Functional connectivity analysis of resting state blood oxygen level-dependent (BOLD) functional MRI is widely used for noninvasively studying brain functional networks. Recent findings have indicated, however, that even small (≤1 mm) amounts of head movement during scanning can disproportionately bias connectivity estimates, despite various preprocessing efforts. Further complications for inte...

Interleaved echo-planar imaging (EPI) is susceptible to significant ghosting artifacts, resulting primarily from system time delays that cause data matrix misregistration. Most EPI applications rely on "reference scans" to measure delays, and post-processing algorithms are used to correct these errors. Unfortunately, delay estimates made with most reference scan techniques are object dependent,...

fMRI retinotopic mapping usually relies upon Fourier analysis of functional responses to periodic visual stimuli that encode eccentricity or polar angle in the visual field. Generally, phase estimations are assigned to a surface model of the cerebral cortex and borders between retinotopic areas are eventually determined following ad hoc phase analysis on the surface model. Assigning functional ...

A fast T(1) measurement sequence using inversion recovery Look-Locker echo-planar imaging at steady state (IR LL-EPI SS) is presented. Delay time for a full magnetization recovery is not required in the sequence, saving acquisition time significantly for high-resolution T(1) mapping. Imaging parameters of the IR LL-EPI SS sequence were optimized to minimize the bias from the excitation pulses i...

Diffusion imaging acquired with echo-planar imaging (EPI) is usually performed with parallel imaging to reduce geometric distortions, especially at high fields. This study reports the occurrence of pseudolesions in EPI with parallel imaging. The unfolding artifacts are attributed as arising from a mismatch between RF sensitivity profiles and distorted acquisition data in the presence of suscept...

The accuracy of measuring voxel intensity changes between stimulus and rest images in fMRI echo-planar imaging (EPI) data is severely degraded in the presence of head motion. In addition, EPI is sensitive to susceptibility-induced geometric distortions. Head motion causes image shifts and associated field map changes that induce different geometric distortion at different time points. Conventio...

A novel image encoding approach based on linear frequency-swept excitation has been recently proposed to overcome artifacts induced by various field perturbations in single-shot echo planar imaging. In this article, we develop a new super-resolved reconstruction method for it using the concepts of local k-space and partial Fourier transform. This method is superior to the originally developed c...

PURPOSE To improve the traditional Nyquist ghost correction approach in echo planar imaging (EPI) at high fields, via schemes based on the reversal of the EPI readout gradient polarity for every other volume throughout a functional magnetic resonance imaging (fMRI) acquisition train. MATERIALS AND METHODS An EPI sequence in which the readout gradient was inverted every other volume was implem...

Objectives: To explore the diagnostic value of 99mTc-Sestamibi multiple-phase static planar imaging and SPECT/CT in secondary hyperparathyroidism. Methods: This was a retrospective analysis of 40 cases of clinically diagnosed secondary hyperparathyroidism with multiple-phase static planar imaging, 15 min SPECT/CT fusion imaging, and ultrasonography. All cases were confirmed by pathological exam...

Introduction: Despite widespread use of 67Gallium for lymphoma evaluation, timing of imaging after injection is a matter of controversy and to the extent of our knowledge no direct comparison has been made between early and delayed gallium images. We aimed to compare 24 and 48 hours post injection planar gallium imaging for evaluation of lymphoma recurrence. Methods: 255 pa...