Multiscale structural analysis of mouse lingual myoarchitecture employing diffusion spectrum magnetic resonance imaging and multiphoton microscopy

Abstract

Abstract. The tongue consists of a complex, multiscale array of myofibers that comprise the anatomical underpinning of lingual mechanical function. 3-D myoarchitecture was imaged in mouse tongues with diffusion spectrum magnetic resonance imaging ͑DSI͒ at 9.4 T ͑b max 7000 s / mm, 150-m isotropic voxels͒, a method that derives the preferential diffusion of water/voxel, and high-throughput ͑10 fps͒ two-photon microscope ͑TPM͒. Net fiber alignment was represented for each method in terms of the local maxima of an orientational distribution function ͑ODF͒ derived from the local diffusion ͑DSI͒ and 3-D structural autocorrelation ͑TPM͒, respectively. Mesoscale myofiber tracts were generated by alignment of the principal orientation vectors of the ODFs. These data revealed a consistent relationship between the properties of the respective ODFs and the virtual superimposition of the distributed mesoscale myofiber tracts. The identification of a mesoscale anatomical construct, which specifically links the microscopic and macroscopic spatial scales, provides a method for relating the orientation and distribution of cells and subcellular components with overall tissue morphology, thus contributing to the development of multiscale methods for mechanical analysis.

In vivo 3 T MR diffusion tensor imaging for detection of the fibre architecture of the human uterus: a feasibility and quantitative study

“…The newest applications propose diffusion spectrum imaging (DSI) as an evolution of DTI, which has a higher quality of angular resolution in 3D, particularly useful to visualise deeply crossed fibres, but it has a long sequence run time and it is not applicable in vivo. Recent animal studies analysed myocardium in rat hearts, bovine tongue and rat optic tracts with DTI and DSI, but at present hardware limitations hamper most of the clinical applications [19,20]. It is hoped that as MR-DTI software and hardware improve and a uterine-specific fibre tracking algorithm is refined, we can expect a higher spatial resolution with decreased acquisition time.…”

Patterns of Intersecting Fiber Arrays Revealed in Whole Muscle with Generalized Q-Space Imaging

“…The use of gradient pulses of varying orientations, intensities, and sampling times enables the interrogation of complex microstructural anisotropic features at varying spatial scales (38). In particular, multiscale diffusion imaging is enabled through the linkage of the diffusion PDF maxima via tractography, enabling visualization of subvoxel phenomenon at the multivoxel scale (10,18,19).…”

“…Angular separation so defined forms the underlying construct of the myofiber tract (mesoscale) obtained during streamlining, linking PDF diffusional maxima from one voxel to neighboring voxels. Tract coherence is, in turn, dependent upon voxel-scale angular resolution and the allowable tract generation angle, and has been validated through histological comparison (16,17,39) and microscopic correlation (14,38).…”

“…Voxelwise selection of a particular PDF into a userdefined region of interest (ROI) was completed in individual slices using the anisotropy map, and in three dimensions with the EPI B ¼ 0 images. Tracts were selectively generated that intersect a ROI through demonstrated intervoxel coherence fixed within a range of 517.5 from PDF maxima, selected based on past studies, and as has been substantively validated with correlation to microscopic imaging methods (14,38). Tracts that intersected the ROI were displayed and generated from uniformly distributed seeding points within each voxel of the dataset.…”

“…To define the microscopic determinants of GQI, we observed comparative fiber direction in multiple sagittal slices (38). Employing wild-type CD-1 mice, the lower jaw was excised, skinned, and immersed into low MRsignal fluorinated Krytox oil (Dupont, Wilmington, DE).…”