Imaging and Quantification of Myocardial Perfusion Using Real-Time Three-Dimensional Echocardiography
Eran Toledo, PhD*,
Roberto M. Lang, MD*,
Keith A. Collins, MS*,
Georgeanne Lammertin, BS*,
Ursula Williams, BS ,
Lynn Weinert, BS*,
Gil Bolotin, MD, PhD,
Patrick D. Coon, BS*,
Jai Raman, MD, PhD,
Lawrence D. Jacobs, MD* and
Victor Mor-Avi, PhD*,*
* Noninvasive Cardiac Imaging Laboratory, University of Chicago, Chicago, Illinois
Section of Cardiothoracic Surgery, University of Chicago, Chicago, Illinois
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Figure 1 Schematic representation of volumetric acquisition in the three protocols: (A) isolated rabbit heart that fits entirely into the pyramidal scan volume; (B) volumetric parasternal short-axis imaging of the pig heart that allows acquisition of the mid portion of the left ventricle; (C) volumetric apical imaging of the human heart that allows acquisition of a partial left ventricular volume that includes mostly the septal and lateral walls.
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Figure 2 Schematic representation of the transient contrast inflow sequence. The upper portion of the diagram shows the time line of imaging steps that comprise the sequence. The bottom portion shows the timing of infusion interruption and resumption (arrows) and their effects on the myocardial contrast with the level of enhancement shown schematically in the shaded band below the time axis. 2D = two-dimensional; MI = mechanical index.
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Figure 3 Three-dimensional rendering of the isolated rabbit heart showing how each dataset was sliced at different levels of the left ventricle (top). At each level, a roughly ring-shaped region of interest (ROI) was defined (top, right) to allow video-intensity measurements in three 3.3-mm-thick slices (middle). The effects of contrast enhancement (CE) on the different slices are shown in the bottom panels.
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Figure 4 (Left) Example of myocardial video-intensity (MVI) time curves obtained from one three-dimensional slice of an isolated rabbit heart at three levels of coronary flow: BL, baseline; F1, 40% to 60% of baseline flow; F2, 10% to 20% of baseline flow. (Right) Average values of myocardial peak contrast inflow rate (PCIR) measured at the different levels of coronary flow (*p < 0.0001 compared with baseline) at each of the three levels of the ventricle.
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Figure 5 (Top left) Dataset that contains the mid portion of the left ventricle, obtained using transthoracic imaging in a pig (anteroseptal region [asp] of interest shown in yellow). Example of en-face short-axis views of a mid-papillary three-dimensional slice obtained at baseline (middle row) and during partial left anterior descending artery occlusion (bottom row) before the onset of (left) and during (center) myocardial contrast inflow, and (right) after reinstatement of steady-state contrast enhancement. (Top right) Regional myocardial video-intensity (MVI) curves obtained in the mid-papillary anteroseptal region of interest: baseline (green) and partial left anterior descending artery occlusion (red). PCIR = peak contrast inflow rate.
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Figure 6 (Left) En-face view of a three-dimensional short-axis slice of a pig heart with the myocardial region of interest divided into six segments. (Right) Regional peak contrast inflow rate (PCIR) (unitless after normalization) calculated from transient contrast inflow (TCI) sequences at baseline, during partial left anterior descending (LAD) artery occlusion, and during reperfusion, averaged over all animals (*p < 0.05 vs. baseline). Different bar colors correspond to specific myocardial segments (left). The two bars of each color represent regions of interest in adjacent slices. Ant = anterior; Asp = anteroseptal; Inf = inferior; Lat = lateral; Pst = posterior; Sep = septal.
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Figure 7 (Top) Near en-face apical four-chamber view of the left ventricle obtained in a normal volunteer at different phases of a transient contrast inflow sequence (left to right). (Bottom left) Corresponding myocardial video-intensity (MVI) curves obtained at rest and during adenosine infusion in one myocardial slice. (Bottom right) Summary of peak contrast inflow rate (peak contrast inflow rate [PCIR], unitless after normalization) measured in three myocardial slices and averaged over all study subjects (*p < 0.01 vs. baseline).
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Figure 8 Pyramidal dataset obtained in a patient with severe discrete left anterior descending artery stenosis (left). A part of the interventricular septum shows clear lack of contrast enhancement, indicating a perfusion defect that was supported by abnormal wall motion. This defect was visible in multiple cross-sections (right), allowing easy estimation of its extent.
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