User profiles for Joseph A. Helpern

Joseph A. Helpern

New Vision Research
Verified email at musc.edu
Cited by 19173

MRI quantification of non‐Gaussian water diffusion by kurtosis analysis

JH Jensen, JA Helpern - NMR in Biomedicine, 2010 - Wiley Online Library
Quantification of non‐Gaussianity for water diffusion in brain by means of diffusional kurtosis
imaging (DKI) is reviewed. Diffusional non‐Gaussianity is a consequence of tissue structure …

Diffusional kurtosis imaging: the quantification of non‐gaussian water diffusion by means of magnetic resonance imaging

JH Jensen, JA Helpern, A Ramani, H Lu… - … in Medicine: An …, 2005 - Wiley Online Library
A magnetic resonance imaging method is presented for quantifying the degree to which water
diffusion in biologic tissues is non‐Gaussian. Since tissue structure is responsible for the …

Estimation of tensors and tensor‐derived measures in diffusional kurtosis imaging

…, JH Jensen, BA Ardekani, JA Helpern - Magnetic resonance in …, 2011 - Wiley Online Library
This article presents two related advancements to the diffusional kurtosis imaging estimation
framework to increase its robustness to noise, motion, and imaging artifacts. The first …

White matter characterization with diffusional kurtosis imaging

E Fieremans, JH Jensen, JA Helpern - Neuroimage, 2011 - Elsevier
Diffusional kurtosis imaging (DKI) is a clinically feasible extension of diffusion tensor
imaging that probes restricted water diffusion in biological tissues using magnetic resonance …

Three‐dimensional characterization of non‐gaussian water diffusion in humans using diffusion kurtosis imaging

…, JH Jensen, A Ramani, JA Helpern - NMR in Biomedicine: An …, 2006 - Wiley Online Library
Conventional diffusion tensor imaging (DTI) measures water diffusion parameters based on
the assumption that the spin displacement distribution is a Gaussian function. However, …

Monte Carlo study of a two‐compartment exchange model of diffusion

…, DS Novikov, JH Jensen, JA Helpern - NMR in …, 2010 - Wiley Online Library
Multisite exchange models have been applied frequently to quantify measurements of
transverse relaxation and diffusion in living tissues. Although the simplicity of such models is …

Assessment of relative brain iron concentrations using T2‐weighted and T2*‐weighted MRI at 3 Tesla

…, JC Deniau, RA Knight, JA Helpern - Magnetic resonance …, 1994 - Wiley Online Library
In this paper a new method is presented for the relative assessment of brain iron concentrations
based on the evaluation of T 2 and T 2 * ‐weighted images. A multiecho sequence is …

Revealing mesoscopic structural universality with diffusion

DS Novikov, JH Jensen, JA Helpern… - Proceedings of the …, 2014 - National Acad Sciences
Measuring molecular diffusion is widely used for characterizing materials and living organisms
noninvasively. This characterization relies on relations between macroscopic diffusion …

Correction of motional artifacts in diffusion-weighted MR images using navigator echoes

RJ Ordidge, JA Helpern, ZX Qing, RA Knight… - Magnetic resonance …, 1994 - Elsevier
Patient motion can seriously degrade the quality of diffusion-weighted MR images obtained
using standard 2DFT imaging procedures. The main source of error arises from an MR …

Does diffusion kurtosis imaging lead to better neural tissue characterization? A rodent brain maturation study

MM Cheung, ES Hui, KC Chan, JA Helpern, L Qi… - Neuroimage, 2009 - Elsevier
Diffusion kurtosis imaging (DKI) can be used to estimate excess kurtosis, which is a dimensionless
measure for the deviation of water diffusion profile from Gaussian distribution. Several …