Is There a Role For Diffusion Based MRI Sequences in Evaluation and Characterization of Myocardial Infarction?
Mohamed Ali Sayed Amer;
Abstract
Cardiovascular magnetic resonance (CMR) imaging is a great advancement in the field of health care, which has emerged as an important clinical technique in the diagnosis, therapeutics and prognostication of IHD. Early and accurate diagnosis of acute myocardial infarction (MI) is necessary for optimizing management of patients with acute MI and for improving outcome.
Magnetic resonance (CMR) new pulse sequences have got the inherently superior soft tissue contrast provided by MR, so that it now provides the reference standard for in vivo viability imaging as well as the assessment of regional and global systolic function, the detection of myocardial infarction and viability and the evaluation of pericardial disease and cardiac masses.
Evaluation of AMI (acute myocardial infarction) with magnetic resonance imaging, allows detection of reversible and irreversible injury of the myocardium. Cardiovascular Magnetic Resonance (CMR) in one examination provides an accurate assessment of myocardial function and morphology (edema, impaired microcirculation, hemorrhage, and necrosis).
Therefore, CMR has great potential as a diagnostic method in the acute phase of myocardial infarction, providing information on the degree and extent of reversible and irreversible myocardial damage.
STIR sequences are commonly applied to detect myocardial edema, combined with Late Gadolinium Enhancement (LGE); STIR images allow the quantification of myocardial salvage index and to distinguish between acute and chronic injuries.
Despite all the advantages of STIR imaging, this technique has some limitations; the main shortcomings of this technique are motion artifacts, Partial blood suppression in the area of slow flow leading to a “slow flow artifact” which is often confused with sub-endocardial edema. Moreover Dark-blood preparation pulse may also cause a significant signal loss and variations, which may result in an incorrect diagnosis.
Diffusion weighted imaging is a new technique for edema detection in patients with acute myocardial infarction and has higher sensitivity in the detection of myocardial edema than STIR. The sensitivity of the DWI sequence, in contrast to the STIR, does not depend on the infarct location, provides total suppression of the blood signal and reduces the occurrence of motion artifacts. So it may be recommended for the diagnosis of acute injuries, especially in patients with “slow-flow” artifacts in STIR images.
As early and accurate diagnosis of acute myocardial infarction (MI) is necessary for optimizing management of patients with acute MI and for improving outcome. DWI was able to show myocardial involvement in 78% of MI patients in less than 1 min acquisition time, with a similar extent assessment as late-gadolinium enhancement sequence. The most important issue is that MI detection with DWI rose to 97% for recent MIs, despite not discriminating from subacute MIs. The earlier is the MR examination after the cardiac event, the better should be the sensitivity of DWI.
Diffusion tensor magnetic resonance imaging (DT-MRI) has emerged as a candidate method for nondestructive reconstruction of the fiber structure of the left ventricle and reflect the structural integrity of underlying tissues.
It is crucial to investigate the sequential changes of myocardial microstructure and its relationships with changes of macrostructure and function of the left ventricle post-MI; this can be achieved by Diffusion tensor magnetic resonance imaging (DT-MRI).
Magnetic resonance (CMR) new pulse sequences have got the inherently superior soft tissue contrast provided by MR, so that it now provides the reference standard for in vivo viability imaging as well as the assessment of regional and global systolic function, the detection of myocardial infarction and viability and the evaluation of pericardial disease and cardiac masses.
Evaluation of AMI (acute myocardial infarction) with magnetic resonance imaging, allows detection of reversible and irreversible injury of the myocardium. Cardiovascular Magnetic Resonance (CMR) in one examination provides an accurate assessment of myocardial function and morphology (edema, impaired microcirculation, hemorrhage, and necrosis).
Therefore, CMR has great potential as a diagnostic method in the acute phase of myocardial infarction, providing information on the degree and extent of reversible and irreversible myocardial damage.
STIR sequences are commonly applied to detect myocardial edema, combined with Late Gadolinium Enhancement (LGE); STIR images allow the quantification of myocardial salvage index and to distinguish between acute and chronic injuries.
Despite all the advantages of STIR imaging, this technique has some limitations; the main shortcomings of this technique are motion artifacts, Partial blood suppression in the area of slow flow leading to a “slow flow artifact” which is often confused with sub-endocardial edema. Moreover Dark-blood preparation pulse may also cause a significant signal loss and variations, which may result in an incorrect diagnosis.
Diffusion weighted imaging is a new technique for edema detection in patients with acute myocardial infarction and has higher sensitivity in the detection of myocardial edema than STIR. The sensitivity of the DWI sequence, in contrast to the STIR, does not depend on the infarct location, provides total suppression of the blood signal and reduces the occurrence of motion artifacts. So it may be recommended for the diagnosis of acute injuries, especially in patients with “slow-flow” artifacts in STIR images.
As early and accurate diagnosis of acute myocardial infarction (MI) is necessary for optimizing management of patients with acute MI and for improving outcome. DWI was able to show myocardial involvement in 78% of MI patients in less than 1 min acquisition time, with a similar extent assessment as late-gadolinium enhancement sequence. The most important issue is that MI detection with DWI rose to 97% for recent MIs, despite not discriminating from subacute MIs. The earlier is the MR examination after the cardiac event, the better should be the sensitivity of DWI.
Diffusion tensor magnetic resonance imaging (DT-MRI) has emerged as a candidate method for nondestructive reconstruction of the fiber structure of the left ventricle and reflect the structural integrity of underlying tissues.
It is crucial to investigate the sequential changes of myocardial microstructure and its relationships with changes of macrostructure and function of the left ventricle post-MI; this can be achieved by Diffusion tensor magnetic resonance imaging (DT-MRI).
Other data
| Title | Is There a Role For Diffusion Based MRI Sequences in Evaluation and Characterization of Myocardial Infarction? | Other Titles | هل هناك دور لمتواليات التصوير بالرنين المغناطيسي المعتمدة على الانتشار في تقييم وتوصيف احتشاء عضلة القلب؟ | Authors | Mohamed Ali Sayed Amer | Issue Date | 2014 |
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