Myelin quantification with MRI: A systematic review of accuracy and reproducibility
Chris W.J. van der Weijden,
David Vállez García,
Ronald J.H. Borra,
Patrick Thurner,
Jan F. Meilof,
Peter-Jan van Laar,
Rudi A.J.O. Dierckx,
Ingomar W. Gutmann,
Erik F.J. de Vries
Affiliations
Chris W.J. van der Weijden
Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands
David Vállez García
Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands; Department of Radiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands
Ronald J.H. Borra
Department of Radiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands
Patrick Thurner
Universitätsklinik für Radiologie und Nuklearmedizin, Medizinische Universität Wien, Währinger Gürtel 18-20, 1090 Wien, Austria
Jan F. Meilof
Multiple Sclerosis Center Noord Nederland, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands
Peter-Jan van Laar
Department of Radiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands; Department of Radiology, Zorggroep Twente, Zilvermeeuw 1, 7609 PP Almelo, the Netherlands
Rudi A.J.O. Dierckx
Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands
Ingomar W. Gutmann
Physics of Functional Material, Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria
Erik F.J. de Vries
Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ Groningen, the Netherlands; Corresponding author.
Objectives: Currently, multiple sclerosis is treated with anti-inflammatory therapies, but these treatments lack efficacy in progressive disease. New treatment strategies aim to repair myelin damage and efficacy evaluation of such new therapies would benefit from validated myelin imaging techniques. Several MRI methods for quantification of myelin density are available now. This systematic review aims to analyse the performance of these MRI methods. Methods: Studies comparing myelin quantification by MRI with histology, the current gold standard, or assessing reproducibility were retrieved from PubMed/MEDLINE and Embase (until December 2019). Included studies assessed both myelin histology and MRI quantitatively. Correlation or variance measurements were extracted from the studies. Non-parametric tests were used to analyse differences in study methodologies. Results: The search yielded 1348 unique articles. Twenty-two animal studies and 13 human studies correlated myelin MRI with histology. Eighteen clinical studies analysed the reproducibility. Overall bias risk was low or unclear. All MRI methods performed comparably, with a mean correlation between MRI and histology of R2=0.54 (SD=0.30) for animal studies, and R2=0.54 (SD=0.18) for human studies. Reproducibility for the MRI methods was good (ICC=0.75–0.93, R2=0.90–0.98, COV=1.3–27%), except for MTR (ICC=0.05–0.51). Conclusions: Overall, MRI-based myelin imaging methods show a fairly good correlation with histology and a good reproducibility. However, the amount of validation data is too limited and the variability in performance between studies is too large to select the optimal MRI method for myelin quantification yet.
