Ricardo Coronado-Leija

NYU Langone Medical Center | NYUMC · Department of Radiology

The neocortex is a highly organized structure, with region-specific spatial patterns of cells and fibers constituting cyto- and myelo-architecture, respectively. These architectural features are modulated during neurodevelopment, aging, and disease. While invasive techniques have contributed significantly to our understanding of cortical patterning...

Biophysical modeling of diffusion MRI (dMRI) offers the exciting potential of bridging the gap between the macroscopic MRI resolution and microscopic cellular features, effectively turning the MRI scanner into a noninvasive in vivo microscope. In brain white matter, the Standard Model (SM) interprets the dMRI signal in terms of axon dispersion, int...

The increasing availability of high‐performance gradient systems in human MRI scanners has generated great interest in diffusion microstructural imaging applications such as axonal diameter mapping. Practically, sensitivity to axon diameter in diffusion MRI is attained at strong diffusion weightings , where the deviation from the expected scaling i...

Estimating structural connectivity from diffusion-weighted magnetic resonance imaging is a challenging task, partly due to the presence of false-positive connections and the misestimation of connection weights. Building on previous efforts, the MICCAI-CDMRI Diffusion-Simulated Connectivity (DiSCo) challenge was carried out to evaluate state-of-the-...

Focal cortical dysplasias are a type of malformations of cortical development that are a common cause of drug-resistant focal epilepsy. Surgical treatment is a viable option for some of these patients, with their outcome being highly related to complete surgical resection of lesions visible in magnetic resonance imaging (MRI). However, subtle lesio...

We consider the effect of non-cylindrical axonal shape on axonal diameter mapping with diffusion MRI. Practical sensitivity to axon diameter is attained at strong diffusion weightings b, where the deviation from the 1/radical b scaling yields the finite transverse diffusivity, which is then translated into axon diameter. While axons are usually mod...

The number of fascicles per-voxel N is a crucial parameter for multiple-fiber reconstruction methods from diffusion magnetic resonance imaging (dMRI) data, such as the multi-tensor model (MTM). This parameter is especially important when the goal is to provide bundle-specific tissue metrics. However, for MTM, statistical selection methods, such as...

Diffusion-weighted magnetic resonance imaging (dMRI) is widely used to infer microstructural characteristics of tissue, particularly in cerebral white matter. Histological validation of the metrics derived from dMRI methods are needed to fully characterize their ability to capture biologically-relevant histological features non-invasively. The data...

Axonal degeneration is a hallmark of many neuropathologies, with a defined time course presenting distinct histological features. In single fiber regions, the tensor model provides reliable information in early and chronic phases of axonal damage. However, said model cannot accurately determine per-bundle characteristics in voxels occupied by axona...

Micro-architectural characteristics of white matter can be inferred through analysis of diffusion-weighted magnetic resonance imaging (dMRI). The diffusion-dependent signal can be analyzed through several methods, with the tensor model being the most frequently used due to its straightforward interpretation and relaxed acquisition parameters. While...

To estimate the physical features of intra-voxel axon bundles in the detection of axon damage it is important to compute bundle-wise apparent diffusivities. There is a first family of methods that factors-out the effects of the orientation-dispersion under a convolution model (e.g. Spherical Mean), and a second family that associates the diffusivit...

A stable, accurate and robust-to-noise method for the estimation of the intra-voxel bundle-wise diffusion properties for diffusion-weighted magnetic resonance imaging is presented. The proposed method overcomes some of the limitations of most of the multi-fiber algorithms in the literature and extends them to estimate the diffusion profiles, improv...

The tensor model has been widely used to infer characteristics of white matter through diffusion MRI. Unfortunately, this model does not provide reliable information about crossing fiber regions. Several models have been proposed that seem to overcome the limitations of the tensor. However, biological interpretations of such models are limited by t...

A stable, accurate and robust-to-noise general framework for the estimation of the intra-voxel axial and radial diffusivity parameters for diffusion-weighted magnetic resonance imaging is presented. The method estimates the diffusion profiles at multi-fiber voxels, improving the estimation of the intra-voxel geometry at challenging microstructure c...

Methods: The proposed Multi-resolution Discrete Search (MRDS) method is based on three key ideas: 1) A MRSD to determine the PDD’s; 2) The parameter-free determination of the number of axon bundles using the Bayesian Information Criterion (BIC) and 3) A Simultaneous Denoising and Fitting (SDF) procedure to achieve robustness with respect to noise.