| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Thoracic Imaging |
1 From the Department of Radiology, the New York Hospital–Cornell Medical Center, 525 E 68th St, New York, NY 10021. From the 1997 RSNA scientific assembly. Received April 23, 1998; revision requested July 2; revision received August 14; accepted October 7. Address reprint requests to S.D.D.
 |
Abstract |
|---|
 TOP Abstract IntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
|---|
MATERIALS AND METHODS: Contrast material–enhanced spiral CT scans obtained in 92 patients clinically suspected of having acute PE were retrospectively reviewed. The presence or absence of parenchymal abnormalities and pleural effusions was noted. The presence of filling defects consistent with central or peripheral PE was recorded.
RESULTS: Twenty-eight patients had CT evidence of PE. Central emboli were evident in 27 (96%) of these patients; 23 (82%) had concomitant central and peripheral emboli, and four (14%) had only central emboli. One patient had an isolated subsegmental clot. Parenchymal abnormalities were seen in 24 (86%) patients with PE and 56 (88%) patients without PE. Atelectasis, the most common finding, was present in 20 (71%) patients with PE and 41 (64%) patients without PE. The only parenchymal abnormality significantly associated with PE was peripheral wedge-shaped opacity, which was seen in seven (25%) patients with PE and three (5%) patients without PE (odds ratio, 6.78; 95% CI = 1.60, 28.62). Pleural effusions were seen in 16 (57%) patients with PE and 36 (56%) patients without PE. In 25 (39%) patients without PE, there were additional CT findings that might suggest an alternative explanation for the acute clinical presentation.
CONCLUSION: Parenchymal and pleural findings at CT are of limited value for differentiating patients with PE from those without PE.
Index terms: Embolism, pulmonary, 60.72 • Lung, CT, 60.12115 • Pleura, CT, 66.12115 • Pulmonary arteries, CT, 944.12915
|
Introduction |
|---|
|
TOPAbstractIntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
|---|
Previous investigators have assessed the sensitivity and specificity of plain chest radiographic findings, including atelectasis, consolidation, Hampton hump, long line shadow, oligemia, central pulmonary artery prominence, and hemidiaphragm elevation in patients with and patients without angiographic evidence of PE (8,9). Overall, it was concluded that these findings had a limited role in predicting the presence of PE.
Parenchymal abnormalities at CT were initially described in a few series of patients who were either known to have or were suspected of having PE (10–12). In a study of 16 patients clinically suspected of having PE (and verified in two patients with pulmonary angiography), Sinner (10) observed the presence of a peripheral wedge-shaped opacity at CT in seven (44%) patients. Wedge-shaped opacity was also a predominant finding in the study of Chintipalli et al (11) and was seen in seven (39%) of 18 patients, most of whom were undergoing CT for the evaluation of chest radiographic abnormalities and were not clinically suspected of having PE. In a recent study, Coche et al (13) reviewed ancillary findings at contrast material–enhanced spiral CT in 88 patients suspected of having PE; all of these patients underwent ventilation-perfusion scintigraphy, and 21 also underwent conventional angiography. In their series, peripheral wedge-shaped opacity was the most common parenchymal finding in patients with PE and was present in 16 (62%) of 26 patients with PE and 17 (27%) of 62 patients without PE (P < .05).
The aim of our study was to compare the frequencies of parenchymal abnormalities and pleural effusions in patients with and patients without evidence of acute PE, as determined on the basis of findings from contrast-enhanced spiral CT performed for the clinical suspicion of PE.
|
MATERIALS AND METHODS |
|---|
|
TOPAbstractIntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
|---|
CT scans were acquired with a HiSpeed Advantage (GE Medical Systems, Milwaukee, Wis) scanner. Contrast-enhanced spiral CT of the pulmonary arteries was performed from the level of the aortic arch to 2 cm below the inferior pulmonary veins, or approximately a 12-cm distance from the aortic arch. Scans were acquired with the patient supine during suspended inspiration or shallow breathing, depending on the patient's level of dyspnea.
