Super-resolution track-density imaging studies of mouse brain: Comparison to histology

• Published in: NeuroImage (Orlando, Fla.) Vol. 59; no. 1; pp. 286 - 296
• Main Authors: Calamante, Fernando, Tournier, Jacques-Donald, Kurniawan, Nyoman D., Yang, Zhengyi, Gyengesi, Erika, Galloway, Graham J., Reutens, David C., Connelly, Alan
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 02.01.2012; Elsevier Limited
• Subjects: Animals; Brain; Brain - anatomy & histology; Brain Mapping - methods; Brain research; Diffusion Magnetic Resonance Imaging; Diffusion MRI; Histology; Image Processing, Computer-Assisted - methods; Immunohistochemistry; Magnetic resonance imaging; Mice; Mouse brain; Neural Pathways - anatomy & histology; Studies; Super-resolution; Validation; Mouse brain; fmi; lo; gcc; iFOD2; acp; FOD; Hb; ic; ec; ml; Validation; IMD; MS; mt; CPu; RGB; str; opt; δ; Diffusion MRI; FA; LMol; fi; eml; ns; lmax; fr; 2D; stTDI; CSD; TDI; sm; dhc; cc; st; Super-resolution; DEC; cg; f; mfb; Histology; cp; tc; Br; 3D; TE; PB; Magnetic resonance imaging; pf; aca; TR
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2011.07.014

The recently proposed track-density imaging (TDI) technique was introduced as a means to achieve super-resolution using diffusion MRI. This technique is able to increase the spatial resolution of the reconstructed images beyond the acquired MRI resolution by incorporating information from whole-brain fibre-tracking results. It not only achieves super-resolution, but also provides very high anatomical contrast with a new MRI contrast mechanism. However, the anatomical information-content of this novel contrast mechanism has not yet been assessed. In this work, we perform such a study using diffusion MRI of ex vivo mouse brains acquired at 16.4T, to compare the results of the super-resolution TDI technique with histological staining (myelin and Nissl stains) in the same brains. Furthermore, a modified version of the directionally-encoded colour TDI map using short-tracks is introduced, which reduces the TDI intensity dynamic range, and therefore enhances the directionality colour-contrast. Good agreement was observed between structures visualised in the super-resolution TDI maps and in the histological sections, supporting the anatomical information-content of the images generated using the TDI technique. The results therefore show that the TDI methodology does provide meaningful and rich anatomical contrast, in addition to achieving super-resolution. Furthermore, this study is the first to show the application of TDI to mouse brain imaging: the high-resolution, high-quality images demonstrate the useful complementary information that can be achieved using super-resolution TDI. [Display omitted] ► Track-density imaging (TDI): method recently introduced to gain spatial-resolution. ► We assess the anatomical information-content of TDI using ex vivo mouse data. ► Modified directional-encoded color TDI method is described with enhanced contrast. ► Structures visualised in TDI maps consistent with those in histological sections. ► First study to show the application of super-resolution TDI to mouse brain imaging.