In vitro proton NMR study of collagen in human aortic wall

Vinée, P; Meurer, B.; Constantinesco, A.; Kohlberger, Bernd; Kh, Hauenstein; Laubenberger, Jörg

doi:10.1002/mrm.1910290303

Cited by 4 publications

(9 citation statements)

References 18 publications

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“…The value found (29") is consistent with results obtained with carbon-13 and deuterium nuclear MR measurements in labeled collagen. Moreover, the fraction MF(0)/M(O) obtained in the aorta ( 12) is consistent with the aortic collagen concentration (as determined with direct destructive chemical measurement) reported by several authors (7.-10), so that one can assume that the fast FID component may be largely assigned to collagen. From the fa:jt FID component, we calculated M2 of the line shape of the collagen macromolecule, as defined by Va.n Vleck ( 18) and extensively described previously (1:2).…”

Section: R Techniquessupporting

confidence: 75%

“…owing to the rapid convergence of the sums; for example, missing a neighboring nucleus farther than 0.5 nm away leads to an error of less than 1%. In the case of mobile rather than rigid groups, a second averaging of the magnetic dipolar interactions is evidenced by a further reduction in experimental Mz (12).…”

Section: R Techniquesmentioning

confidence: 84%

“…The current study of both the MR relaxation characteristics of collagen and collagen content in aneurysm were based on two foundations: ( a ) the ability to access the collagen macromolecular structure with MR spectroscopy (12)(13)(14) and ( b ) the relation between collagen and stress-strain characteristics in the normal aorta ( 16,17). since resistance to rupture is a function of the arrangement and integrity of the tissular protein fibers (10).…”

Section: Discussionmentioning

confidence: 99%

“…Previous investigations (12)(13)(14) In the case of a Gaussian component, T2 provides a measure of M2 (expressed in gauss squared) by M2 is usually used in polymers (19) to characterize the molecular motion that plays an important role in determiming their physical properties, especially their viscoelastic behavior. Van Vleck demonstrated that the theoretical M2 of the line shape of a complex molecule is i t function of the proton-proton distances:…”

Section: R Techniquesmentioning

confidence: 99%

“…They had a frequency of 1.2% in a large autopsy series and are clearly male-dominant lesions, occurring with a male-female ratio of five to one ( 1). They appear at a mean age of 68 years (2).The modifications in the amount and structure of aortic wall collagen in the pathogenesis of aortic aneurysm have been investigated (2-1 1) with various rcsults, from increasing (3,9) to decreasing ( 1 1 ) collagen content or concentration.The analysis of proton nuclear magnetic resonaxice (MR) free induction decay (FID) in collagen of the aortic wall has been recently reported by our group (12)(13)(14), providing a tool for studying collagen content and molecular motion of the collagen macromolecule. Moreover, there is evidence of an important relationship between MR findings and the biomechanical viscoelastic characteristics of the aortic wall (15-17).…”

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confidence: 99%

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MR detection of quantitative and structural changes in human aortic aneurysms

Vinée

Meurer

Constantinesco³

et al. 1993

Magnetic Resonance Imaging

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Collagen is a major component of the extracellular matrix and a determinant of the elastic behavior of the human aorta. To investigate the changes found in aneurysmal degeneration, the authors studied the solid-state hydrogen-1 nuclear magnetic resonance line shape of collagen in aneurysms and normal human aortas. A three-component decomposition of the free induction decay was performed, with collagen characterized by a T2 of about 18 microseconds. The second moment of the collagen line shape was found to be increased in aneurysms (5.3 vs 4.8 G2), while, correspondingly, the T2 of collagen was lower in aneurysms (16.3 vs 17.7 microseconds). This corresponds to a modification of collagen structure and molecular motion. Collagen concentration was lower in nondiseased aortic walls (9.4% vs 7.3%). These results are discussed in reference to the contradictory conclusions in the current literature. The increase in collagen and the modification of its structure and molecular motion are explained by the need to resist an increasing tangential tension due to increased aortic diameter and diminished wall thickness in aneurysms and by intercalation or site binding in the helices or electric dipolar interactions in the less mobile side groups.

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Section: R Techniquessupporting

confidence: 75%

Section: R Techniquesmentioning

confidence: 84%

Section: Discussionmentioning

confidence: 99%

Section: R Techniquesmentioning

confidence: 99%

mentioning

confidence: 99%

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MR detection of quantitative and structural changes in human aortic aneurysms

Vinée

Meurer

Constantinesco³

et al. 1993

Magnetic Resonance Imaging

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Magnetization transfer characteristics in atherosclerotic plaque components assessed by adapted binomial preparation pulses

Pachot‐Clouard

Vaufrey

Darrasse

et al. 1998

MAGMA

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Increasing the contrast between atheromatous plaque components is a major issue in cardiovascular MRI research. It would allow one to identify unstable plaque by differentiating the lipid core associated with vulnerability, from the fibrous cap, considered as a factor of stability. T2 and diffusion-weighted imaging have already provided satisfying results. Magnetization transfer (MT) between restricted protons Hr and free-water protons Hf could achieve a different contrast related to collagen and lipoprotein macromolecules present in the fibrous cap and lipid core, respectively. The purpose of this work was to evaluate in vitro the MT effect produced by adapted T2-selective 1-3-3-1 binomial pulses on isolated samples of atheromatous arteries at 3 T. A method based on simulation was used in order to improve the MT specificity: it is shown that 50% 1-3-3-1 pulses (the percentage indicating the level of Hr saturation) allow an estimation of T2r, the Hr T2. Using this technique, magnetization transfer was observed for the first time in atherosclerotic plaque components, an effect more pronounced for the fibrous cap and media than for the lipid core and adventitia. The T2r estimation gave values ranging from 20 to 25 micros for the four samples. This preliminary study provides a basis for establishing an MT imaging sequence of atheromatous arteries, by using 50% 1-3-3-1 pulses calibrated for saturating protons with a 20 micros T2. This MT protocol should be further compared to T2 and diffusion-weighted imaging.

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