Multidetector Computed Tomography Myocardial Perfusion Imaging During Adenosine Stress
Richard T. George, MD*,
Caterina Silva, MD*,
Marco A.S. Cordeiro, MD, PhD*,
Anthony DiPaula, BS*,
Douglas R. Thompson, PhD||,
William F. McCarthy, PhD||,
Takashi Ichihara, PhD¶,
Joao A.C. Lima, MD, FACC*, and
Albert C. Lardo, PhD, FAHA*, , ,,*
* Department of Medicine, Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland
Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
|| Maryland Medical Research Institute, Baltimore, Maryland
¶ Toshiba Medical Systems Corporation, Otawara, Japan.
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Figure 1 Experimental protocol for multidetector computed tomography (MDCT) myocardial perfusion imaging.
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Figure 2 Mid-ventricular slice in the axial plane showing a perfusion deficit (arrows) in the anteroseptal, anterior, and anterolateral myocardial territory supplied by the stenosed left anterior descending artery (left). Multiplanar reconstruction showing the extent of the perfusion deficit (arrows) extending from the anteroseptal and anterior walls to the apex (right).
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Figure 3 Differences in myocardial signal density measured in myocardial territories supplied by a stenosed left anterior descending coronary artery (open bars) versus remote territories (solid bars) in experiments 1 through 6 receiving adenosine (p < 0.05). No significant difference noted in the control.
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Figure 4 (A) Shows a mid-ventricular slice of myocardium clearly showing remote territories stained with Monastral blue dye and the unstained left anterior descending coronary artery territory. (B) Shows the corresponding multiplanar reconstructed image in short axis. Using semiautomated function/perfusion software (Toshiba, Inc.), myocardium meeting the perfusion deficit signal density threshold of one standard deviation below the remote myocardial signal density is designated in blue.
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Figure 5 Perfusion deficit myocardial signal density (SD) divided by the left ventricular (LV) blood pool signal density (y-axis) versus microsphere-derived myocardial blood flow (x-axis) in the stenosed left anterior descending artery territory determined by a semiautomated approach that defines the perfusion deficit as one standard deviation below the mean SD of the remote myocardial territory. (y = 0.07037x – 0.00681, Pearson R = 0.98, p < 0.001; LR chi-square [1 degree of freedom] = 19.21, SE = 0.007, p < 0.0001) (n = 6).
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Figure 6 (A) Regional myocardial signal density divided by the left ventricular blood pool signal density (y-axis) versus microsphere-derived myocardial blood flow (x-axis) in both the stenosed left anterior descending artery territory and remote myocardial territory using a semiautomated volumetric analysis over the range of flows studied (y = –0.00168x2 + 0.04701x + 0.07604, LR chi-square (2 df) = 31.8, p < 0.0001). (B) Data representing flows less than 8 ml/g/min from (A) are shown in (B) (y = 0.03453x + 0.09437, LR chi-square [1 degree of freedom] = 17.0, SE = 0.007, p < 0.0001) (n = 7). SD ratio = myocardial signal density/left ventricular blood pool signal density.
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Figure 7 Slice-by-slice myocardial signal density divided by the left ventricular blood pool signal density (y-axis) versus slice-by-slice microsphere-derived myocardial blood flow (x-axis) in both the stenosed left anterior descending artery territory and remote myocardial territory over the range of flows studied (y = –0.00041x2 + 0.01575x + 0.1937 LR chi-square [2 degrees of freedom] = 14.1, p = 0.001) (n = 163). SD ratio = myocardial signal density/left ventricular blood pool signal density.
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Figure 8 Signal density-time curves in a canine model of left anterior descending artery stenosis during infusion of adenosine, intravenous iodinated contrast (2.5 ml/s), and dynamic multidetector computed tomography scanning. Myocardial curves were measured from the anterior myocardial wall (stenosed) and the inferior myocardial wall (remote). Vertical lines illustrate the period that helical multidetector computed tomography scanning took place during this study. Helical scanning was triggered when bolus tracking detected a signal density of 180 HU in the ascending aorta. LV = left ventricle.
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Figure 9 First-pass, adenosine-augmented multidetector computed tomography (MDCT) myocardial perfusion imaging in a patient referred for invasive angiography after single-photon emission computed tomography showed a fixed perfusion deficit in the inferior and inferolateral territories. Panels A and C demonstrate an inferior and inferolateral subendocardial perfusion deficit in the mid and distal left ventricle, respectively (arrows). Using semi-automated function/perfusion software, myocardium meeting the perfusion deficit signal density threshold of one standard deviation below the remote myocardial signal density is designated in blue in panels B and D. Invasive angiography shows a chronically occluded distal right coronary artery with left to right collaterals filling the posterior descending (arrows) and posterolateral branches (E). (F) 17-segment polar plot of MDCT-derived myocardial signal densities. Note the hypoperfused inferior and inferolateral regions displayed in blue.
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