Cyclic variation in ultrasonic myocardial integrated backscatter is due to phasic changes in the number of patent myocardial microvessels

Antonio Micari, Marco Pascotto, Ananda R. Jayaweera, Jiri Sklenar, N. Craig Goodman, Sanjiv Kaul

    Research output: Contribution to journalArticle

    11 Citations (Scopus)

    Abstract

    Objective. We tested the hypothesis that the cyclic variation in ultrasonic myocardial integrated backscatter (IBS) is due to cardiac contraction-induced changes in the number of patent myocardial microvessels. Methods. We performed experiments in open-chest dogs in which we increased the number of patent myocardial microvessels without changing cardiac contraction. We achieved this either by direct intracoronary administration of adenosine (group 1; n = 10) or by producing a noncritical coronary stenosis (group 2; n = 7). Results. At baseline, IBS was lowest in systole and highest in diastole. This cyclic variation in IBS was closely associated with the phasic changes in myocardial blood volume that were measured with myocardial contrast echocardiography During adenosine administration, the diastolic IBS increased from -18.8 ± 6.5 to -17.5 ± 6.1 dB (P = .002), with an associated increase in the difference between the systolic and diastolic IBS from 3.8 ± 1.1 to 4.6 ± 1.0 dB (P = .009). After a non-critical stenosis was produced, diastolic IBS also increased from -26.6 ± 8.3 to -25.2 ±7.3 dB (P = .001), with an associated increase in the difference between the systolic and diastolic IBS from 3.7 ± 1.2 to 5.0 ± 1.0 dB (P = .02). No change in IBS was noted in the bed that did not receive adenosine or the bed that had a stenosis. Conclusions. The variation in IBS during the cardiac cycle is closely associated with the phasic changes in myocardial blood volume seen during cardiac contraction. When the number of patent myocardial arterioles is increased via adenosine or placement of a noncritical stenosis, diastolic IBS increases with a concomitant increase in IBS cyclic variation. These results may have important clinical applications for the noninvasive diagnosis of noncritical coronary stenosis at rest.

    Original languageEnglish (US)
    Pages (from-to)1009-1019
    Number of pages11
    JournalJournal of Ultrasound in Medicine
    Volume25
    Issue number8
    StatePublished - Aug 2006

    Fingerprint

    adenosines
    patents
    Microvessels
    Ultrasonics
    Adenosine
    ultrasonics
    contraction
    blood volume
    Pathologic Constriction
    Coronary Stenosis
    Blood Volume
    beds
    diastole
    systole
    arterioles
    echocardiography
    Diastole
    dogs
    Systole
    chest

    Keywords

    • Cardiac contraction
    • Cyclic variation
    • Integrated backscatter
    • Myocardial blood volume

    ASJC Scopus subject areas

    • Radiology Nuclear Medicine and imaging
    • Radiological and Ultrasound Technology
    • Acoustics and Ultrasonics

    Cite this

    Cyclic variation in ultrasonic myocardial integrated backscatter is due to phasic changes in the number of patent myocardial microvessels. / Micari, Antonio; Pascotto, Marco; Jayaweera, Ananda R.; Sklenar, Jiri; Goodman, N. Craig; Kaul, Sanjiv.

    In: Journal of Ultrasound in Medicine, Vol. 25, No. 8, 08.2006, p. 1009-1019.

    Research output: Contribution to journalArticle

    Micari, Antonio ; Pascotto, Marco ; Jayaweera, Ananda R. ; Sklenar, Jiri ; Goodman, N. Craig ; Kaul, Sanjiv. / Cyclic variation in ultrasonic myocardial integrated backscatter is due to phasic changes in the number of patent myocardial microvessels. In: Journal of Ultrasound in Medicine. 2006 ; Vol. 25, No. 8. pp. 1009-1019.
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    abstract = "Objective. We tested the hypothesis that the cyclic variation in ultrasonic myocardial integrated backscatter (IBS) is due to cardiac contraction-induced changes in the number of patent myocardial microvessels. Methods. We performed experiments in open-chest dogs in which we increased the number of patent myocardial microvessels without changing cardiac contraction. We achieved this either by direct intracoronary administration of adenosine (group 1; n = 10) or by producing a noncritical coronary stenosis (group 2; n = 7). Results. At baseline, IBS was lowest in systole and highest in diastole. This cyclic variation in IBS was closely associated with the phasic changes in myocardial blood volume that were measured with myocardial contrast echocardiography During adenosine administration, the diastolic IBS increased from -18.8 ± 6.5 to -17.5 ± 6.1 dB (P = .002), with an associated increase in the difference between the systolic and diastolic IBS from 3.8 ± 1.1 to 4.6 ± 1.0 dB (P = .009). After a non-critical stenosis was produced, diastolic IBS also increased from -26.6 ± 8.3 to -25.2 ±7.3 dB (P = .001), with an associated increase in the difference between the systolic and diastolic IBS from 3.7 ± 1.2 to 5.0 ± 1.0 dB (P = .02). No change in IBS was noted in the bed that did not receive adenosine or the bed that had a stenosis. Conclusions. The variation in IBS during the cardiac cycle is closely associated with the phasic changes in myocardial blood volume seen during cardiac contraction. When the number of patent myocardial arterioles is increased via adenosine or placement of a noncritical stenosis, diastolic IBS increases with a concomitant increase in IBS cyclic variation. These results may have important clinical applications for the noninvasive diagnosis of noncritical coronary stenosis at rest.",
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    T1 - Cyclic variation in ultrasonic myocardial integrated backscatter is due to phasic changes in the number of patent myocardial microvessels

