Functional magnetic resonance imaging (fMRI) time series analysis is typically performed using only the magnitude portion of the data. The phase information remains unused largely due to its sensitivity to temporal variations in the magnetic field unrelated to the functional response of interest. These phase changes are commonly the result of physiologic processes such as breathing or motion ei...

Echo-planar imaging is the dominant functional MRI data acquisition scheme for evaluating the BOLD signal. To date, it remains the only approach providing neurofeedback from spatially localized brain activity. Real-time functional single-voxel proton spectroscopy (fSVPS) may be an alternative for spatially specific BOLD neurofeedback at 7T because it allows for a precise estimation of the local...

We have discovered a simple and highly robust method for removal of chemical shift artifact in spin-echo MR images, which simultaneously decreases the radiofrequency power deposition (specific absorption rate). The method is demonstrated in spin-echo echo-planar imaging brain images acquired at 7 T, with complete suppression of scalp fat signal. When excitation and refocusing pulses are suffici...

A multislice EPI sequence was used to obtain functional MR images of the entire rat brain with BOLD contrast at 11.7 T. Ten to 11 slices covering the rat brain, with an in-plane resolution of 300 microm, provided enough sensitivity to detect activation in brain regions known to be involved in the somatosensory pathway during stimulation of the forelimbs. These regions were identified by warping...

Small gradient fields resulting from incompletely canceled eddy currents can cause geometric distortion in echo-planar images. Although this distortion is negligible in most echoplanar applications, the large gradient pulses used in diffusion-weighted echo-planar imaging can result in significant image distortion. In this report, it is shown that this distortion can be significantly reduced by ...

We investigated the characteristics of the hemodynamic response (HDR) to paired presentations of visual face stimuli using functional magnetic resonance imaging (fMRI). Photographs of faces were presented singly or in pairs with either a 1-s or 6-s intrapair interval (IPI). Each trial (single face or face pairs) was followed by an intertrial interval of 16-20 s. Faces were presented at fixation...

Diffusion magnetic resonance studies of the brain are typically performed using volume coils. Although in human brain this leads to a near optimal filling factor, studies of rodent brain must contend with the fact that only a fraction of the head volume can be ascribed to the brain. The use of surface coil as transceiver increases Signal-to-Noise Ratio (SNR), reduces radiofrequency power requir...

EEG recordings made in combined EEG-fMRI studies are corrupted by gradient artefacts (GAs) resulting from the interaction of the EEG system with the time-varying magnetic field gradients used in MRI. The dominant contribution to the GA arises from interaction with the leads of the EEG cap and the human head, but artefacts are also produced in the cables used to connect the EEG cap to the amplif...

An interleaved gradient-echo echo-planar imaging (IGEPI) sequence was modified for and applied to dynamic contrast-enhanced imaging of the heart. Using IGEPI, images with 3.0 x 3.9 mm nominal in-plane resolution are acquired in 100 ms, enabling eight slices per heartbeat for a heart rate of 60 beats/min. The acquisition speed and use of saturation prepulses allows acquisition of short- and long...

A new method for functional magnetic resonance imaging (fMRI) employing non-Fourier encoding using spatially selective radiofrequency (RF) excitation is presented. The method uses manipulation of spatially selective RF pulses to encode spins in the slice-select direction. The method has several advantages over standard multislice approaches. It provides a simple means for monitoring irregularly...