Diffusion Tensor Magnetic Resonance Imaging Mapping the Fiber Architecture Remodeling in Human Myocardium After Infarction

Wu, Ming Ting; Tseng, Wen‐Yih Isaac; Su, Mao‐Yuan; Liu, Chun Peng; Chiou, Kuan Rau; Wedeen, Van J.; Reese, Timothy G.; Yang, Chun‐Feng

doi:10.1161/circulationaha.105.545863

Cited by 249 publications

(268 citation statements)

References 40 publications

(53 reference statements)

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“…Until now, only two studies have been reported that utilized MR DTI to directly investigate the LV fiber structural changes after infarction (28,30). Chen et al (28) investigated the infarcted region in ex vivo rat hearts with anteroapical infarct 4 weeks after proximal LAD ligation.…”

Section: Discussionmentioning

confidence: 99%

“…The helix angles were calculated pixel by pixel within the slice and their histogram distribution was analyzed using 10°steps. Three groups of fibers were classified based on fiber orientation: left-handed helical fiber (LHF) with helix angle within Ϫ90°to Ϫ30°in epicardium, circumferential fiber (CF) within Ϫ30°to 30°, and right-handed helical fiber (RHF) within 30°to 90°in endocardium (30). Percentages of three groups of fibers were computed in adjacent and remote regions.…”

Section: Mr Data Analysismentioning

confidence: 99%

“…A subsequent ex vivo DTI study of MI in sheep by Walker et al (29) found no apparent change of fiber orientation 16 weeks after anteroapical MI. More recently, in vivo DTI was successfully applied to investigate postinfarct fiber architecture remodeling in humans (30). Significant ADC increase and FA decrease was found in the infarct region, and altered double-helical fiber structure was observed in infarct, adjacent, and remote regions.…”

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MR diffusion tensor imaging study of postinfarct myocardium structural remodeling in a porcine model

Nicholls

et al. 2007

Magnetic Resonance in Med

116

110

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This study aimed to investigate postinfarct left ventricular (LV) fiber structural alterations by ex vivo diffusion tensor imaging (DTI) in a porcine heart model. In vivo cardiac MR imaging was first performed to measure ventricular function in six adult pigs with septal infarction near apex induced by the LAD ligation 13 weeks earlier. Hearts were then excised from the infarct pigs (n ‫؍‬ 6) and six intact controls (n ‫؍‬ 6) and fixed in formalin. High-resolution DTI was employed to examine changes in fractional anisotropy (FA), apparent diffusion coefficient (ADC), and transmural helix angle distribution in the infarct, adjacent and remote regions as compared to the sham regions in the controls. FA values were found to decrease in the infarct and differ between the adjacent and remote regions. ADC increase in the infarct region was substantial, while changes in the adjacent and remote regions were insignificant. Structurally, the doublehelix myocardial structure shifted toward more left-handed around the infarcted myocardium. Accordingly, the histological analysis revealed clear fiber structural degradation in the adjacent region. These findings confirmed the subtle alterations in the myocardial fiber quality and structure not only in the in- Key words: myocardium infarction; borderzone; diffusion tensor imaging; fiber architecture Both structural and functional assessments are important in our understanding of myocardial contraction and relaxation in normal and pathologic states (1,2). It has been long known that left ventricular (LV) myocardial microstructure or fiber structure plays a critical role in determining mechanical properties, such as ventricular torsion, strain, and stress (3,4). Owing to the recent advances in cardiac MR and ultrasound imaging, there is an increasing interest in investigating LV by directly associating the LV myocardial fiber geometry to the complex spatial-temporal sequence of electrical activation and mechanical contraction/relaxation in beating hearts (1,2,5). LV is known to electrically activate first at the exits of Purkinje system, close to apical endocardium. The electrical activation then propagates from apex to base via depolarization and repolarization in both septum and free wall (1,6). This is accompanied by successive mechanical shortenings and intracavitary blood flow along the parallel apex-to-base direction, although highly transient and localized myocardial deformations exist.In infarcted myocardium, remodeling involves both structural and functional changes. Such changes have been found to occur in both infarcted myocardium and adjacent and remote myocardium (7-11). The effects of myocardial infarction (MI) on LV function have been investigated in numerous studies. In recent years, cardiac MR (CMR) imaging has become the accepted reference standard to assess LV function since CMR methods are both accurate and highly reproducible (12). These CMR techniques can be used to detect, localize, and quantify both MI and LV functions. Patten et al. (13) found that hearts...

