Collagen Fiber Morphology Determines Echogenicity of Myocardial Scar: Implications for Image Interpretation

Tabel, Ghasan; Whittaker, Peter; Vlachonassios, Konstantinos; Sonawala, Mehul; Chandraratna, F.R.C.P. P. Anthony

doi:10.1111/j.1540-8175.2006.00178.x

Cited by 16 publications

(8 citation statements)

References 8 publications

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“…20, 21 Carotid artery wall echodensity was assessed within predefined areas of the intima-media, near adventitia, and deep adventitia in 22 HGPS subjects, and compared to 52 age and gender-matched controls (Figure 3A–D). Predefined areas were transformed into histograms representing the spectrum of echobrightness for the entire area captured (Figure 3E–G).…”

Section: Resultsmentioning

confidence: 99%

“…In diseased cardiovascular tissue and plaque, both animal and human studies have supported duplex ultrasound as a useful tool for detecting tissue pathology with dysregulated extracellular matrix through increased echogenicity. When correlating echogenicity with tissue pathology in rats, Tabel et al 20 demonstrated hyperechoic tissue only within older infarcts where thick collagen fibers were present. New infarcts with thinner, normal-looking collagen fibrils were not hyperechoic.…”

Section: Discussionmentioning

confidence: 99%

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Mechanisms of Premature Vascular Aging in Children With Hutchinson-Gilford Progeria Syndrome

et al. 2012

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Hutchinson-Gilford progeria syndrome (HGPS) is a rare, segmental premature aging syndrome of accelerated atherosclerosis and early death from myocardial infarction or stroke. This study sought to establish comprehensive characterization of the fatal vasculopathy in HGPS and its relevance to normal aging. We performed cardiovascular assessments at a single clinical site on the largest prospectively studied cohort to date. Carotid-femoral pulse wave velocity was dramatically elevated (mean 13.00±3.83 m/s). Carotid duplex ultrasound echobrightness, assessed in predefined tissue sites as a measure of arterial wall density, was significantly greater than age- and gender-matched controls in the intima-media (P<0.02), near adventitia (P<0.003) and deep adventitia (P<0.01), as was internal carotid artery mean flow velocity (p<0.0001). Ankle-brachial indices were abnormal in 78% of patients. Effective disease treatments may be heralded by normalizing trends of these noninvasive cardiovascular measures. The data demonstrates that, along with peripheral vascular occlusive disease, accelerated vascular stiffening is an early and pervasive mechanism of vascular disease in HGPS. There is considerable overlap with cardiovascular changes of normal aging, which reinforces the view that defining mechanisms of cardiovascular disease in HGPS provides a unique opportunity to isolate a subset of factors influencing cardiovascular disease in the general aging population.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Mechanisms of Premature Vascular Aging in Children With Hutchinson-Gilford Progeria Syndrome

et al. 2012

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“…Collagen packing can be measured by viewing picosirius red-stained tissue sections under circularly polarized light, under which densely packed collagen fibers are birefringent with a red hue, while loosely packed collagen fibers have a green hue (36,39). Polarized light microscopy of picosirius red-stained sections has been used in a variety of tissues including cardiac muscle (40,44,50,51), but to our knowledge, it has not been applied to skeletal muscle. Thus we sought to investigate how collagen packing is altered in a model of skeletal muscle fibrosis.…”

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confidence: 99%

Collagen content does not alter the passive mechanical properties of fibrotic skeletal muscle in mdx mice

