Introduction Radiofrequency planar microcoils are used to increase the resolution of magnetic resonance images of small samples. In this study, we aimed to design and fabricate a spiral planar microcoil constructed on a double-sided printed circuit board (PCB). It has four rings with an internal diameter of 241 microns tuned and matched at 63.8 MHz. Materials and Methods To achieve the maximum ...

Two commercially available plastic keyboards were contrasted in the degree to which they interfered with echo planar imaging. One keyboard (GrandTec USA's "Virtually Indestructible Keyboard") caused significantly less temporally variant and invariant signal loss and was integrated into a MRI interface system for recording participants' manual motor responses. The response recording system is sa...

PURPOSE MR measurements from an echo-planar imaging (EPI) sequence produce Nyquist ghost artifacts that originate from inconsistencies between odd and even echoes. Several reconstruction algorithms have been proposed to reduce such artifacts, but most of these methods require either additional reference scans or multipass EPI acquisition. This article proposes a novel and accurate single-pass E...

PURPOSE Physiological noise often dominates the blood-oxygen level-dependent (BOLD) signal fluctuations in high-field functional MRI (fMRI) data. Therefore, to optimize fMRI protocols, it becomes crucial to investigate how physiological signal fluctuations impact various acquisition and reconstruction schemes at different acquisition speeds. In particular, further differences can arise between ...

While the advantages of parallel acquisition techniques for echo-planar imaging (EPI) are well documented for studies affected by magnetic field inhomogeneities, this work focuses on the costs in functional MRI of brain regions without artifacts due to susceptibility effects. For a visual stimulation paradigm and relative to conventional EPI (2.9 T; TR/TE=2000/36 ms), the use of parallel acquis...

In population groups where head pose cannot be assumed to be constant during a magnetic resonance spectroscopy examination or in difficult-to-shim regions of the brain, real-time volume of interest, frequency, and shim optimization may be necessary. We investigate the effect of pose change on the B0 homogeneity of a (2 cm)3 volume and observe typical first-order shim changes of 1 μT/m per 1° ro...

PURPOSE To implement a method using a tailored radiofrequency (TRF) pulse with a quadratic phase profile to recover susceptibility-induced signal losses in gradient-recalled echo-planar images (EPI). MATERIALS AND METHODS A functional magnetic resonance imaging (fMRI) experiment for compensation of susceptibility artifacts, known as the TRF pulse EPI sequence (TRF-EPI), was used. TRF pulse co...