共查询到20条相似文献,搜索用时 0 毫秒
1.
Motion‐corrected simultaneous cardiac positron emission tomography and coronary MR angiography with high acquisition efficiency 下载免费PDF全文
Camila Munoz Radhouene Neji Gastão Cruz Andrew Mallia Sami Jeljeli Andrew J. Reader Rene M. Botnar Claudia Prieto 《Magnetic resonance in medicine》2018,79(1):339-350
2.
3.
Accelerated whole‐heart coronary MRA using motion‐corrected sensitivity encoding with three‐dimensional projection reconstruction 下载免费PDF全文
Jianing Pang Behzad Sharif Reza Arsanjani Xiaoming Bi Zhaoyang Fan Qi Yang Kuncheng Li Daniel S. Berman Debiao Li 《Magnetic resonance in medicine》2015,73(1):284-291
4.
5.
Johannes F. M. Schmidt Martin Buehrer Peter Boesiger Sebastian Kozerke 《Magnetic resonance in medicine》2011,66(6):1541-1549
A nonrigid retrospective respiratory motion correction scheme is presented for whole‐heart coronary imaging with interleaved acquisition of motion information. The quasi‐periodic nature of breathing is exploited to populate a 3D nonrigid motion model from low‐resolution 2D imaging slices acquired interleaved with a segmented 3D whole‐heart coronary scan without imposing scan time penalty. Reconstruction and motion correction are based on inversion of a generalized encoding equation. Therein, a forward model describes the transformation from the motion free image to the motion distorted k‐space data, which includes nonrigid spatial transformations. The effectiveness of the approach is demonstrated on 10 healthy volunteers using free‐breathing coronary whole‐heart scans. Although conventional respiratory‐gated acquisitions with 5‐mm gating window resulted in an average gating efficiency of 51% ± 11%, nonrigid motion correction allowed for gate‐free acquisitions, and hence scan time reduction by a factor of two without significant penalty in image quality. Image scores and quantitative image quality measures for the left coronary arteries showed no significant differences between 5‐mm gated and gate‐free acquisitions with motion correction. For the right coronary artery, slightly reduced image quality in the motion corrected gate‐free scan was observed as a result of the close vicinity of anatomical structures with different motion characteristics. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc. 相似文献
6.
Assessment of cardiac volumes using an isotropic whole‐heart dual cardiac phase sequence in pediatric patients 下载免费PDF全文
Jorge A. Delgado MD Pedro Abad MD Simon Rascovsky MD MSc Victor Calvo BSc Gabriel Castrillon BSc Gerald Greil MD Sergio Uribe PhD 《Journal of magnetic resonance imaging : JMRI》2014,39(3):708-716
7.
8.
9.
10.
11.
12.
Whole‐heart coronary MR angiography using image‐based navigation for the detection of coronary anomalies in adult patients with congenital heart disease 下载免费PDF全文
Markus Henningsson PhD Tarique Hussain MD Miguel S. Vieira MD Gerald F. Greil MD Jouke Smink MSc Gerald v Ensbergen MSc Gabrielle Beck MSc Rene M. Botnar PhD 《Journal of magnetic resonance imaging : JMRI》2016,43(4):947-955
13.
Respiratory motion remains a major challenge for robust coronary MR angiography (MRA). Diaphragmatic navigator (NAV) suffers from indirect measurement of heart position. Respiratory self‐gating (RSG) approaches improve motion detection only in the head–feet direction, leaving motion in the other two dimensions unaccounted for. The purpose of this study was to extend conventional RSG (1D RSG) to RSG capable of 3D motion detection (3D RSG) by acquiring additional RSG projections with transverse‐motion‐encoding gradients. Simulation and volunteer studies were conducted to validate the effectiveness of this new method. Preliminary comparison was performed between coronary artery images reconstructed from the same datasets using different motion correction methods. Our simulation illustrates that a proper motion‐encoding gradient and derivation method enable accurate 3D motion detection. Results from whole‐heart coronary MRA show that 3D RSG can further reduce motion artifacts as compared to NAV and 1D RSG and enables use of larger gating windows for faster coronary imaging. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc. 相似文献
14.