Two different protocols were used during this study. In the initial protocol, scans were acquired in a cephalocaudal direction, with 5-mm collimation at a pitch of 1:1. A total volume of 120 mL of nonionic contrast material (iohexol [Omnipaque 300; Nycomed, Princeton, NJ]) was injected intravenously at a rate of 1 mL/sec with a 45-second delay. In the subsequent protocol, scans were acquired in a caudocephalic direction with 3-mm collimation at a pitch of 1.6:1. A total volume of 140 mL of nonionic contrast material was injected intravenously at a rate of 2 mL/sec with a 28-second delay. In each protocol, the 5- or 3-mm scans were reconstructed at 1-mm intervals with a field of view appropriate for the size of the patient. The remainder of the chest, to include the lung apices and bases, was scanned with either 5- or 7-mm collimation.
Images from all 101 examinations were reviewed in random order by two independent radiologists who were unaware of the official CT reports and not involved in the initial selection of cases. Hard copies of the images were reviewed. The images obtained with lung window settings were evaluated first; the images obtained with mediastinal window settings were evaluated at a different session. Final consensus was achieved in all cases, for images obtained with both lung and mediastinal window settings, by means of arbitration with a third radiologist. Any discrepancies among the readers were resolved by reviewing the official CT report and the 1-mm reconstructed images at the workstation.
An initial training session was conducted by using 10 cases not included in this study. The three reviewers discussed how the data sheets were to be completed. Agreement regarding the definition of terms was also established.
On data sheets for the images obtained with lung window settings, the following were recorded: image quality (graded as very good, adequate, and limited), the presence and size of pleural effusions, and the presence and location of any parenchymal abnormality according to lobe. The size of pleural effusions was assessed visually in a semiquantitative manner. "Small," "medium," and "large" effusions were up to 2–3 cm, between 3 and 5 cm, and greater than 5 cm, respectively, in maximum depth. Parenchymal abnormalities that were tabulated included wedge-shaped opacity, atelectasis, linear opacity, ground-glass attenuation, consolidation, nodule, mass, focal patchy increased attenuation, oligemia, and vascular sign. The findings were defined, according to accepted terminology (10,14–16), as follows: (a) Wedge-shaped opacity is a roughly triangular area of increased attenuation, with a broad base against a peripheral pleural surface and the apex directed toward the hilum. (b) Atelectasis is evidence of diminished volume within lung (categorized as lobar, segmental, subsegmental, or linear). (c) Linear opacity is a thin line of increased attenuation. (d) Ground-glass attenuation is hazy increased attenuation within lung that does not obscure bronchial and vascular markings. (e) Consolidation is an area of increased attenuation that obscures the margins of vessels and airway walls. (f) A nodule is a round opacity no larger than 3 cm in diameter. (g) A mass is a solid lesion, without air bronchograms, larger than 3 cm in diameter. (h) Focal patchy increased attenuation is an irregularly shaped area of increased lung attenuation not adequately described with any of the other terms (consolidation, ground-glass attenuation, nodule, or mass). (i) Oligemia is an area of decreased attenuation due to diminished perfusion and is manifested by a decrease in the caliber and number of vessels; decreased attenuation is not attributable to emphysema or presence of a lung cyst or bulla. (j) Vascular sign is a thickened vessel leading to the apex of a wedge-shaped opacity.
On data sheets for images obtained with the mediastinal window settings, the quality of both the images and the contrast opacification was evaluated. Image quality was graded as very good, adequate, or limited. Contrast enhancement was graded as excellent, good, or inadequate. The presence and location of any intraluminal filling defect(s) was recorded. Central PE was defined as the presence of filling defects within the main to lobar pulmonary arteries. Peripheral PE was defined as the presence of defects within segmental and subsegmental arteries. Acute PE was defined as a partial or complete filling defect centrally within the vessel lumen. Chronic PE was defined as an eccentric filling defect contiguous to the vessel wall or with evidence of recanalization. The final diagnosis of PE was made on the basis of the CT findings.
Differences between the two groups of patients, those with and those without CT evidence of PE, were evaluated with respect to the above parenchymal and pleural findings. Statistical significance was determined by calculating the odds ratio and 95% CI for each CT finding to evaluate the increase in the probability of having PE when that particular CT finding is present.
