HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Figures Only Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Schoepf, U. J. Articles by Reiser, M. F. Search for Related Content PubMed PubMed Citation Articles by Schoepf, U. J. Articles by Reiser, M. F.

Electrocardiographically Gated Thin-Section CT of the Lung¹

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).

	Abstract

TOP Abstract Introduction MATERIALS AND METHODS RESULTS DISCUSSION References

 
PURPOSE: To determine whether electrocardiographic (ECG) gating improves image quality of thin-section computed tomographic (CT) scans of the lung obtained with a subsecond CT scanner.

MATERIALS AND METHODS: Thin-section CT was performed in 35 patients by using standard techniques. Three additional sections were obtained in each patient with prospective ECG gating at corresponding levels of the paracardiac lung parenchyma. Non–ECG-gated and ECG-gated sections were then rated in blinded fashion by three experienced radiologists for overall image quality, spatial resolution, and diagnostic value and for different types of respiratory and cardiac motion artifacts.

RESULTS: ECG gating helped significantly reduce artifacts caused by cardiac motion (ie, distortion of pulmonary vessels, double images, or blurring of the cardiac border) (P < .05). ECG gating did not reduce respiratory motion artifacts. In patients with heart rates of less than 76 beats per minute, ECG gating significantly improved overall image quality (P = .041). ECG gating was not perceived to increase the diagnostic value of thin-section CT scans.

CONCLUSION: ECG gating improves image quality of thin-section CT scans of the lung by reducing cardiac motion artifacts that may mimic disease. It must be established whether ECG gating can help increase the diagnostic accuracy of thin-section CT for the evaluation of subtle parenchymal disease.

Index terms: Computed tomography (CT), technology, 60.12118 • Computed tomography (CT), thin-section, 60.12118 • Emphysema, 60.751 • Fibrosis, cystic, 60.252 • Lung, CT, 60.12111, 60.12118 • Lung, infection, 60.2028. 60.2056, 60.2066, 60.213 • Pneumonia, usual interstitial, 60.213

	Introduction

TOP Abstract Introduction MATERIALS AND METHODS RESULTS DISCUSSION References

 
Thin-section computed tomography (CT) of the lung has become accepted as the method of choice for accurate demonstration of the pulmonary parenchyma. It has found widespread use in a number of clinical settings, including the assessment of interstitial pneumonitis, pulmonary fibrosis, emphysema, or bronchiectasis (1–6).

The quality of thin-section CT images, however, often is compromised because of respiratory or cardiac motion artifacts (6–9). Some of these artifacts mimic pathologic conditions and thus constitute a potential pitfall in the diagnosis of interstitial or bronchial disease (6,9–12). Whereas gross respiratory motion causes general blurring of the image, subtle movements due to transmitted cardiac pulsations may result in double images of pulmonary vessels (11) or fissures (12,13). The resultant double lines can be mistaken for the "tram-line" appearance of thickened bronchial walls (1,11). Curvilinear distortion of pulmonary vessels by means of cardiac movement results in a focal area of low attenuation adjacent to the vessel. This artifact may mimic the cystic appearance of bronchiectasis (7,9–11).

Despite of the advent of fast CT image acquisition techniques, these artifacts can still be observed with disturbing frequency (8,14). For effective suppression of motion artifacts on CT images, scanning times of less than 19.1 msec would be necessary (14). Even with increasingly faster CT technology, scanning times this short will not be accomplished in the near future.

Another potential way to reduce cardiac motion artifacts is to acquire images during the diastole of the cardiac cycle, when ventricular movement is at its minimum. Effective electrocardiographic (ECG) gating has so far been limited to use in electron-beam CT (15,16). However, prospective ECG gating, which allows the triggered acquisition of scans at a predefined interval after the R wave of the electrocardiogram, has recently become commercially available for sequential scanning with conventional spiral CT systems (17). We performed a prospective study to determine whether transmitted cardiac motion artifacts are amenable to a CT protocol that involves prospective ECG gating with a subsecond CT scanner.