Smith

Barton

2014

American Journal of Physiology-Cell Physiology

113

159

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Many skeletal muscle diseases are associated with progressive fibrosis leading to impaired muscle function. Collagen within the extracellular matrix is the primary structural protein providing a mechanical scaffold for cells within tissues. During fibrosis collagen not only increases in amount but also undergoes posttranslational changes that alter its organization that is thought to contribute to tissue stiffness. Little, however, is known about collagen organization in fibrotic muscle and its consequences for function. To investigate the relationship between collagen content and organization with muscle mechanical properties, we studied mdx mice, a model for Duchenne muscular dystrophy (DMD) that undergoes skeletal muscle fibrosis, and age-matched control mice. We determined collagen content both histologically, with picosirius red staining, and biochemically, with hydroxyproline quantification. Collagen content increased in the mdx soleus and diaphragm muscles, which was exacerbated by age in the diaphragm. Collagen packing density, a parameter of collagen organization, was determined using circularly polarized light microscopy of picosirius red-stained sections. Extensor digitorum longus (EDL) and soleus muscle had proportionally less dense collagen in mdx muscle, while the diaphragm did not change packing density. The mdx muscles had compromised strength as expected, yet only the EDL had a significantly increased elastic stiffness. The EDL and diaphragm had increased dynamic stiffness and a change in relative viscosity. Unexpectedly, passive stiffness did not correlate with collagen content and only weakly correlated with collagen organization. We conclude that muscle fibrosis does not lead to increased passive stiffness and that collagen content is not predictive of muscle stiffness.

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“…The echogenic areas were extracted using a threshold filter of 100 out of a maximal pixel intensity of 255 and subsequently quantified by total area (dermal/perimuscular zone) and by area density (subcutaneous zone). The echogenic bands/areas served as surrogates for collageneous bands since past studies have demonstrated that collagen is hyperechogenic and that these echogenic bands corresponded with histological localization of collagen [25], [26]. To account for slight misplacements of the ultrasound transducer over tested segments, three adjacent images both lateral and medial to the perceived segment image and consecutively spaced 1.6 mm apart were also analyzed and averaged to derive the echogenic content at each segment.…”

Section: Methodsmentioning

confidence: 99%

Electrical Impedance of Acupuncture Meridians: The Relevance of Subcutaneous Collagenous Bands

Ahn

Park²,

Shaw

et al. 2010

PLoS ONE

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BackgroundThe scientific basis for acupuncture meridians is unknown. Past studies have suggested that acupuncture meridians are physiologically characterized by low electrical impedance and anatomically associated with connective tissue planes. We are interested in seeing whether acupuncture meridians are associated with lower electrical impedance and whether ultrasound-derived measures – specifically echogenic collagenous bands - can account for these impedance differences.Methods/ResultsIn 28 healthy subjects, we assessed electrical impedance of skin and underlying subcutaneous connective tissue using a four needle-electrode approach. The impedances were obtained at 10 kHz and 100 kHz frequencies and at three body sites - upper arm (Large Intestine meridian), thigh (Liver), and lower leg (Bladder). Meridian locations were determined by acupuncturists. Ultrasound images were obtained to characterize the anatomical features at each measured site. We found significantly reduced electrical impedance at the Large Intestine meridian compared to adjacent control for both frequencies. No significant decrease in impedance was found at the Liver or Bladder meridian. Greater subcutaneous echogenic densities were significantly associated with reduced impedances in both within-site (meridian vs. adjacent control) and between-site (arm vs. thigh vs. lower leg) analyses. This relationship remained significant in multivariable analyses which also accounted for gender, needle penetration depth, subcutaneous layer thickness, and other ultrasound-derived measures.Conclusion/SignificanceCollagenous bands, represented by increased ultrasound echogenicity, are significantly associated with lower electrical impedance and may account for reduced impedances previously reported at acupuncture meridians. This finding may provide important insights into the nature of acupuncture meridians and the relevance of collagen in bioelectrical measurements.

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Collagen Fiber Morphology Determines Echogenicity of Myocardial Scar: Implications for Image Interpretation

Cited by 16 publications

References 8 publications

Mechanisms of Premature Vascular Aging in Children With Hutchinson-Gilford Progeria Syndrome

Mechanisms of Premature Vascular Aging in Children With Hutchinson-Gilford Progeria Syndrome

Collagen content does not alter the passive mechanical properties of fibrotic skeletal muscle in mdx mice

Electrical Impedance of Acupuncture Meridians: The Relevance of Subcutaneous Collagenous Bands

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