PURPOSE To determine whether a relationship exists between water diffusion coefficients or diffusion anisotropy and MR-defined regions of normal or abnormal brain parenchyma in patients with cerebral gliomas. METHODS In 40 patients with cerebral gliomas, diffusion was characterized in a single column of interest using a motion-insensitive spin-echo sequence that was applied sequentially at tw...

Generalized diffusion tensor imaging (GDTI) was developed to model complex apparent diffusivity coefficient (ADC) using higher-order tensors (HOTs) and to overcome the inherent single-peak shortcoming of DTI. However, the geometry of a complex ADC profile does not correspond to the underlying structure of fibers. This tissue geometry can be inferred from the shape of the ensemble average propag...

There is a general need for spacecraft systems to make use of advances in analog to digital (ADC) and digital to analog (DAC) technologies. In particular, imaging systems such as star trackers and remote sensing instruments require 14,16, or more bits ADCs that have low power consumption, fast conversion rates (>1 MSPS) and good radiation tolerances. Because ADC and DAC have both analog and dig...

PURPOSE To determine the optimal combination of parameters derived from 3T multiparametric (conventional magnetic resonance imaging [MRI], diffusion-weighted [DW] and dynamic contrast-enhanced [DCE]) MRI for differentiating malignant from benign orbital lymphoproliferative disorders (OLPDs). MATERIALS AND METHODS Forty patients with OLPDs (18 benign and 22 malignant) underwent conventional 3....

BACKGROUND AND PURPOSE DWI is typically performed with EPI sequences in single-center studies. The purpose of this study was to determine the reproducibility of ADC values in the head and neck region in healthy subjects. In addition, the reproducibility of ADC values in different tissues was assessed to identify the most suitable reference tissue. MATERIALS AND METHODS We prospectively studie...

This work describes a 12-bit 100 MS/s 0.13 μm CMOS three-stage pipeline ADC with various circuit design techniques to reduce power and die area. Digitally controlled timing delay and gatebootstrapping circuits improve the linearity and sampling time mismatch of the SHA-free input network composed of an MDAC and a FLASH ADC. A single two-stage switched op-amp is shared between adjacent MDACs wit...

conclusion adc, fa, and t2* values may quantitatively reflect the microstructural characteristics of np, therefore they could be used to detect the minimal changes of early ldd. results the adc, fa, and t2* values were different (p < 0.05) among different rois within the same disc or among corresponding rois in different level discs. while the average values of adc increased regularly with the ...

background: early diagnosis of brain tumors has significant effect on the treatment process. brain metastatic tumors are usually diagnosed following the neurological symptoms in patients or incidentally after computerized tomography (ct) scan and magnetic resonance imaging (mri) requests of the brain. objectives: implementation of a new method for being informed about the origin of brain tumors...

BACKGROUND Diffusion tensor cardiac magnetic resonance (DT-CMR) enables probing of the microarchitecture of the myocardium, but the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) reported in healthy volunteers have been inconsistent. The aim of this study was to validate a stimulated-echo diffusion sequence using phantoms, and to assess the intercentre reproducibility of in...

PURPOSE To evaluate the normal brains of adults and neonates for regional and age-related differences in apparent diffusion coefficient (ADC) and fractional anisotropy (FA). MATERIALS AND METHODS Eight healthy adults and 20 healthy neonates were examined with a 3.0-T head-only magnetic resonance (MR) imaging unit by using a single-shot diffusion-tensor sequence. Trace ADC maps, FA maps, direc...