Electrocardiographically Gated Thin-Section CT of the Lung1
U. Joseph Schoepf, MD,
Christoph R. Becker, MD,
Roland D. Bruening, MD,
Thomas Helmberger, MD,
Axel Staebler, MD,
Patricia Leimeister, RT and
Maximilian F. Reiser, MD
1 From the Department of Diagnostic Radiology, Klinikum Grosshadern, University of Munich, Marchioninistrasse 15, 81377 Munich, Germany. Received July 20, 1998; revision requested September 3; revision received December 16; accepted April 6, 1999. Address reprint requests to U.J.S. (e-mail: schoepf@ikra.med.uni-muenchen.de).
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Figure 1. Bar graph shows mean scores from three readers for ECG-gated (white bars) and non-ECG-gated (gray bars) thin-section CT studies in 35 patients. Error bars = SD. ECG-gated studies were rated significantly superior to non-ECG-gated studies with regard to pulsation artifacts (P = .022), double images (P = .042), and cardiac delineation (P = .039).
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Figure 2. Bar graph shows mean scores from three readers for ECG-gated (white bars) and non-ECG-gated (gray bars) thin-section CT studies in 16 patients with a heart rate of less than 76 beats per minute. Error bars = SD. In addition to a significant reduction in cardiac motion artifacts, the overall image quality of ECG-gated studies was rated as significantly superior to that of non-ECG-gated studies.
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Figure 3a. (a) Non-ECG-gated and (b) ECG-gated thin-section CT scans in a 35-year-old woman with recurrent pneumothoraces. The "twinkling star" artifact (arrowheads), a motion artifact caused by distortion of pulmonary vessels due to cardiac motion is seen in the lingula of the left upper lobe in a but is less visible in b.
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Figure 3b. (a) Non-ECG-gated and (b) ECG-gated thin-section CT scans in a 35-year-old woman with recurrent pneumothoraces. The "twinkling star" artifact (arrowheads), a motion artifact caused by distortion of pulmonary vessels due to cardiac motion is seen in the lingula of the left upper lobe in a but is less visible in b.
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Figure 4a. (a) Non-ECG-gated and (b) ECG-gated thin-section CT scans in a 62-year-old man with hemoptysis of unknown etiology. Absence of ECG gating can allow cardiac motion to distort pulmonary vessels in the lingula into a U or Y shape and results in focal high-attenuating areas (arrowheads) next to the vessel, as in a. This artifact is sometimes misinterpreted as bronchiectasis and can be prevented by using ECG gating, as in b.
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Figure 4b. (a) Non-ECG-gated and (b) ECG-gated thin-section CT scans in a 62-year-old man with hemoptysis of unknown etiology. Absence of ECG gating can allow cardiac motion to distort pulmonary vessels in the lingula into a U or Y shape and results in focal high-attenuating areas (arrowheads) next to the vessel, as in a. This artifact is sometimes misinterpreted as bronchiectasis and can be prevented by using ECG gating, as in b.
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Figure 5a. (a) Non-ECG-gated and (b) ECG-gated thin-section CT scans obtained at the same level of the paracardiac parenchyma in a 25-year-old man with spontaneous pneumothorax. Note the clear delineation of the left ventricle in b versus the blurred cardiac border (arrow) in a. Both the right and left interlobar fissures (arrowheads) are seen as double lines in a but not in b.
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Figure 5b. (a) Non-ECG-gated and (b) ECG-gated thin-section CT scans obtained at the same level of the paracardiac parenchyma in a 25-year-old man with spontaneous pneumothorax. Note the clear delineation of the left ventricle in b versus the blurred cardiac border (arrow) in a. Both the right and left interlobar fissures (arrowheads) are seen as double lines in a but not in b.
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Figure 6a. (a) Non-ECG-gated and (b) ECG-gated thin-section CT scans obtained at the same level of the paracardiac parenchyma in a 24-year-old man who had undergone lung transplantation. Mild dilatation and bronchial wall thickening in the left lower lobe (white arrows) are better appreciated in b than in a. Also note the blurring of the cardiac border (black arrow) in a.
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Figure 6b. (a) Non-ECG-gated and (b) ECG-gated thin-section CT scans obtained at the same level of the paracardiac parenchyma in a 24-year-old man who had undergone lung transplantation. Mild dilatation and bronchial wall thickening in the left lower lobe (white arrows) are better appreciated in b than in a. Also note the blurring of the cardiac border (black arrow) in a.
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Figure 7a. (a) Non-ECG-gated and (b) ECG-gated thin-section CT scans in a 32-year-old man with fibrotic changes (arrowheads) in the left lower lobe after adult respiratory distress syndrome. The fibrotic areas are subject to cardiac motion in a. The degree of fibrosis and secondary bronchiectasis (arrows) are better appreciated in b than in a.
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Figure 7b. (a) Non-ECG-gated and (b) ECG-gated thin-section CT scans in a 32-year-old man with fibrotic changes (arrowheads) in the left lower lobe after adult respiratory distress syndrome. The fibrotic areas are subject to cardiac motion in a. The degree of fibrosis and secondary bronchiectasis (arrows) are better appreciated in b than in a.
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Figure 8a. (a) Non-ECG-gated and (b) ECG-gated thin-section CT scans obtained at the same level of the paracardiac parenchyma in a 21-year-old woman with cystic fibrosis. Note the clear delineation of dilated bronchi in the lingula of the left upper lobe in b. Cardiac motion results in blurring of the bronchi in a.
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Figure 8b. (a) Non-ECG-gated and (b) ECG-gated thin-section CT scans obtained at the same level of the paracardiac parenchyma in a 21-year-old woman with cystic fibrosis. Note the clear delineation of dilated bronchi in the lingula of the left upper lobe in b. Cardiac motion results in blurring of the bronchi in a.
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Copyright © 1999 by the Radiological Society of North America.
