Super Slice Interpolation For Generating Thin-Slice Images From Multichannel Multislice MRI Data.

This study aims to develop a super slice interpolation (SSI) method that generates thin-slice images from multichannel multislice images by exploiting the intra-slice coil sensitivity variations. SSI first calculates the thin-slice sensitivity maps by through-plane interpolation of the sensitivity maps computed from the acquired multislice images. It then reconstructs multiple thin-slice images from each acquired image using a through-plane regularized sensitivity encoding (SENSE) like procedure that consists of an initial SENSE reconstruction and denoising to set the prior information image, and subsequent regularized SENSE reconstruction.

Robust SENSE reconstruction of simultaneous multislice EPI with low-rank enhanced coil sensitivity calibration and slice-dependent 2D Nyquist ghost correction.

Purpose: To improve simultaneous multislice (SMS) EPI by robust Nyquist ghost correction in both coil sensitivity calibration and SMS reconstruction.

Methods: To derive coil sensitivity and slice-dependent phase difference map between positive- and negative-echo images, single-band EPI reference data are fully sampled with EPI parameters matched to SMS acquisition. First, the reference data are organized into positive- and negative-echo virtual channels where missing data are estimated using low-rank-based simultaneous autocalibrating and k-space estimation (SAKE) at small matrix size.

Robust EPI Nyquist ghost removal by incorporating phase error correction with sensitivity encoding (PEC-SENSE).

Purpose: The existing approach of Nyquist ghost correction by parallel imaging in echo planar imaging (EPI) can suffer from image noise amplification. We propose a method that estimates a phase error map from multi-channel data itself and incorporates it into the sensitivity encoding (SENSE) reconstruction for Nyquist ghost correction without compromising the image SNR.

Methods: This method first reconstructs two ghost-free images from positive and negative echoes using SENSE, respectively, from which the phase error map is computed.

Simultaneous spin-echo and gradient-echo BOLD measurements by dynamic MRS.

This study aimed to dissociate the intravascular and extravascular contributions to spin-echo (SE) and gradient-echo (GE) blood oxygenation level-dependent (BOLD) signals at 7 T, using dynamic diffusion-weighted MRS. We simultaneously acquired SE and GE data using a point-resolved spectroscopy sequence with diffusion weightings of 0, 600, and 1200 s/mm . The BOLD signals were quantified by fitting the free induction decays starting from the SE center to a mono-exponential decay function.

A New Joint-Blade SENSE Reconstruction for Accelerated PROPELLER MRI.

PROPELLER technique is widely used in MRI examinations for being motion insensitive, but it prolongs scan time and is restricted mainly to T2 contrast. Parallel imaging can accelerate PROPELLER and enable more flexible contrasts. Here, we propose a multi-step joint-blade (MJB) SENSE reconstruction to reduce the noise amplification in parallel imaging accelerated PROPELLER.

EPI Nyquist ghost and geometric distortion correction by two-frame phase labeling.

Purpose: To develop a new Nyquist ghost and geometric distortion correction method in echo planar imaging (EPI) using parallel imaging.

Methods: Two frames of EPI data are acquired with normal and phase-labeled sequence. The phase label is applied by modifying the PE prephase gradient to shift the central echo by one echo spacing.

Diffusion magnetic resonance monitors intramyocellular lipid droplet size in vivo.

Purpose: Intramyocellular lipid (IMCL) droplets are dynamic organelles whose morphology reflects their vital roles in lipid synthesis, usage, and storage in muscle energy metabolism. To develop noninvasive means to measure droplet microstructure in vivo, we investigated the molecular diffusion behavior of IMCL with diffusion magnetic resonance spectroscopy.

Methods: Using extremely large diffusion weighting, we measured the IMCL apparent diffusion coefficients (ADCs) in hindlimb muscle of rodents from normal feeding, 60-h fasting, streptozotocin-induced diabetic, and high-fat-diet-induced obese groups.