reduced from 19.5% to 5.7% after motion correction in consensus read analysis.CONCLUSION The described motion tracking system can be used effectively in clinical practice reducing motion artifact and improving image quality of 3D MPRAGE sequence.