Interobserver agreement was defined as agreement between the initial two reviewers with regard to the presence or absence of PE in each case. In cases that were positive for PE, no attempt was made to match agreement with respect to the location of filling defects.
|
RESULTS |
|---|
|
TOPAbstractIntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
|---|
Thus, 92 patients (35 men, 57 women) comprised the study population. The mean patient age was 65 years (range, 20–96 years). Twenty-eight of the 92 patients had CT evidence of PE, and 64 had negative examinations. The mean age for patients with and patients without PE was comparable at 65 and 64 years, respectively.
Central PE were identified in 27 (96%) of the 28 patients with PE; there were concomitant central and peripheral emboli in 23 (82%) patients and central emboli alone in four (14%). An isolated subsegmental (peripheral) clot was observed in one patient. Emboli were seen on the right in five patients, on the left in four, and bilaterally in 19. Anatomic evaluation of filling defects revealed a total of 207 emboli in 28 patients, or an average of 7.4 (range, one to 15) emboli per patient; 123 emboli were on the right, 81 were on the left, and three were in the main pulmonary artery. PE were characterized as acute in all 28 patients. Overall, there was interobserver agreement for the presence of PE in 27 (96%) of 28 patients; there was agreement for the absence of PE in 57 (89%) of 64 patients.
As shown in Table 1, at least one parenchymal abnormality was seen in the majority of patients: 24 (86%) of the 28 patients with PE and 56 (88%) of the 64 patients without PE. Atelectasis was the most common finding, and its frequency was similar for patients with and patients without PE: 20 (71%) and 41 (64%), respectively (Figs 1, 2). Linear opacity was the next most frequent abnormality due to some overlap with the category of atelectasis, with the finding of linear atelectasis. Ground-glass attenuation, consolidation, nodule, mass, focal patchy increased attenuation, and oligemia were all less common. A vascular sign was seen in only one patient, who had CT evidence of PE.
|
|
|
|
|
|
|
|
Twenty-five (39%) of the 64 patients without CT evidence of PE had either single or combined additional CT findings that may have contributed to the acute clinical presentation. These included large bilateral pleural effusions in three patients, possible adult respiratory distress syndrome, diffuse pneumonia, or both in four; possible lobar pneumonia in four; pulmonary vascular congestion, pulmonary edema, or both in five; marked cardiomegaly in six; pericardial effusion in three; enlarged central pulmonary arteries in three; and a large unilateral loculated pleural effusion, pulmonary Kaposi sarcoma, lymphangitic dissemination of tumor, and aspirated secretions in one patient each (Fig 5).
|
|
|
DISCUSSION |
|---|
|
TOPAbstractIntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
|---|
The importance of a peripheral wedge-shaped opacity as a finding that is very suggestive of PE has been emphasized in several previous articles describing CT findings in patients who were known to have or were suspected of having PE (10–13). In the study by Coche et al (13), wedge-shaped opacity was significantly more common in patients with PE (67%) than in patients without PE (27%). There was also a significant association for linear bands, which were seen in 46% of patients with PE and 21% of those without PE. In our study, wedge-shaped opacity was the only CT finding significantly associated with PE, but it was relatively uncommon, present in 25% of patients with PE and 5% of those without PE. In the radiographic study by Worsley et al (9), wedge-shaped opacity was also seen in about 25% of patients with PE. These authors, however, observed that the positive predictive value of wedge-shaped opacity was only about 30% and that there was no significant difference in the prevalence of this finding in patients with and patients without PE in the PIOPED series.
CT-pathologic correlation has demonstrated that the finding of wedge-shaped opacity at CT is likely to represent pulmonary infarction, that is, an area of lung filled with red blood cells with or without tissue necrosis. The triangular configuration corresponds to increased attenuation within several affected secondary pulmonary lobules, with a broad base abutting a peripheral pleural surface and often with a truncated apex (17). The reported prevalence of pulmonary infarction after PE has been estimated to be 10%–15% in autopsy series (18). In our study, the higher prevalence of 25% for wedge-shaped opacity at CT may reflect differences in the interval between the embolic event and the CT examination. Owing to subsequent resolution of the parenchymal hemorrhage associated with some opacities, a greater number of acute pulmonary infarcts might be detected on CT scans than in autopsy specimens. Even higher frequencies for peripheral wedge-shaped opacity at CT were noted by Chintipalli et al (11) and Sinner (10) (39% and 44%, respectively). In these two studies, the decision to send patients for CT examination may have been influenced by the presence of chest radiographic abnormalities, including wedge-shaped opacity. The reason for the more marked difference between our frequency of 25% and that of 67% observed by Coche et al (13) is unclear. In both series, there was blinded review of parenchymal findings at CT, without knowledge of the presence or absence of PE. The discrepancy may in part be due to differences in patient selection.
