title: Statistical Instability of TBSS Analysis Based on DTI Fitting Algorithm.
abstract: Voxel-based DTI analysis is an important approach in the comparison of subject groups by detecting and localizing gray and white matter changes in the brain. One of the principal problems for intersubject comparison is the absence of a "gold standard" processing pipeline. As a result, contradictory results may be obtained from identical data using different data processing pipelines, for example, in the data normalization or smoothing procedures. Tract-based spatial statistics (TBSS) shows potential to overcome this problem by automatic detection of white matter changes and decreasing variation in the performed analysis. However, skeleton projection approaches, such as TBSS, critically depend on the accuracy of the diffusion scalar metric estimations. In this work, we demonstrate that the agreement and reliability of TBSS results depend on the applied DTI data processing algorithm. Statistical tests have been performed using two in vivo measured datasets and compared with different implementations of the least squares algorithm. As a result, we recommend repeating TBSS analysis using different fitting algorithms, in particular, using on iteratively-assessed robust estimators, as accurate and more reliable approach in voxel-based analysis, particularly, for TBSS. Repeating TBSS analysis allows one to detect and localize suspicious regions in white matter which were estimated as the regions with significant difference. Finally, we did not find a favorite fitting algorithm (or class of them) which can be marked as more reliable for group comparison.
authors: Institute of Neuroscience and Medicine-4, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany.
authors: Ivan I
authors: II
authors: Maximov
authors: Institute of Neuroscience and Medicine-4, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany.|Department of Child and Adolescent Psychiatry and Psychotherapy, RWTH Aachen University, 52074, Aachen, Germany.
authors: Heike
authors: H
authors: Thönneßen
authors: Department of Child and Adolescent Psychiatry and Psychotherapy, RWTH Aachen University, 52074, Aachen, Germany.|Institute of Neuroscience and Medicine-3, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany.|JARA-BRAIN-Translational Medicine, RWTH Aachen University, 52074, Aachen, Germany.
authors: Kerstin
authors: K
authors: Konrad
authors: Institute of Neuroscience and Medicine-4, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany.|Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, 52074, Aachen, Germany.
authors: Laura
authors: L
authors: Amort
authors: Institute of Neuroscience and Medicine-4, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany.|Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, 52074, Aachen, Germany.|JARA-BRAIN-Translational Medicine, RWTH Aachen University, 52074, Aachen, Germany.
authors: Irene
authors: I
authors: Neuner
authors: Institute of Neuroscience and Medicine-4, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany.|Department of Neurology, RWTH Aachen University, 52074, Aachen, Germany.|JARA-BRAIN-Translational Medicine, RWTH Aachen University, 52074, Aachen, Germany.
authors: N Jon
authors: NJ
authors: Shah
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D001921:Brain / Q000000981:diagnostic imaging*; D001931:Brain Mapping / Q000379:methods*; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D066127:White Matter / Q000000981:diagnostic imaging*; D055815:Young Adult
keywords: Diffusion tensor imaging; TBSS result variability; modified least trimmed squares; robust diffusion imaging framework; robust tensor estimation; tract-based spatial statistics