Basis for detection of stenosis using venous administration of microbubbles during myocardial contrast echocardiography: bolus or continuous infusion?
Kevin Wei, MD, FACCa,
Ananda R. Jayaweera, PhDa,
Soroosh Firoozan, MDa,
Andre Linka, MDa,
Danny M. Skyba, PhDa and
Sanjiv Kaul, MD, FACCa
a Cardiovascular Division, University of Virginia School of Medicine, Charlottesville, Virginia, USA
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Figure 1 Color-coded images and corresponding time–intensity plots (fitted to a gamma-variate function) in a Group I dog during hyperemia. At baseline (A), there is no difference in VI between the LAD and LCx beds. In the presence of a mild stenosis (transstenotic pressure gradient 14 mm Hg), VI in the LAD bed decreased compared with that in the LCx bed (B). The decrease was even greater (C) in the presence of a moderate stenosis (transstenotic pressure gradient 22 mm Hg). Open squares = LAD bed; solid squares = LCx bed.
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Figure 2 Relation between MBF ratio (x axis) and VI ratio (y axis) obtained from the stenosed versus the normal bed in Group I dogs during hyperemia.
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Figure 3 Color-coded images and corresponding time–intensity plots (fitted to a gamma-variate function) in a Group II dog receiving a bolus injection of contrast during hyperemia. At baseline (A), there is no difference in VI between the LAD and LCx beds. In the presence of a mild stenosis (pressure gradient 13 mm Hg), VI in the LAD bed is less than that in the LCx bed (B). Arrows indicate the region in the LCx bed from which the time–intensity curves were derived; other symbols as in Figure 1.
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Figure 4 Color-coded images and the corresponding VI versus PI curves at baseline (A) and in the presence of a LAD stenosis (B) during continuous infusion in the same Group II dog as in Figure 3. The images correspond to the point in the curves where maximal contrast disparity between the stenosed and normal beds was seen. Symbols as in Figure 3.
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Figure 5 A, Relation between radiolabeled microsphere-derived MBF ratio (x axis) and MCE-derived MBF (A·B ratio) from the stenosed versus normal bed in all Group II dogs during hyperemia (y axis). B, Relation between peak VI ratio during bolus injection (x axis) and plateau VI ratio during continuous infusion (y axis) from the stenosed versus normal bed in all Group II dogs.
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Figure 6 Color-coded images during continuous infusion in a Group II dog (A to C) with a mild stenosis at three different PIs. The image showing the maximal VI difference between the stenosed (LAD) and normal (LCx) beds (B) was selected from the VI versus PI curve (D). This image best represents the presence and severity of stenosis. Symbols as in Figure 1.
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