with the arrival of increasingly higher resolution pet systems, small amounts of motion can cause significant blurring in the images, compared to the intrinsic resolutions of the scanners. in this work, we have reviewed advanced correction methods for the three cases of (i) unwanted patient motion, as well as motions due to (ii) cardiac and (iii) respiratory cycles. for the first type of motion...

Background Cardiac motion self-gating is a technique where MRI signal is used to derive motion triggers instead of ECG, which might be problematic in high B0 field or cases where ECG is not accessible (e.g. fetal cardiac imaging). However, the performance of existing cardiac self-gating approaches have not yet enabled clinical utility. We propose and evaluate here a novel cardiac self-gating st...

Background Myocardial phase velocity mapping studies have generally been acquired using Cartesian k-space coverage and respiratory gating [1,2]. Acquisition durations for high temporal resolution studies are therefore long and unpredictable and the use of navigators and prospective cardiac gating results in ‘dead-times’ in the cardiac cycle where imaging cannot be performed. We have developed a...

BACKGROUND A projection-based method of intrinsic cardiac gating in small-animal computed tomography imaging is presented. METHODS AND RESULTS In this method, which operates without external ECG monitoring, the gating reference signal is derived from the raw data of the computed tomography projections. After filtering, the derived gating reference signal is used to rearrange the projection im...

Introduction: Two-dimensional (2D) breath-hold and ECG-triggered cine MRI is frequently used to assess cardiac function. However this technique requires cooperation from the patient, and the MR acquisition has to be synchronized with the cardiac cycle using ECG. To control respiratory motion, the subject has to perform breath-holds or the position of the diaphragm has to be tracked using a resp...

Respiratory and cardiac motion artefacts degrade image quality in positron emission tomography (PET) imaging and may significantly affect the qualitative and quantitative evaluation of images. At worst, misguided interpretation may lead to wrong diagnosis and inadequate or unnecessary treatment. The aim of this thesis was to study the feasibility of the bioimpedancebased measurement technique f...

Guimaraes et al. (1998) showed that sound-evoked fMRI activation in the auditory midbrain was significantly improved by a method which reduces image signal variability associated with cardiac-related brainstem motion. The method, cardiac gating, synchronizes image acquisition to a constant phase of the cardiac cycle. Since that study, several improvements to auditory fMRI have been made, and it...

UNLABELLED Gating methods acquiring biosignals (such as electrocardiography [ECG] and respiration) during PET enable one to reduce motion effects that potentially lead to image blurring and artifacts. This study evaluated different cardiac and respiratory gating methods: one based on ECG signals for cardiac gating and video signals for respiratory gating; 2 others based on measured inherent lis...

Background Fetal cardiovascular MRI has been hampered by the lack of a reliable cardiac gating signal. A recently proposed solution to this problem is metric optimized gating (MOG) [1-3]. Here, we demonstrate the ability of MOG to acquire images of the fetal myocardium without conventional cardiac gating. Our work is motivated by the need for high-resolution dynamic imaging in the assessment of...

We present an alternative method for evaluating cardiac fat tissue-dual gradient-echo in-phase and opposed-phase magnetic resonance imaging (IPOP-MRI) with electrocardiographic (ECG) gating. Conventional IPOP-MRI can be used to evaluate small amounts of fat and is widely used for abdominal imaging, but cardiac motion artifacts make its use difficult for cardiac imaging. Using ECG gating prior t...