Introduction: Correcting respiratory motion is a challenging task in coronary MRI. Commonly, a pencil-beam right hemi-diaphragm (RHD) navigator is used with a constant 5-7mm gating window (GW) [1]. Data following the navigator signal is only used in image reconstruction if the navigator signal is within the GW otherwise it is reacquired. This usually results in 30%-70% gating efficiency which p...

Respiration-gated radiotherapy for tumor sites affected by respiratory motion will potentially improve radiotherapy outcomes by allowing reduced treatment margins leading to decreased complication rates and/or increased tumor control. Furthermore, for intensity-modulated radiotherapy (IMRT), respiratory gating will minimize the hot and cold spot artifacts in dose distributions that may occur as...

Before treatment delivery of respiratory-gated radiation therapy (RT) in patients with implanted fiducials, both the patient position and the gating window thresholds must be set. In linac-based RT, this is currently done manually and setup accuracy will therefore be dependent on the skill of the user. In this study, we present an automatic method for finding the patient position and the gating...

Techniques have been developed for reducing motion blurring artifacts by using respiratory gated computed tomography (CT) in sinogram space and quantitatively evaluating the artifact reduction. A synthetic sinogram was built from multiple scans intercepting a respiratory gating window. A gated CT image was then reconstructed using the filtered back-projection algorithm. Wedge phantoms, develope...

Introduction Motion artefacts due to respiration or blood flow degrade image quality and limit the acquisition time in human lung MRI. Furthermore, the inherently low proton density as well as rapid signal decay due to the short T2 are challenging. Several techniques have been proposed to avoid respiratory motion artefacts. To synchronise data acquisition with motion, external gating or trigger...

The ability of micro-computed tomography (CT) to noninvasively evaluate allergic pulmonary inflammation in an experimental model was investigated. In addition, two image segmentation methods and the value of respiratory gating were investigated in the context of this model. Brown Norway rats were exposed to one of four doses of house dust mite (HDM) extract (0, 0.15, 15 or 150 microg) delivered...

E. Heijman, W. de Graaf, C. Diekmann, A. Nauerth, G. Strijkers, K. Nicolay Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands, Bruker BioSpin MRI GmbH, Ettlingen, Germany Introduction In cardiac research in vivo studies of mice are indispensable to gain an improved understanding of cardiovascular disease mechanisms and to develop nov...

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...

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 ...

Respiratory motion may cause significant image artefacts in positron emission tomography/computed tomography (PET/CT) imaging. This study introduces a new bioimpedance-based gating method for minimizing respiratory artefacts. The method was studied in 12 oncologic patients by evaluating the following three parameters: maximum metabolic activity of radiopharmaceutical accumulations, the size of ...