    AU - Micari, Antonio

    AU - Pascotto, Marco

    AU - Jayaweera, Ananda R.

    AU - Sklenar, Jiri

    AU - Goodman, N. Craig

    AU - Kaul, Sanjiv

    PY - 2006/8

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    N2 - Objective. We tested the hypothesis that the cyclic variation in ultrasonic myocardial integrated backscatter (IBS) is due to cardiac contraction-induced changes in the number of patent myocardial microvessels. Methods. We performed experiments in open-chest dogs in which we increased the number of patent myocardial microvessels without changing cardiac contraction. We achieved this either by direct intracoronary administration of adenosine (group 1; n = 10) or by producing a noncritical coronary stenosis (group 2; n = 7). Results. At baseline, IBS was lowest in systole and highest in diastole. This cyclic variation in IBS was closely associated with the phasic changes in myocardial blood volume that were measured with myocardial contrast echocardiography During adenosine administration, the diastolic IBS increased from -18.8 ± 6.5 to -17.5 ± 6.1 dB (P = .002), with an associated increase in the difference between the systolic and diastolic IBS from 3.8 ± 1.1 to 4.6 ± 1.0 dB (P = .009). After a non-critical stenosis was produced, diastolic IBS also increased from -26.6 ± 8.3 to -25.2 ±7.3 dB (P = .001), with an associated increase in the difference between the systolic and diastolic IBS from 3.7 ± 1.2 to 5.0 ± 1.0 dB (P = .02). No change in IBS was noted in the bed that did not receive adenosine or the bed that had a stenosis. Conclusions. The variation in IBS during the cardiac cycle is closely associated with the phasic changes in myocardial blood volume seen during cardiac contraction. When the number of patent myocardial arterioles is increased via adenosine or placement of a noncritical stenosis, diastolic IBS increases with a concomitant increase in IBS cyclic variation. These results may have important clinical applications for the noninvasive diagnosis of noncritical coronary stenosis at rest.

    AB - Objective. We tested the hypothesis that the cyclic variation in ultrasonic myocardial integrated backscatter (IBS) is due to cardiac contraction-induced changes in the number of patent myocardial microvessels. Methods. We performed experiments in open-chest dogs in which we increased the number of patent myocardial microvessels without changing cardiac contraction. We achieved this either by direct intracoronary administration of adenosine (group 1; n = 10) or by producing a noncritical coronary stenosis (group 2; n = 7). Results. At baseline, IBS was lowest in systole and highest in diastole. This cyclic variation in IBS was closely associated with the phasic changes in myocardial blood volume that were measured with myocardial contrast echocardiography During adenosine administration, the diastolic IBS increased from -18.8 ± 6.5 to -17.5 ± 6.1 dB (P = .002), with an associated increase in the difference between the systolic and diastolic IBS from 3.8 ± 1.1 to 4.6 ± 1.0 dB (P = .009). After a non-critical stenosis was produced, diastolic IBS also increased from -26.6 ± 8.3 to -25.2 ±7.3 dB (P = .001), with an associated increase in the difference between the systolic and diastolic IBS from 3.7 ± 1.2 to 5.0 ± 1.0 dB (P = .02). No change in IBS was noted in the bed that did not receive adenosine or the bed that had a stenosis. Conclusions. The variation in IBS during the cardiac cycle is closely associated with the phasic changes in myocardial blood volume seen during cardiac contraction. When the number of patent myocardial arterioles is increased via adenosine or placement of a noncritical stenosis, diastolic IBS increases with a concomitant increase in IBS cyclic variation. These results may have important clinical applications for the noninvasive diagnosis of noncritical coronary stenosis at rest.

    KW - Cardiac contraction

    KW - Cyclic variation

    KW - Integrated backscatter

    KW - Myocardial blood volume

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