Abstract:
:A magnetic resonance imaging (MRI) method is presented to detect, localize, and quantify myocardial kinematics by measuring the material rate-of-strain tensor at each pixel in gated NMR images of the heart. The immediate, local effect of muscular activity is self-deformation, and the strain tensor is the basic mathematical device by which such deformation may be quantified. The present method, called "strain-phase" MRI (SP-MRI), entails four steps: (1) the velocity of the myocardium is encoded by means of a set of motion-sensitive NMR image acquisitions, one image per velocity component; (2) the spatial derivatives of the velocity are computed at each pixel; (3) the velocity-derivative data are combined to compute an approximation of the strain-rate tensor of the myocardium at each pixel; and (4) the strain-rate tensor data are simplified to produce a color-coded functional image which represents strain-rate components which are of particular biomedical interest in the myocardium. We present a quantitative SP-MRI methodology suited to conventional MRI, and in addition present an "echo-planar" methodology, able to produce qualitative functional images of myocardial kinematics at almost real-time speeds. Two-dimensional strain-phase MRI data acquired in normal human subjects are presented. These data demonstrate the practicability of SP-MRI in vivo, that SP-MRI resolves myocardial kinematics at the single-pixel scale, having resolution comparable to that of conventional MRI, and that SP-MRI data may have a signal-to-noise ratio up to 50% as great as that of the conventional MRI data from which they are produced. SP-MRI measurements of the local instantaneous strain rates in the human left ventricular myocardium are quantitatively consistent with known transmural average values of myocardial strain.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Wedeen VJdoi
10.1002/mrm.1910270107subject
Has Abstractpub_date
1992-09-01 00:00:00pages
52-67issue
1eissn
0740-3194issn
1522-2594journal_volume
27pub_type
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journal_title:Magnetic resonance in medicine
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journal_title:Magnetic resonance in medicine
pub_type: 临床试验,杂志文章,随机对照试验
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更新日期:2013-04-01 00:00:00
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更新日期:2012-11-01 00:00:00
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更新日期:2016-04-01 00:00:00
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更新日期:2014-06-01 00:00:00
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