	MATERIALS AND METHODS

TOP Abstract Introduction MATERIALS AND METHODS RESULTS DISCUSSION References

 
Study Design
Sequential thin-section CT studies were obtained in 35 consecutive patients (21 men, 14 women; aged 19–68 years; mean age, 38 years) suspected of having a disease of the pulmonary parenchyma. CT studies were acquired by using a routine technique, as recommended by the manufacturer, and an alternative protocol that involved prospective ECG gating of scans. Double radiation exposure to the patient for the evaluation of prospective ECG gating at conventional CT was not considered to require approval by our internal review board, because the additional radiation dose did not exceed an effective dose of 0.86 mSv. Informed consent was obtained from each patient.

Indications for performance of thin-section CT in our patient population were pulmonary emphysema (n = 5), ambiguous findings on chest radiographs in healthy individuals (n = 4), aspergillosis after bone marrow transplantation (n = 4), evaluation for lung transplantation (n = 3), spontaneous pneumothorax (n = 3), usual interstitial pneumonitis (n = 2), cytomegalovirus infection after bone marrow transplantation (n = 2), cystic fibrosis (n = 2), interstitial pneumonia (n = 2), possible legionellosis after adult respiratory distress syndrome (n = 1), lymphangioleiomyomatosis (n = 1), allergic alveolitis (n = 1), hemoptysis (n = 1), drug-induced pulmonary fibrosis (n = 1), 1-antitrypsin deficiency (n = 1), graft rejection after lung transplantation (n = 1), and bronchiectasis after lung transplantation (n = 1).

Scanning Technique
Scanning was performed with a subsecond helical CT scanner (Somatom Plus 4A; Siemens Medical Systems, Erlangen, Germany), which is capable of prospective ECG-gating. In this setting, the ECG signal is detected by means of three ECG leads placed on the patient and an ECG monitor connected to the CT system. An update of the scanner software allowed identification of the R wave. Each scan acquisition was initiated by means of a trigger signal sent to the scanner after an operator-selected delay measured from the peak of the R wave. The ECG monitor was permanently connected to the scanner, and the ECG-gating protocol was stored in the protocol menu. Performance of ECG-gated versus non–ECG-gated CT, therefore, required an additional investment of less than 2 minutes to attach ECG electrodes to the patient.

By using this approach, a cluster of three ECG-gated scans with a 20-mm scan interval was acquired in each patient at three levels in the epiphrenic, paracardiac lung parenchyma. Pilot study results (not shown) had demonstrated that optimal image acquisition during the diastole of the heart can be achieved when scanning is initiated at 50% of the R-R interval. Therefore, scan acquisition was gated at this trigger interval by using 1-mm collimation at 120 kV, 170 mA, and 500 msec per 240° rotation (0.75 second per 360° rotation). To prevent artifacts from an insufficient number of projections acquired during the 500-msec scan acquisition time, images were reconstructed with a high-spatial-frequency algorithm ("AB82" [10.9 line pairs per centimeter at 2% modulation transfer function]; Siemens Medical Systems) instead of the very-high-frequency algorithm that was used for the standard technique.

On completion, each patient underwent scanning craniocaudally from the apex of the lung to the diaphragm by using two to three clusters of non–ECG-gated acquisitions with a scan interval of 10 mm and the standard thin-section CT techniques recommended by the manufacturer. One-millimeter collimation was again used at 120 kV, 90 mA, and 1,500-msec exposure per 360° rotation. Each cluster was acquired during one breath hold. Images were reconstructed by using a very-high-spatial-frequency algorithm ("AB91" [12.42 line pairs per centimeter at 2% modulation transfer function]; Siemens Medical Systems). The heart rate in each patient was documented.

