Regional cerebral blood flow (rCBF) was assessed using dynamic susceptibility-contrast MRI at 1.5 T. A simultaneous dual FLASH pulse sequence and Gd-DTPA-BMA (0.3 mmol/kg b.w.) were used for examination of 43 volunteers, measuring rCBF in frontal white matter (WM) gray the thalamus (GM). Arterial input functions (AIFs) registered 1) carotid artery 2) an within GM/WM slice. The measured concentration-vs.-time curve deconvolved with AIF both Fourier Transform (FT) Singular Value Decomposition...

The aim of this study was to improve the accuracy and precision perfusion fraction blood velocity dispersion estimates in intravoxel incoherent motion (IVIM) imaging, using joint analysis flow‐compensated non‐flow‐compensated motion‐encoded MRI data. A double diffusion encoding sequence capable switching between modes implemented. In vivo brain data were collected eight healthy volunteers processed analysis. Simulations used compare performance proposed method with conventional IVIM With...

Abstract Purpose: To provide estimates of the diffusional kurtosis in healthy brain anatomically defined areas and list these along previously reported values pathologies. Materials Methods: Thirty‐six volunteers (mean age = 33.1 years; range, 19–64 years) underwent imaging. Mean (MK), radial (RK), mean diffusivity (MD), (RD), fractional anisotropy (FA) were determined 26 anatomical structures. Parameter assessed regarding dependence. Results: MK varied from 1.38 splenium corpus callosum to...

Objective: Perfusion-related parameters obtained by intravoxel incoherent motion (IVIM) MR imaging (MRI) were compared with cerebral blood volume and flow (CBV CBF), retrieved dynamic susceptibility-contrast (DSC) MRI. Material Methods: Twenty-eight volunteers (average age 68.5 years) investigated. Spin-echo echo-planar IVIM-encoding gradients was employed (36 different b values, 0-1200 s/mm 2 ). The perfusion fraction the pseudo-diffusion coefficient calculated for regions in thalamus gray...

To compare absolute cerebral blood flow (CBF) estimates obtained by dynamic susceptibility contrast MRI (DSC-MRI) and Xe-133 SPECT.CBF was measured in 20 healthy volunteers using DSC-MRI at 3T SPECT. accomplished gradient-echo EPI CBF calculated a time-shift-insensitive deconvolution algorithm regional arterial input functions (AIFs). improve the reproducibility of AIF registration time integral rescaled use venous output function. In SPECT experiment, gas inhaled over 8 minutes...

Abstract A new technique for assessing tissue blood flow using hyperpolarized tracers, based on the fact that magnetization of a substance can be destroyed permanently, is described. Assessments with this are inherently insensitive to arterial delay and dispersion, allow quantification transit time dispersion in arteries supply investigated tissue. Renal cortical was studied six rabbits 13 C‐labeled compound (2‐hydroxyethylacrylate) polarized by parahydrogen‐induced polarization (PHIP)...

Abstract The Rician distribution of noise in magnitude magnetic resonance (MR) images is particularly problematic low signal‐to‐noise ratio (SNR) regions. causes a nonzero minimum signal the image, which often referred to as rectified floor. True likely be concealed noise, and quantification severely hampered low‐SNR To address this problem we performed reduction (or denoising) by Wiener‐like filtering wavelet domain. was applied complex MRI data before construction image. noise‐reduction...

Abstract The aim of this study was to investigate the diffusion time dependence signal‐ versus ‐ b curves obtained from diffusion‐weighted magnetic resonance imaging (DW‐MRI) sub‐acute ischaemic lesions in stroke patients. In case series study, 16 patients with were examined DW‐MRI using two different times (60 and 260 ms). Nine these showed sufficiently large without artefacts merit further analysis. plotted analysed a two‐compartment model including compartmental exchange. To validate aid...

The arterial input function is crucial in pharmacokinetic analysis of dynamic contrast-enhanced MRI data. Among other artifacts quantification, the blood inflow effect and nonideal radiofrequency spoiling can induce large measurement errors with subsequent reduction accuracy parameters. These were investigated for a 3D spoiled gradient-echo sequence using pulsatile flow phantom total 144 typical imaging settings. In presence effects, results showed poor average spread between settings, when...

<h3>BACKGROUND AND PURPOSE:</h3> The arterial spin-labeling method for CBF assessment is widely available, but its accuracy not fully established. We investigated the of a whole-brain technique assessing mean parenchymal and effect aging in healthy volunteers. Phase-contrast MR imaging was used as reference method. <h3>MATERIALS METHODS:</h3> Ninety-two volunteers were included: 49 young (age range, 20–30 years) 43 elderly 65–80 years). Arterial values averaged over whole brain to quantify...

Abstract Purpose: To investigate if resting‐state functional MRI (fMRI) reliably can serve as a complement to task‐based fMRI for presurgical mapping of the sensorimotor cortex. Materials and Methods: Functional data were obtained in 10 healthy volunteers using 3 Tesla system. Each subject performed five bilateral finger tapping experiments interleaved with experiments. Following preprocessing, from eight further analyzed general linear model (finger data) independent component analysis...

Purpose Arterial partial-volume effects (PVEs) often hamper reproducible absolute quantification of cerebral blood flow (CBF) and volume (CBV) obtained by dynamic susceptibility contrast MRI (DSC-MRI). The aim this study was to examine whether arterial PVEs in DSC-MRI data can be minimized rescaling the input function (AIF) using a sagittal-sinus venous output following prebolus administration low dose agent. Methods carried out as test–retest experiment 20 healthy volunteers repeatability...