Although a peripheral wedge-shaped opacity at CT may indicate the presence of acute PE, this finding is not specific. Other entities, such as pneumonia, tumor, fibrosis, hemorrhage, or edema should also be considered (16). In our study, three patients had wedge-shaped opacities, and no emboli were evident at CT. When we reviewed the clinical charts for these patients, one opacity could be attributed to suspected pneumonia. In the other two patients, the cause of the opacity was undetermined; the possibility of pulmonary infarction resulting from acute emboli that had resolved by the time CT was performed could not entirely be excluded.
It has been suggested that the presence of a vascular sign, a thickened vessel leading to the apex of a wedge-shaped opacity, increases the likelihood that the latter represents PE with infarction (16). In our study, however, a vascular sign was either infrequent or difficult to recognize and was detected in only one patient with PE. Nevertheless, in accord with earlier studies for the distribution of pulmonary infarcts (10,17), there was an overall lower lobe predominance in our series, seen with nine (75%) of the 12 wedge-shaped opacities; 75% of the opacities were also in the same distribution as the vessel occluded by an embolus.
Other patterns of parenchymal abnormality, such as linear opacity, ground-glass attenuation, consolidation, focal patchy increased attenuation, oligemia, nodule, and mass were examined separately in our study. Linear opacity was the most common of these findings, reflecting the fact that there was overlap with the category of atelectasis. There was no significant difference in the frequency of these abnormalities between the two groups. In the study by Worsley et al (9), oligemia was the only radiographic finding that showed any significant correlation with PE and was present in the right and left hemithoraces in 14% and 8% of patients with PE versus 8% and 4% of patients without PE, respectively (P < .05 for the right hemithorax, difference not significant for the left hemithorax). As in our series, however, this finding was very uncommon.
Pleural effusions are often present in the setting of acute PE and are detected on chest radiographs in up to 51% of cases (19). They are usually small and develop soon after the onset of symptoms, reaching a maximal size within the first 3 days (19). The pathogenesis of pleural effusions in the setting of PE remains unclear, but is almost always associated with pulmonary infarction with or without the presence of lung necrosis. In many cases of PE, there are other concomitant disorders that are the cause for effusion (19).
In our series, pleural effusions were observed in 57% of patients with CT evidence of PE, which is comparable to the findings with chest radiography. This frequency was not significantly different for patients without PE (56%), a finding that is in accord with the radiographic study by Worsley et al (9). Very similar findings were also recently observed by Coche et al (13), with pleural effusions seen at CT in 50% of patients with PE and 58% of those without PE. In our series, most effusions were small, both with and without evidence of PE (64% and 58%, respectively). This finding is also in agreement with findings from prior radiographic studies. In contrast to the study by Bynum and Wilson (19), in which 95% of effusions were unilateral, however, we observed that bilateral effusions were more common in both groups (75% and 72% in patients with and patients without PE, respectively). This greater prevalence of bilateral pleural effusions in our study almost certainly reflects the fact that CT is more sensitive than plain radiography in the detection of small effusions. In both our study and that by Coche et al (13), there was no association between the side of unilateral pleural effusions and PE on the same side.
One major advantage of CT over conventional pulmonary angiography in the evaluation of a patient suspected of having PE is the opportunity for concurrent evaluation of other intrathoracic structures in addition to the pulmonary vessels (3,4,20,21). In our study, additional CT findings were noted in 25 (39%) of the 64 patients without CT evidence of PE. Including the 28 patients with CT evidence of PE, an explanation for the acute clinical presentation could therefore be offered in 58% (53 of 92) of the patients undergoing spiral CT examination to rule out PE.