Image Analysis
For each patient, the three ECG-gated scans were displayed at lung window settings (level, -400 HU; width, 1,400 HU) and were printed in four-on-one format without text. From the non–ECG-gated studies, the three scans of the paracardiac parenchyma that were acquired at levels closest to the table positions of the ECG-gated scans were chosen for comparison and were printed in the same manner as the ECG-gated scans.

The printed scans were presented in random order to three experienced radiologists (R.D.B., T.H., A.S.) in a way that did not allow direct comparison of ECG-gated and non–ECG-gated scans in an individual patient. Each reader reviewed the images individually and was blinded to the scanning technique. Studies were rated for general impression, spatial resolution, overall diagnostic value, and motion artifacts, by using a three-point scale, where the "best" value was 3. The criteria for motion artifacts included (a) double-imaged lung structures (bronchial walls, vessels, fissures), (b) doubling and blurring of the cardiac border, (c) pulsation artifacts attributable to cardiac motion (ie, distortion of vessels resulting in "star" artifacts or low-attenuating areas adjacent to the vessel), and (d) respiratory artifacts.

Statistical Analyses
Statistical analyses were performed by using commercially available software (STATVIEW; Abacus Concepts, Berkeley, Calif). For each criterion and for each of the 35 patients, mean scores of the three readers were calculated for ECG-gated and non–ECG-gated studies and were tested to determine whether the scores were normally distributed. Mean scores were then tested for differences by using the paired Student t test. A P value of less than .05 was regarded as indicative of a statistically significant difference. Interobserver agreement was determined on the basis of total score values for all categories in each patient by calculating the product-moment correlation coefficient.

	RESULTS

TOP Abstract Introduction MATERIALS AND METHODS RESULTS DISCUSSION References

 
A total of 210 images were evaluated (two sets of three images each in 35 patients) by all three readers. The mean heart rate (± SD) was 80.5 beats per minute ± 12.0; 16 patients had a heart rate of 76 beats per minute or slower (mean, 71.5 beats per minute), and 19 had a heart rate faster than 76 beats per minute (mean, 88 beats per minute).

When all patients were considered, significant differences between ECG-gated and non–ECG-gated images were found for the presence of pulsation artifacts (P = .022) and double images (P = .042) and for delineation of the heart (P = .039). For these categories, the readers considered ECG-gated studies to be superior to non–ECG-gated studies (Fig 1). No differences between the two techniques were found for overall image quality, spatial resolution, diagnostic value, and respiratory artifacts (P > .05 for all).

View larger version (24K): [in this window] [in a new window]   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).

View larger version (23K): [in this window] [in a new window]   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.

	DISCUSSION

TOP Abstract Introduction MATERIALS AND METHODS RESULTS DISCUSSION References

 
Thin-section CT is the method of choice for evaluation of the pulmonary parenchyma (6,18,19). The image quality of thin-section CT scans of the lung, however, is frequently degraded due to a variety of artifacts that can be confusing to an observer who is not familiar with them.

Fine streak artifacts radiating from bone, referred to as aliasing or correlated noise, are more evident on thin-section studies than on conventional studies (7). Motion artifacts can arise from respiratory motion or from transmitted cardiac pulsations (6,7,9): Gross motion results in general blurring of the image and can render single sections or an entire study nondiagnostic; slight motion, however, may result in artifacts that have long been recognized to mimic pathologic conditions. These artifacts are usually caused by transmitted cardiac pulsation and include curvilinear distortion of pulmonary vessels resulting in "starlike" streaks that radiate from the vessel, with focal low-attenuating areas between the streaks (Figs 3,4) (6,9–11). The low-attenuating areas, in particular, may be misinterpreted as dilated bronchi (Fig 4) (6,9,10). In addition, vessels, bronchi, and fissures in the vicinity of the heart may be in slightly different positions over the course of the study, which could result in double images on the reconstructed section (Fig 5) and thus mimic bronchiectasis (6,11,12).

View larger version (144K): [in this window] [in a new window]   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.

View larger version (156K): [in this window] [in a new window]   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.

