Premium
Population‐Level Correction of Systematic Motion Artifacts in fMRI in Patients with Ischemic Stroke
Author(s) -
Aranyi Csaba,
Opposits Gábor,
Nagy Marianna,
Berényi Ervin,
Vér Csilla,
Csiba László,
Katona Péter,
Spisák Tamás,
Emri Miklós
Publication year - 2016
Publication title -
journal of neuroimaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.822
H-Index - 64
eISSN - 1552-6569
pISSN - 1051-2284
DOI - 10.1111/jon.12408
Subject(s) - medicine , stroke (engine) , ischemic stroke , population , physical medicine and rehabilitation , cardiology , ischemia , mechanical engineering , environmental health , engineering
BACKGROUND The aim of this study was to reveal potential sources of systematic motion artifacts in stroke functional magnetic resonance imaging (fMRI) focusing on those causing stimulus‐correlated motion on the individual‐level and separate the motion effect on the fMRI signal changing from the activation‐induced alteration at population level. METHODS Eleven ischemic stroke patients were examined by fMRI. The fMRI paradigm was based on passive ankle movement on both the healthy and the paretic leg's side. Three individual‐level motion correction strategies were compared and we introduced five measures to characterize each subjects' in‐scanner relative head movement. After analyzing the correlation of motion parameters and the subjects’ physiological scale scores, we selected a parameter to model the motion‐related artifacts in the second‐level analysis. RESULTS At first (individual) level analysis, the noise‐component correction‐based CompCor method provided the highest −log10( p ) value of cluster‐level occurrence probability at 12.4/13.6 for healthy and paretic side stimulus, respectively, with a maximal z ‐value of 15/16.3. Including the motion parameter at second (group) level resulted in lower cluster occurrence values at 10.9/5.55 while retaining the maximal z ‐value. CONCLUSIONS We proposed a postprocessing pipeline for ischemic stroke fMRI data that combine the CompCor correction at first level with the modeling of motion effect at second‐level analysis by a parameter obtained from fMRI data. Our solution is applicable for any fMRI‐based stroke rehabilitation study since it does not require any MRI‐compatible motion capture system and is based on commonly used methods.