Cardiovascular magnetic resonance physics for clinicians: part II

Journal of Cardiovascular Magnetic Resonance

Review

John P Ridgway¹  John D Biglands²  Aleksandra Radjenovic³ 

[1] Department of Medical Physics and Engineering, Leeds Teaching Hospitals NHS Trust, 1st Floor, Bexley Wing, St James's University Hospital, LS9 7TF, Leeds, UK;Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, UK;Division of Medical Physics, University of Leeds, Leeds, UK;Department of Medical Physics and Engineering, Leeds Teaching Hospitals NHS Trust, 1st Floor, Bexley Wing, St James's University Hospital, LS9 7TF, Leeds, UK;Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, UK;NIHR-Leeds Musculoskeletal Biomedical Research Unit and Leeds Institute of Molecular Medicine, University of Leeds, Leeds, UK;Multidisciplinary Cardiovascular Research Centre, University of Leeds, Leeds, UK;

关键词: Cardiovascular magnetic resonance;    MR physics;    MR contrast agents;    Fat suppression;    Tagging;    Myocardial perfusion imaging;    Late gadolinium enhancement;    MR angiography;    Velocity mapping;    Myocardial edema;    Myocardial ischemia;    Coronary heart disease;    Myocardial infarction;   

DOI  :  10.1186/1532-429X-14-66

 received in 2012-03-12, accepted in 2012-09-13,  发布年份 2012

来源: Springer

【 摘 要 】

This is the second of two reviews that is intended to cover the essential aspects of cardiovascular magnetic resonance (CMR) physics in a way that is understandable and relevant to clinicians using CMR in their daily practice. Starting with the basic pulse sequences and contrast mechanisms described in part I, it briefly discusses further approaches to accelerate image acquisition. It then continues by showing in detail how the contrast behaviour of black blood fast spin echo and bright blood cine gradient echo techniques can be modified by adding rf preparation pulses to derive a number of more specialised pulse sequences. The simplest examples described include T2-weighted oedema imaging, fat suppression and myocardial tagging cine pulse sequences. Two further important derivatives of the gradient echo pulse sequence, obtained by adding preparation pulses, are used in combination with the administration of a gadolinium-based contrast agent for myocardial perfusion imaging and the assessment of myocardial tissue viability using a late gadolinium enhancement (LGE) technique. These two imaging techniques are discussed in more detail, outlining the basic principles of each pulse sequence, the practical steps required to achieve the best results in a clinical setting and, in the case of perfusion, explaining some of the factors that influence current approaches to perfusion image analysis. The key principles of contrast-enhanced magnetic resonance angiography (CE-MRA) are also explained in detail, especially focusing on timing of the acquisition following contrast agent bolus administration, and current approaches to achieving time resolved MRA. Alternative MRA techniques that do not require the use of an endogenous contrast agent are summarised, and the specialised pulse sequence used to image the coronary arteries, using respiratory navigator gating, is described in detail. The article concludes by explaining the principle behind phase contrast imaging techniques which create images that represent the phase of the MR signal rather than the magnitude. It is shown how this principle can be used to generate velocity maps by designing gradient waveforms that give rise to a relative phase change that is proportional to velocity. Choice of velocity encoding range and key pitfalls in the use of this technique are discussed.

【 授权许可】

Unknown   
© Biglands et al.; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.