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Section: Discussionmentioning

confidence: 99%

Section: Mr Data Analysismentioning

confidence: 99%

mentioning

confidence: 99%

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MR diffusion tensor imaging study of postinfarct myocardium structural remodeling in a porcine model

Nicholls

et al. 2007

Magnetic Resonance in Med

116

110

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“…changes at cellular level. As in vivo heart DTI is becoming feasible in humans (30), DTI characterization may lead to new clinical means to assess and monitor the myocardial structure and function in developmental or congenital heart diseases.…”

Section: Discussionmentioning

confidence: 99%

MR study of postnatal development of myocardial structure and left ventricular function

2009

Magnetic Resonance Imaging

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Purpose: To investigate postnatal development of left ventricular (LV) cardiac function and myocardium structure. Materials and Methods:In vivo cardiac MR and ex vivo diffusion tensor imaging (DTI) were performed in normal Sprague-Dawley rats at postnatal day 2, 4, 7, 14, 21, 28, and 56 (N ϭ 6 per group). Results:Morphologically, LV size increased with age. Functionally, stroke volume and cardiac output increased. Heart rate increased gradually and became stable after day 14. On average, ejection fraction increased within the first 4 days, decreased at day 7, gradually increased until day 21, and became stable afterward. Structurally, double-helical myocardial structure was found as early as day 2. Myocardial fiber parameters, described by fractional anisotropy, mean apparent diffusion coefficient, and axial diffusivity, increased within the first 4 days. Then radial diffusivity increased until day 7 while other parameters decreased up to day 56. Conclusion:Postnatal heart development was documented by MRI. DTI findings are in agreement with the two known stages of early postnatal growth: hyperplasia and hypertrophy. These results can serve as the baselines for study of postnatal heart developmental abnormalities. They also demonstrate the ability of DTI to reveal microstructural alterations in myocardium.

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“…Among the possible causes, the differences in the cardiac fiber architecture could be an promising topic. The heart is composed of myocardial fibers organized in a complex laminar structure [18,10], and the cardiac fiber structures have an important role in electrophysiology [8], in mechanical functions [4], and in remodeling [23] of the heart. Changes in the fiber structures are for instance inherent in myocardial hypertrophy [9,19,6].…”

Section: Introductionmentioning

confidence: 99%

Statistical Atlas of Human Cardiac Fibers: Comparison with Abnormal Hearts

Lombaert

Peyrat

Fanton

et al. 2012

Statistical Atlases and Computational Models of the Heart. Imaging and Modelling Challenges

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Abstract. Criteria of normality of the cardiac fibers are important in cardiomyopathies. In this paper, we investigate the differences in the cardiac fiber structures between 10 hearts classified as healthy and 6 hearts classified as abnormal, and determine if properties of the cardiac fiber structures can be discriminants for abnormality. We compare the variability of the fiber directions from abnormal hearts to an atlas of healthy hearts. The human atlas of the cardiac fiber structures is built with an automated framework based on symmetric Log-domain diffeomorphic demons. We study the angular variability of the different fiber structures. Our preliminary results might suggest that a higher variability of the fiber structure directions could possibly characterize abnormality of a heart.

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Diffusion Tensor Magnetic Resonance Imaging Mapping the Fiber Architecture Remodeling in Human Myocardium After Infarction

Cited by 249 publications

References 40 publications

MR diffusion tensor imaging study of postinfarct myocardium structural remodeling in a porcine model

MR diffusion tensor imaging study of postinfarct myocardium structural remodeling in a porcine model

MR study of postnatal development of myocardial structure and left ventricular function

Statistical Atlas of Human Cardiac Fibers: Comparison with Abnormal Hearts

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