Background Coronary arteries remain challenging structures to image using MRI due to the small size, tortuous course, and continual motion. Current high-resolution whole-heart techniques use prospective ECG-triggering and navigator gating to suppress cardiac and respiratory motion artifacts, respectively. However, these motion suppression strategies only accept data acquired within a narrow win...

Thesis: Implementation of Anatomical Navigators for Real Time Motion Correction in Diffusion Tensor Imaging Author‟s Name: Alkathafi A. Alhamud Date: 10-02-2012 Diffusion Tensor Imaging (DTI) is used to detect microstructural changes in the human brain. Although echo planar imaging (EPI) has been implemented in diffusion pulse sequences to minimize the effect of subject motion, motion artifacts...

INTRODUCTION Spectroscopy scans generally require averaging (over minutes) to obtain acceptable signal-to-noise ratio (SNR). Patient motion compromises the quality and reliability of the resulting spectra. Such concerns are particularly acute with subjects who have difficulty holding still, for instance young children or adults who are in pain or confused. Therefore, we implemented a single-vox...

A major source of artifacts in diffusion-weighted imaging is subject motion. Slow bulk subject motion causes misalignment of data when more than one average or diffusion gradient direction is acquired. Fast bulk subject motion can cause signal dropout artifacts in diffusion-weighted images and results in erroneous derived maps, e.g., fractional anisotropy maps. To address both types of artifact...

PROPELLER T1 FLAIR acquisition with no motion. (stationary), motion with correction for rotation and with no correction for rotation. Top row shows enlargements of the frontal lobes and 2 example slices are shown in the middle and lower rows. Note blurring evident in images with no rotational correction while high image quality is maintained with rotation correction that is comparable to images...

technique and reformatted to display the coronaries (here LAD), (a) were compared to acquisitions performed with the new hybrid method (b). In this case, the vessel sharpness resulted visibly improved in the central and distal parts of the LAD. Figure 1: Schematic description of the hybrid motion correction technique The Next Step in Self-Navigated Coronary MRI: A Hybrid Approach for Affine Mot...

For PET/CT, fast CT acquisition time can lead to errors in attenuation correction, particularly at the lung/diaphragm interface. Gated 4D PET can reduce motion artifacts, though residual artifacts may persist depending on the CT dataset used for attenuation correction. We performed phantom studies to evaluate 4D PET images of targets near a density interface using three different methods for at...

Introduction Intra-cavitary imaging coils have been developed to achieve improvements in image signal-to-noise ratio (SNR) of the order of 5-10, such as those used for prostate, cardiac and arterial wall imaging. This increased local SNR can be used to generate higher spatial resolution. However, since both the anatomy and the coil are moving during imaging, imaging with such coils is more pron...

Despite technical advances, respiratory motion remains a major impediment in a substantial amount of patients undergoing coronary magnetic resonance angiography (CMRA). Traditionally, respiratory motion compensation has been performed with a one-dimensional respiratory navigator positioned on the right hemi-diaphragm, using a motion model to estimate and correct for the bulk respiratory motion ...