View larger version (129K): [in this window] [in a new window]   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.

View larger version (126K): [in this window] [in a new window]   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.

View larger version (153K): [in this window] [in a new window]   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.

View larger version (147K): [in this window] [in a new window]   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.

Our results suggest that, besides the anticipated applications in cardiovascular CT (17), ECG gating may also prove to be beneficial in reducing cardiac motion artifacts at thin-section CT of the lung. ECG gating significantly reduced the types of artifact (distortion of pulmonary vessels, double images) that may be mistaken for disease by an observer who is less familiar with thin-section CT (Fig 1).

The ECG-gating protocol was better for reducing cardiac motion artifacts and improving overall image quality in patients with a slower heart rate than in those with a faster heart rate (Fig 2). In these patients, the scores for most criteria were higher than those in the total population, most likely because individuals with a normal heart rate usually are in less distress than patients experiencing tachycardia. More important, however, ECG gating partially loses its effectiveness when the heart rate is faster than 75–80 beats per minute, because the diastole of the heart becomes too short for a 500-msec data acquisition.

Although a scan acquisition time of 500 msec allows image acquisition during the diastole in patients with a normal heart rate, it does not generate the necessary number of projections for image reconstruction with a very-high-spatial-frequency algorithm. Reconstruction with a very-high-spatial-frequency algorithm still requires a 1,500-msec rotation for acquisition of a sufficient number of projections. However, effective reduction of cardiac motion artifacts cannot be achieved by using standard scanning times, which are longer than the diastole. To restrict image acquisition to the diastole, scanning time had to be decreased to 500 msec for ECG-gated acquisitions. To prevent artifacts because of an insufficient number of projections, we chose an algorithm with a somewhat lower spatial frequency for reconstruction with ECG-gated scans. This, however, evidently did not affect the quality of ECG-gated images as compared with that of non–ECG-gated images, which had been acquired during a 1,500-msec rotation (Figs 1, 2).

A possible limitation of our study that must be considered was that the influence of a 500-msec acquisition time without the use of ECG gating was not investigated. If the improvement in image quality was caused by the shorter acquisition time alone, however, differences in heart rate should not have influenced the results, and a reduction in the occurrence and severity of respiratory artifacts would also have been expected. Because this was not the case, ECG gating probably was the larger contributor to the improvement in image quality.

Differences between images obtained with ECG gating and those obtained without ECG gating might have been less pronounced had studies of the entire chest been considered. However, to evaluate the potential benefit of ECG gating, we intentionally focused on the paracardiac lung segments, because these regions are most likely to be subject to transmitted cardiac motion.

Three experienced interpreters of thin-section CT scans at our department volunteered as readers for this study. For these readers, ECG gating did not improve the diagnostic value of thin-section CT scans. This may partially result from the familiarity of these observers with the different types of artifacts that can degrade thin-section CT scans. It must be established whether ECG gating can help improve the diagnostic accuracy of thin-section CT for physicians who are less aware of diagnostic pitfalls. Furthermore, subtle and incipient changes in the parenchyma may be diagnosed earlier and more confidently on studies that are less subject to motion artifacts (Figs 6–8). Finally, ECG-gated CT with a variety of applications is likely to become more beneficial in a larger patient population with the advent of conventional CT scanners capable of even shorter scanning times.

View larger version (222K): [in this window] [in a new window]   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.

View larger version (210K): [in this window] [in a new window]   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.

View larger version (169K): [in this window] [in a new window]   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.

View larger version (173K): [in this window] [in a new window]   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.

View larger version (145K): [in this window] [in a new window]   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.

View larger version (148K): [in this window] [in a new window]   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.