Respiratory self-gated four-dimensional coronary MR angiography: a feasibility study. 总被引:1,自引:0,他引:1
Peng Lai Andrew C Larson Jaeseok Park James C Carr Debiao Li 《Magnetic resonance in medicine》2008,59(6):1378-1385
The four-dimensional (4D) coronary MR angiography (MRA) approach has been developed to eliminate the need for accurate determination of the acquisition window and trigger delay time. Diaphragm navigator (NAV) has been the conventional respiratory gating method for free-breathing coronary MRA. However, NAV echo acquisition interrupts the continuous radiofrequency pulse application required for 4D steady-state free precession coronary MRA. The objective of this work was to investigate the feasibility of a respiratory self-gating (RSG) technique for 4D coronary MRA and its effectiveness by comparing with retrospective NAV gating. Data were acquired continuously throughout the cardiac cycle and retrospectively remapped to cardiac phases based on the electrocardiogram signal simultaneously recorded. An RSG signal extracted from a direct measurement of the heart position was used for retrospective respiratory gating and motion correction. In seven healthy volunteers, 4D MRA images were reconstructed, allowing retrospective assessment of the cardiac motion of the coronary artery and selection of the images with the best vessel delineation. Statistical analysis shows that 4D RSG provides coronary artery delineation comparable to mid-diastole images acquired using NAV. Respiratory self-gating is an effective method for eliminating respiratory motion artifacts and allows 4D coronary MRA during free breathing. 相似文献
15.
Markus Henningsson Peter Koken Christian Stehning Reza Razavi Claudia Prieto René M Botnar 《Magnetic resonance in medicine》2012,67(2):437-445
Several self‐navigation techniques have been proposed to improve respiratory motion compensation in coronary MR angiography. In this work, we implemented a 2D self‐navigation method by using the startup profiles of a whole‐heart balanced Steady‐state free precession sequence, which are primarily used to catalyze the magnetization towards the steady‐state. To create 2D self‐navigation images (2DSN), we added phase encoding gradients to the startup profiles. With this approach we calculated foot–head and left–right motion and performed retrospective translational motion correction. The 2DSN images were reconstructed from 10 startup profiles acquired at the beginning of each shot. Nine healthy subjects were scanned, and the proposed method was compared to a 1D self‐navigation (1DSN) method with foot–head correction only. Foot–head correction was also performed with the diaphragmatic 1D pencil beam navigator (1Dnav) using a tracking factor of 0.6. 2DSN shows improved motion correction compared to 1DSN and 1Dnav for all coronary arteries and all subjects for the investigated diaphragmatic gating window of 10 mm. The visualized vessel length of the right coronary artery could be significantly improved with a multiple targeted 2D self‐navigation approach, compared to 2DSN method. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc. 相似文献
16.
17.
18.
Himanshu Bhat Lan Ge Sonia Nielles‐Vallespin Sven Zuehlsdorff Debiao Li 《Magnetic resonance in medicine》2011,65(5):1269-1277
The navigator gating and slice tracking approach currently used for respiratory motion compensation during free‐breathing coronary magnetic resonance angiography (MRA) has low imaging efficiency (typically 30–50%), resulting in long imaging times. In this work, a novel respiratory motion correction technique with 100% scan efficiency was developed for free‐breathing whole‐heart coronary MRA. The navigator signal was used as a reference respiratory signal to segment the data into six bins. 3D projection reconstruction k‐space sampling was used for data acquisition and enabled reconstruction of low resolution images within each respiratory bin. The motion between bins was estimated by image registration with a 3D affine transform. The data from the different respiratory bins was retrospectively combined after motion correction to produce the final image. The proposed method was compared with a traditional navigator gating approach in nine healthy subjects. The proposed technique acquired whole‐heart coronary MRA with 1.0 mm3 isotropic spatial resolution in a scan time of 6.8 ± 0.9 min, compared with 16.2 ± 2.8 min for the navigator gating approach. The image quality scores, and length, diameter and sharpness of the right coronary artery (RCA), left anterior descending coronary artery (LAD), and left circumflex coronary artery (LCX) were similar for both approaches (P > 0.05 for all), but the proposed technique reduced scan time by a factor of 2.5. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc. 相似文献
19.