Pinhole single-photon emission computed tomography for myocardial perfusion imaging of mice
Max C. Wu, PhD*,
Dong-Wei Gao, MD*,
Richard E. Sievers, BS
,
Randall J. Lee, MD, PhD
,
Bruce H. Hasegawa, PhD* and
Michael W. Dae, MD*,*
* Department of Radiology, San Francisco, California, USA
Department of Medicine, San Francisco, California, USA
Cardiovascular Research Institute, University of California San Francisco, San Francisco, California, USA
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Figure 1 System block diagram. Mice are positioned in a plastic tube and rotated in a vertical axis in front of a stationary scintillation camera to acquire tomographic projection images. A personal computer (PC) is used to control both the camera and the rotating stage through the acquisition station and the motor controller.
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Figure 2 Mouse holder. The line source is a circular hole machined into the base of the mouse holder (above the mounting hole) capped by a plastic screw and is colinear to the axis of rotation. After the line source is imaged, the entire assembly is translated vertically to position the mouse in front of the pinhole. As shown in the figure, the mouse’s thorax is within the field of view but the line source is displaced from the field of view when the mouse is imaged. Most of the mouse’s weight is supported by the bottom of the tube and not by the forepaw restraints.
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Figure 3 Short-axis (first two rows), vertical long-axis (third row), and horizontal long-axis (fourth row) slices from a myocardial perfusion study of a control mouse. Image quality is excellent, with the left ventricle well resolved and the right ventricle clearly visible.
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Figure 4 Circumferential profiles for five representative short-axis slices spanning the heart for the control study shown in Figure 3. There is normal variability in the relative image intensity, but no data points fall below 50% of the maximum (for any of the control studies). The anteriolateral reduction in intensity in the apical slice could be the result of apical thinning and the partial volume effect. The threshold for classifying a point as abnormal was set at 50%. Diamonds = apex; squares = apex and midventricular region; triangles = midventricular region; circles = base and midventricular region; rectangles = base.
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Figure 5 Short-axis (first two rows), vertical long-axis (third row), and horizontal long-axis (fourth row) slices from a myocardial perfusion study of a mouse with a left anterior descending coronary artery occlusion at the midventricular level. The image quality is comparable with the example control study (Fig. 3). A large anteriolateral perfusion defect is evident extending from the apex to the midventricular region.
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Figure 6 Circumferential profiles for the study shown in Figure 5. According to the 50% threshold, the apex is entirely involved, but the perfusion defect becomes smaller closer to the base, as is evident in the images. Diamonds = apex; squares = apex and midventricular region; triangles = midventricular region; circles = base and midventricular region; rectangles = base.
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Figure 7 Autoradiographs from the same animal correspond well to the short-axis slices shown in Figure 5.
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Figure 8 Correlation of the measurement of defect size from pinhole single-photon emission computed tomography (SPECT) with autoradiography.
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Copyright © 2003 by the American College of Cardiology Foundation.