	Footnotes

 
Abbreviation: ECG = electrocardiographic

Author contributions: Guarantors of integrity of entire study, U.J.S., M.F.R.; study concepts, U.J.S.; study design, U.J.S., C.R.B.; definition of intellectual content, U.J.S., C.R.B., M.F.R.; literature research, U.J.S., C.R.B.; clinical studies, U.J.S., C.R.B., R.D.B., P.L.; data acquisition, U.J.S., C.R.B., P.L.; data analysis, U.J.S., R.D.B., T.H., A.S.; statistical analysis, U.J.S.; manuscript preparation and editing, U.J.S.; manuscript review, C.R.B., R.D.B., T.H., A.S., M.F.R.

	References

TOP Abstract Introduction MATERIALS AND METHODS RESULTS DISCUSSION References

 

1. Naidich DP, McCauley DI, Khouri NF, Stitik FP, Siegelman SS. Computed tomography of bronchiectasis. J Comput Assist Tomogr 1982; 6:437-444.[Medline]
2. Naidich DP, Zerhouni EA, Hutchins GM, Genieser NB, McCauley DI, Siegelman SS. Computed tomography of the pulmonary parenchyma. I. Distal air-space disease. J Thorac Imaging 1985; 1:39-53.
3. Zerhouni EA, Naidich DP, Stitik FP, Khouri NF, Siegelman SS. Computed tomography of the pulmonary parenchyma. II. Interstitial disease. J Thorac Imaging 1985; 1:54-64.[Medline]
4. Grenier P, Maurice F, Musset D, Menu Y, Nahum H. Bronchiectasis: assessment by thin-section CT. Radiology 1986; 161:95-99.[Abstract/Free Full Text]
5. Murata K, Khan A, Herman PG. Pulmonary parenchymal disease: evaluation with high-resolution CT. Radiology 1989; 170:629-635.[Abstract/Free Full Text]
6. Webb WR, Müller NL, Naidich DP. High-resolution CT of the lung 2nd ed. Philadelphia, Pa: Lippincott-Raven, 1996.
7. Mayo JR. High resolution computed tomography: technical aspects. Radiol Clin North Am 1991; 29:1043-1049.[Medline]
8. Engeler CE, Tashjian JH, Engeler CM, Geise RA, Holm JC, Ritenour ER. Volumetric high-resolution CT in the diagnosis of interstitial lung disease and bronchiectasis: diagnostic accuracy and radiation dose. AJR 1994; 163:31-35.[Abstract/Free Full Text]
9. McGuiness G, Naidich DP. Bronchiectasis: CT/clinical correlations. Semin Ultrasound CT MR 1995; 16:395-419.[Medline]
10. Kuhns LR, Borlaza G. The "twinkling star" sign: an aid in differentiating pulmonary vessels from pulmonary nodules on computed tomograms. Radiology 1980; 135:763-764.[Abstract/Free Full Text]
11. Tarver RD, Conces DJ, Godwin JD. Motion artifacts on CT simulate bronchiectasis. AJR 1988; 151:1117-1119.[Free Full Text]
12. Mayo JR, Webb WR, Gould R, et al. High-resolution CT of the lungs: an optimal approach. Radiology 1987; 163:507-510.[Abstract/Free Full Text]
13. Mayo JR, Müller NL, Henkelman RM. The double-fissure sign: a motion artifact on thin-section CT scans. Radiology 1987; 165:580-581.[Abstract/Free Full Text]
14. Ritchie CJ, Godwin JD, Crawford CR, Stanford W, Anno H, Kim Y. Minimum scan speeds for suppression of motion artifacts in CT. Radiology 1992; 185:37-42.[Abstract/Free Full Text]
15. Lynch DA, Brasch RC, Hardy KA, Webb WR. Pediatric pulmonary disease: assessment with high-resolution ultrafast CT. Radiology 1990; 176:243-248.[Abstract/Free Full Text]
16. Stanford W, Rumberger JA, eds. Ultrafast computed tomography in cardiac imaging: principles and practice Mount Kisco, NY: Futura, 1992.
17. Hayball MP, Coulden RA, Regn J, Fluhrer M, Clements L, Brown SJ. ECG triggered image acquisition on a sub-second CT system (abstr). Radiology 1998; 206:575.
18. Webb WR. High resolution CT of the lung parenchyma. Radiol Clin North Am 1989; 27:1085-1097.[Medline]
19. Zerhouni E. Computed tomography of the pulmonary parenchyma: an overview. Chest 1989; 95:901-907.[Free Full Text]

