R. Reeve Ingle

Nonrigid Autofocus Motion Correction for Coronary MR Angiography with a 3D Cones Trajectory

To implement a nonrigid autofocus motion correction technique to improve respiratory motion correction of free‐breathing whole‐heart coronary magnetic resonance angiography acquisitions using an image‐navigated 3D cones sequence.

High‐resolution variable‐density 3D cones coronary MRA

To improve the spatial/temporal resolution of whole‐heart coronary MR angiography by developing a variable‐density (VD) 3D cones acquisition suitable for image reconstruction with parallel imaging and compressed sensing techniques.

Parameter estimation approach to banding artifact reduction in balanced steady-state free precession

The balanced steady‐state free precession (bSSFP) pulse sequence has shown to be of great interest due to its high signal‐to‐noise ratio efficiency. However, bSSFP images often suffer from banding artifacts due to off‐resonance effects, which we aim to minimize in this article.

Self-gated fat-suppressed cardiac cine MRI.

To develop a self‐gated alternating repetition time balanced steady‐state free precession (ATR‐SSFP) pulse sequence for fat‐suppressed cardiac cine imaging.

Detection, identification, location, and remote sensing using SAW RFID sensor tags

We consider the problem of simultaneous detection, identification, location estimation, and remote sensing for multiple objects in an environment. In particular, we describe the design and performance of a system capable of simultaneously detecting the presence of multiple objects, identifying each object, and acquiring both a low-resolution estimate of location and a high-resolution estimate of temperature for each object based on wireless interrogation of passive surface acoustic wave (SAW) radio-frequency identification (RFID) sensor tags affixed to each object. The system is being studied for application on the lunar surface as well as for terrestrial remote sensing applications such as pre-launch monitoring and testing of spacecraft on the launch pad and monitoring of test facilities. The system utilizes a digitally beam-formed planar receiving antenna array to extend range and provide direction-of-arrival information coupled with an approximate maximum-likelihood signal processing algorithm to provide near-optimal estimation of both range and temperature. We examine the theoretical performance characteristics of the system and compare the theoretical results with results obtained from controlled laboratory experiments.1,2

Nonrigid motion correction with 3D image-based navigators for coronary MR angiography

To develop a retrospective nonrigid motion‐correction method based on 3D image‐based navigators (iNAVs) for free‐breathing whole‐heart coronary magnetic resonance angiography (MRA).

Combined Outer Volume Suppression and T2 Preparation Sequence for Coronary Angiography

To develop a magnetization preparation sequence for simultaneous outer volume suppression (OVS) and T2 weighting in whole‐heart coronary magnetic resonance angiography.

3D image‐based navigators for coronary MR angiography

To develop a method for acquiring whole‐heart 3D image‐based navigators (iNAVs) with isotropic resolution for tracking and correction of localized motion in coronary magnetic resonance angiography (CMRA).

The central signal singularity phenomenon in balanced SSFP and its application to positive-contrast imaging.

Small perturbations of steady‐state sequence parameters can induce very large spectral profile deviations that are localized to specific off‐resonant frequencies, denoted critical frequencies. Although, a small number of studies have previously considered the use of these highly specific modulations for MR angiography and elastography, many potential applications still remain to be explored. An analysis of this phenomenon using a linear systems technique and a geometric magnetization trajectory technique shows that the critical frequencies correspond to singularities in the steady‐state signal equation. An interleaved acquisition combined with a complex difference technique yields a spectral profile containing sharp peaks interleaved with wide stopbands, while a complex sum technique yields a spectral profile similar to that of balanced steady‐state free precession. Simulations and phantom experiments are used to demonstrate a novel application of this technique for positive‐contrast imaging of superparamagnetic iron‐oxide nanoparticles. The technique is shown to yield images with high levels of positive contrast and good water and fat background suppression. The technique can also simultaneously yield images with contrast similar to balanced steady‐state free precession. Magn Reson Med, 2011.

Accelerated isotropic resolution 3D image-based navigators for coronary MR angiography

Background Motion remains a primary challenge for MR coronary angiography. In our previous protocol, we performed retrospective 3D motion correction based on a set of orthogonal 2D image-based navigators (iNAV) [1]. Recent work examined the use of anisotropic-resolution 3D Cartesian iNAVs every heartbeat [2]. Capitalizing on the efficiency of non-Cartesian imaging and iterative reconstruction, we sought an improved 3D iNAVs acquisition with isotropic resolution, to facilitate wholeheart motion correction with translational or more advanced models. In this work, we propose a method providing 3D motion correction on a per-heartbeat basis using a variable-density 3D cones iNAV acquisition [3].