Direct visualization of small anisotropic brain structures using high resolution, multi-shell diffusion MRI

In vivo visualization and quantitative assessment of small anisotropic brain structures is challenging with diffusion MRI because of signal-to-noise limitations. We show that direct visualization of small structures, like the fornix or stria medullaris, dramatically improves using denoised 1-mm isotropic resolution complex-valued dMRI data. This approach also reduces the bias and variance of diffusion parameter estimations for small structures. Increased resolution with denoising decreases parameter variance due to thermal noise and partial volume effects – these data also can be used to better estimate the true biological variance in a structure by extrapolating the data to the infinite SNR limit.