Whole brain myelin mapping using T1- and T2-weighted MR imaging data.

Journal article

Despite recent advancements in MR imaging, non-invasive mapping of myelin in the brain still remains an open issue. Here we attempted to provide a potential solution. Specifically, we developed a processing workflow based on T1-w and T2-w MR data to generate an optimized myelin enhanced contrast image. The workflow allows whole brain mapping using the T1-w/T2-w technique, which was originally introduced as a non-invasive method for assessing cortical myelin content. The hallmark of our approach is a retrospective calibration algorithm, applied to bias-corrected T1-w and T2-w images, that relies on image intensities outside the brain. This permits standardizing the intensity histogram of the ratio image, thereby allowing for across-subject statistical analyses. Quantitative comparisons of image histograms within and across different datasets confirmed the effectiveness of our normalization procedure. Not only did the calibrated T1-w/T2-w images exhibit a comparable intensity range, but also the shape of the intensity histograms was largely corresponding. We also assessed the reliability and specificity of the ratio image compared to other MR-based techniques, such as magnetization transfer ratio (MTR), fractional anisotropy (FA), and fluid-attenuated inversion recovery (FLAIR). With respect to these other techniques, T1-w/T2-w had consistently high values, as well as low inter-subject variability, in brain structures where myelin is most abundant. Overall, our results suggested that the T1-w/T2-w technique may be a valid tool supporting the non-invasive mapping of myelin in the brain. Therefore, it might find important applications in the study of brain development, aging and disease.

Authors: Ganzetti, M; Wenderoth, N; Mantini, D

• Publication status: Published
• Publisher: Frontiers Research Foundation
• Journal: Frontiers in human neuroscience
• Volume: 8
• Issue: SEP
• Pages: 671
• Publication date: 2014-01-01
• DOI: 10.3389/fnhum.2014.00671
• EISSN: 1662-5161
• ISSN: 1662-5161
• Language: English
• Keywords: brain mapping; myelin mapping; brain integrity assessment; myelin enhanced contrast; magnetic resonance imaging