introduction echo-planar imaging (epi) is a group of fast data acquisition methods commonly used in fmri studies. it acquires multiple image lines in k-space after a single excitation, which leads to a very short scan time. a well-known problem with epi is that it is more sensitive to distortions due to the used encoding scheme. source of distortion is inhomogeneity in the static b0 field that ...

introduction as functional magnetic resonance imaging (fmri) is too expensive and time consuming, its frequent implementation is difficult. the aim of this study is to evaluate repeatability of detecting visual cortex activity in fmri. materials and methods in this study, 15 normal volunteers (10 female, 5 male; mean age±sd: 24.7±3.8 years) attended. functional magnetic resonance images were ob...

Typical simultaneous blood oxygenation-level dependent (BOLD) and arterial spin labeling (ASL) sequences acquire two echoes, one perfusion-sensitive and one BOLD-sensitive. However, for ASL, spatial resolution and brain coverage are limited due to the T1 decay of the labeled blood. This study applies a sequence combining a multiband acquisition with four echoes for simultaneous BOLD and pseudo-...

The development of functional magnetic resonance imaging (fMRI) has brought together a broad community of scientists interested in measuring the neural basis of the human mind. Because fMRI signals are an indirect measure of neural activity, interpreting these signals to make deductions about the nervous system requires some understanding of the signaling mechanisms. We describe our current und...

BACKGROUND AND PURPOSE Recent interest has emerged in the use of pharmacologic methods to maximize blood oxygenation level-dependent (BOLD) signal intensity changes in functional MR imaging (fMRI). Adenosine antagonists, such as caffeine and theophylline, have been identified as potential agents for this purpose. The present study was designed to determine whether caffeine-induced decreases in ...

Functional magnetic resonance imaging (fMRI) techniques are based on the assumption that changes in spike activity are accompanied by modulation in the blood oxygenation level-dependent (BOLD) signal. In addition to conventional increases in BOLD signals, sustained negative BOLD signal changes are occasionally observed and are thought to reflect a decrease in neural activity. In this study, the...

Introduction As functional magnetic resonance imaging (fMRI) is too expensive and time consuming, its frequent implementation is difficult. The aim of this study is to evaluate repeatability of detecting visual cortex activity in fMRI. Materials and Methods In this study, 15 normal volunteers (10 female, 5 male; Mean age±SD: 24.7±3.8 years) attended. Functional magnetic resonance images were ob...