Signal variability in diffusion weighted imaging (DWI) is influenced by both thermal noise and spatially and temporally varying artifacts such as subject motion and cardiac pulsation. In this paper, the effects of DWI artifacts on estimated tensor values, such as trace and fractional anisotropy, are analyzed using Monte Carlo simulations. A novel approach for robust diffusion tensor estimation,...

Recently, we measured two anomalous diffusion (AD) parameters: the spatial and the temporal AD indices, called γ and α, respectively, by using spectroscopic pulse gradient field methods. We showed that γ quantifies pseudo-superdiffusion processes, while α quantifies subdiffusion processes. Here, we propose γ and α maps obtained in a controlled heterogeneous phantom, comprised of packed micro-be...

Introduction Fetal MR brain imaging is proving to be a powerful modality with which to evaluate the developing fetal brain. Advanced imaging strategies, such as diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) have recently been applied to the human fetus [1,2]. The major difficulty of performing DWI of the fetal brain in utero is the presence of motion, which is especially m...

Introduction Diffusion kurtosis imaging is a new method to estimate the non gaussianity of the diffusion process with diffusion weighted MR images (DWIs) [1]. The model of the DWIs suggested in [1] was based on the Taylor series expansion of the logarithm of the DW magnitude. Unfortunately, this Taylor approximation is only valid for small b-values and leads to diverging predicted DW magnitudes...

Diffusion-weighted imaging (DWI) is the most effective component of the modern multi-parametric magnetic resonance imaging (mpMRI) scan for prostate pathology. DWI provides the strongest prediction of cancer volume, and the apparent diffusion coefficient (ADC) correlates moderately with Gleason grade. Notwithstanding the demonstrated cancer assessment value of DWI, the standard measurement and ...

BACKGROUND AND PURPOSE We investigated 2 methods of measuring MR imaging perfusion-diffusion mismatch to determine whether reliability is improved by direct measurement on a single, blended map. MATERIALS AND METHODS Image software was used for measurement of lesion volumes from diffusion-weighted images (DWI) and mean transit time (MTT) calculated from perfusion-weighted (PWI) images on 64 p...

We report the case of malignant oligodendroglioma in a 36-year-old man who underwent diffusion-weighted, perfusion-weighted, and volumetric MR imaging before and after PCV (procarbazine, CCNU, vincristine) chemotherapy. The tumor regions exhibiting a low apparent diffusion coefficient and increased relative cerebral blood volume showed a marked response to chemotherapy and dramatic decrease in ...

acquired (+) and computed DWI imaging (x) where the acquisition time is kept the same for both. It is seen that noise remains constant across b-values for the conventionally acquired images whereas for cDWI it reduces with b-value as predicted by equation 1 (dotted curve). It is seen that for high b-values (>700 s mm) the SNR of cDWI is improved compared to conventional imaging. Figure 1. An ex...

Introduction Conventional MR imaging does not provide reliable information on tumor physiology such as microvascularity, angiogenesis or tumor cellularity, all of which are important in determing tumor grade. Advanced MR imaging techniques such as diffusion (DWI), perfusion (PWI) can provide important physiological information in brain tumors. Diffusion tensor metrics such as fractional anisotr...

Alzheimer's disease (AD) and Vascular Dementia (VaD) are the most common types of dementia and are progressive diseases affecting millions of people. Despite the high sensitivity of MRI to neurological disorders it has not thus far been found to be specific for the detection of either of these pathologies. In the present study high b-value q-space diffusion-weighted MRI (DWI) was applied to VaD...