title: Quantification of accuracy and precision of multi-center DTI measurements: a diffusion phantom and human brain study.
abstract: The inter-site and intra-site variability of system performance of MRI scanners (due to site-dependent and time-variant variations) can have significant adverse effects on the integration of multi-center DTI data. Measurement errors in accuracy and precision of each acquisition determine both the inter-site and intra-site variability. In this study, multiple scans of an identical isotropic diffusion phantom and of the brain of a traveling human volunteer were acquired at MRI scanners from the same vendor and with similar configurations at three sites. We assessed the feasibility of multi-center DTI studies by direct quantification of accuracy and precision of each dataset. Accuracy was quantified via comparison to carefully constructed gold standard datasets while precision (the within-scan variability) was estimated by wild bootstrap analysis. The results from both the phantom and human data suggest that the inter-site variation in system performance, although relatively small among scanners of the same vendor, significantly affects DTI measurement accuracy and precision and therefore the effectiveness for the integration of multi-center DTI measurements. Our results also highlight the value of a DTI-specific phantom in identifying and quantifying measurement errors due to site-dependent variations in the system performance, and its usefulness for quality assurance/quality control in multi-center DTI studies. In addition, we observed that the within-scan variability of each data acquisition, as assessed by wild bootstrap analysis, is of the same magnitude as the inter-site and intra-site variability. We propose that by weighing datasets based on their variability, as evaluated by wild bootstrap analysis, one can improve the quality of the dataset. This approach will provide a more effective integration of datasets from multi-center DTI studies.
authors.affiliation: Department of Imaging Sciences, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642-8648, USA.
authors.forename: Tong
authors.initials: T
authors.lastname: Zhu
authors.forename: Rui
authors.initials: R
authors.lastname: Hu
authors.forename: Xing
authors.initials: X
authors.lastname: Qiu
authors.forename: Michael
authors.initials: M
authors.lastname: Taylor
authors.forename: Yuen
authors.initials: Y
authors.lastname: Tso
authors.forename: Constantin
authors.initials: C
authors.lastname: Yiannoutsos
authors.forename: Bradford
authors.initials: B
authors.lastname: Navia
authors.forename: Susumu
authors.initials: S
authors.lastname: Mori
authors.forename: Sven
authors.initials: S
authors.lastname: Ekholm
authors.forename: Giovanni
authors.initials: G
authors.lastname: Schifitto
authors.forename: Jianhui
authors.initials: J
authors.lastname: Zhong
mesh_terms: D001921:Brain / Q000033:anatomy & histology*; D001931:Brain Mapping / Q000379:methods; D003627:Data Interpretation, Statistical; D016208:Databases, Factual; D056324:Diffusion Tensor Imaging / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015337:Multicenter Studies as Topic; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D055815:Young Adult