This article has been cited by other articles:

				R. Eibel, P. Herzog, O. Dietrich, C. T. Rieger, H. Ostermann, M. F. Reiser, and S. O. Schoenberg Pulmonary Abnormalities in Immunocompromised Patients: Comparative Detection with Parallel Acquisition MR Imaging and Thin-Section Helical CT Radiology, December 1, 2006; 241(3): 880 - 891. [Abstract] [Full Text] [PDF]

				V. D. Raptopoulos, P. B. Boiselle, N. Michailidis, J. Handwerker, A. Sabir, J. A. Edlow, I. Pedrosa, and J. B. Kruskal MDCT Angiography of Acute Chest Pain: Evaluation of ECG-Gated and Nongated Techniques Am. J. Roentgenol., June 1, 2006; 186(6_Supplement_2): S346 - S356. [Abstract] [Full Text] [PDF]

				L. K. Hofmann, K. H. Zou, P. Costello, and U. J. Schoepf Electrocardiographically Gated 16-Section CT of the Thorax: Cardiac Motion Suppression Radiology, December 1, 2004; 233(3): 927 - 933. [Abstract] [Full Text] [PDF]

				U. J. Schoepf, C. R. Becker, B. M. Ohnesorge, and E. K. Yucel CT of Coronary Artery Disease Radiology, July 1, 2004; 232(1): 18 - 37. [Abstract] [Full Text] [PDF]

				M. Nishino, M. Kuroki, P. M. Boiselle, J. F. Copeland, V. Raptopoulos, and H. Hatabu Coronal Reformations of Volumetric Expiratory High-Resolution CT of the Lung Am. J. Roentgenol., April 1, 2004; 182(4): 979 - 982. [Abstract] [Full Text] [PDF]

				D. M. Kelly, I. Hasegawa, R. Borders, H. Hatabu, and P. M. Boiselle High-Resolution CT Using MDCT: Comparison of Degree of Motion Artifact Between Volumetric and Axial Methods Am. J. Roentgenol., March 1, 2004; 182(3): 757 - 759. [Abstract] [Full Text] [PDF]

				U. J. Schoepf and P. Costello CT Angiography for Diagnosis of Pulmonary Embolism: State of the Art Radiology, February 1, 2004; 230(2): 329 - 337. [Abstract] [Full Text] [PDF]

				T. Boehm, J. K. Willmann, P. R. Hilfiker, D. Weishaupt, B. Seifert, D. W. Crook, B. Marincek, and S. Wildermuth Thin-Section CT of the Lung: Does Electrocardiographic Triggering Influence Diagnosis? Radiology, November 1, 2003; 229(2): 483 - 491. [Abstract] [Full Text] [PDF]

				U J Schoepf, C R Becker, R D Bruening, B M Ohnesorge, A Huber, L-G Haw, H Hildebrandt, and M F Reiser Multislice CT angiography Imaging, December 15, 2001; 13(5): 357 - 365. [Abstract] [Full Text] [PDF]

				B. Ohnesorge, T. Flohr, C. Becker, A. F. Kopp, U. J. Schoepf, U. Baum, A. Knez, K. Klingenbeck-Regn, and M. F. Reiser Cardiac Imaging by Means of Electrocardiographically Gated Multisection Spiral CT: Initial Experience Radiology, November 1, 2000; 217(2): 564 - 571. [Abstract] [Full Text]

This Article Abstract Figures Only Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Schoepf, U. J. Articles by Reiser, M. F. Search for Related Content PubMed PubMed Citation Articles by Schoepf, U. J. Articles by Reiser, M. F.