Utility of real-time prospective motion correction (PROMO) on 3D T1-weighted imaging in automated brain structure measurements.

Keita Watanabe,Shingo Kakeda,Natsuki Igata,Yukunori Korogi,Hidekuni Narimatsu,Dan Rettmann Dan Rettmann,Rieko Watanabe,Osamu Abe,Atsushi Nozaki

doi:10.1038/srep38366

Abstract

PROspective MOtion correction (PROMO) can prevent motion artefacts. The aim of this study was to determine whether brain structure measurements of motion-corrected images with PROMO were reliable and equivalent to conventional images without motion artefacts. The following T1-weighted images were obtained in healthy subjects: (A) resting scans with and without PROMO and (B) two types of motion scans (“side-to-side” and “nodding” motions) with and without PROMO. The total gray matter volumes and cortical thicknesses were significantly decreased in motion scans without PROMO as compared to the resting scans without PROMO (p < 0.05). Conversely, Bland–Altman analysis indicated no bias between motion scans with PROMO, which have good image quality, and resting scans without PROMO. In addition, there was no bias between resting scans with and without PROMO. The use of PROMO facilitated more reliable brain structure measurements in subjects moving during data acquisition.

Highlights

Automated brain structure analysis using three-dimensional T1-weighted imaging (3D-T1WI) with voxel-based morphometry (VBM) and surface-based morphometry has contributed to the identification of morphological abnormalities in dementia and various psychiatric disorders[1,2]
Reuter et al revealed that motion artefacts apparently reduced gray matter (GM) volume and cortical thickness[9], which can lead to false results in automated brain structure measurements
The novelty of the present study lies in the fact that PROspective MOtion correction (PROMO) improved the repeatability of brain structure measurements, even for subjects instructed to remain as still as possible

Summary

Introduction

Automated brain structure analysis using three-dimensional T1-weighted imaging (3D-T1WI) with voxel-based morphometry (VBM) and surface-based morphometry has contributed to the identification of morphological abnormalities in dementia and various psychiatric disorders[1,2]. PROMO utilises three orthogonal 2D spiral navigator (S-NAV) acquisitions along with a flexible image-based tracking method for real-time motion measurement and correction[10]. These navigators, which are interspersed within the T1 recovery time, are used to fix the coordinate system relative to the subject brain position to correct for both in-plane and through-plane movement. PROMO uses non-iterative recursive Kalman filters (EKF), which are well suited for rapid real-time implementation These features facilitate the combination of computation and correction to retrieve real-time position information with motion trajectory data to measure the position of the subject in the upcoming acquisition and to automatically rescan images acquired during intervals with significant head motion[8,10]. The second aim was to assess whether PROMO improves the repeatability of brain structure measurements by correcting for small motions at rest

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Results

Conclusion