When constructing an optimal protocol for CT pulmonary angiography, several parameters must be considered. These include adequate spatial resolution, imaging volume, acquisition time, and peak vascular enhancement (7,20). In fact, protocols have varied over time and among investigators. In the initial and even the subsequent protocol for this study, the injection rate for intravenous contrast administration was lower than the rate currently used in our department (3 mL/sec). Initially, 5-mm scans were obtained in a cephalocaudal direction at a pitch of 1:1, whereas in the subsequent protocol, 3-mm scans were acquired in a caudocephalic direction at a pitch of 1.6:1. Although these factors represent a potential limitation, we do not believe that the validity of the observations in our study is significantly affected. As part of the exclusion criteria, cases with inadequate image quality or insufficient contrast opacification were excluded. Furthermore, overall interobserver agreement for the presence or absence of PE was excellent. Any discrepancies in the interpretation were resolved with arbitration by a third radiologist, with review of the official CT report and of the 1-mm reconstructed images at the workstation.
Another potential criticism is that spiral CT was used as the standard of reference for the presence or absence of PE. How can one be certain that small emboli were not missed and that these cases were not erroneously included in the "negative PE" category? The high degree of accuracy of spiral CT, with about 90% sensitivity and specificity for detecting emboli to the level of the segmental pulmonary arteries, is currently accepted (7). The prevalence of small subsegmental emboli is still the subject of debate. In the study by Remy-Jardin et al (5), isolated subsegmental emboli were detected at spiral CT in 5% of cases, a result that they observed was comparable to the figure of 5.6% in the PIOPED study. Conversely, in a study examining the distribution of emboli at pulmonary angiography, Oser et al (22) noted a prevalence of 30% for emboli beyond the segmental level; at spiral CT, Goodman et al (2) and van Rossum et al (3) observed a prevalence of 36% and of 20%, respectively. The higher prevalence of subsegmental emboli in the latter three studies may reflect inherent bias due to selection of a subgroup of patients with unresolved clinical and scintigraphic diagnosis of PE (3).
In our study, isolated subsegmental clot was seen in one of the 28 patients with PE. This prevalence is in accord with published findings and supports the view that our study did not exclude a substantial number of emboli. Furthermore, the burden of emboli detected in our study, an average of 7.4 emboli per patient, is within the range reported in the literature. On average, eight emboli per patient were detected at conventional pulmonary angiography in the Urokinase Pulmonary Embolism Trial and 6.2 emboli per patient were identified at spiral CT in the study by Remy-Jardin et al (23).
A final consideration is that the prevalence of preexistent cardiac or pulmonary disease or other underlying disorders is expected to influence the frequency of various parenchymal and pleural findings at CT. As expected, in view of the fact that CT examinations were performed in a hospital-based setting, the majority of our patients had at least one parenchymal abnormality at CT. Atelectasis represented the most common finding, irrespective of the presence or absence of PE.
In conclusion, parenchymal abnormalities were present in the majority of patients who underwent spiral CT for the clinical suspicion of PE. Wedge-shaped opacity was the only CT finding that was significantly associated with CT evidence of acute PE. This finding, however, was relatively uncommon and was also seen in some patients without evidence of PE. Pleural effusions were detected in more than half of the patients, with comparable frequency among those with and those without CT evidence of PE. Finally, in patients without evidence of PE, CT may be helpful in suggesting an alternative diagnosis.
|
Acknowledgments |
|---|
|
Footnotes |
|---|
Author contributions: Guarantors of integrity of entire study, S.D.D., A.A.S.; study concepts, S.D.D.; study design, S.D.D., A.A.S.; definition of intellectual content, S.D.D., A.A.S.; literature research, A.A.S., S.D.D.; data acquisition, all authors; data analysis, A.A.S., S.D.D.; statistical analysis, S.D.D., A.A.S.; manuscript preparation, A.A.S., S.D.D.; manuscript editing, S.D.D.; manuscript review, all authors.
|
References |
|---|
|
TOPAbstractIntroductionMATERIALS AND METHODSRESULTSDISCUSSIONReferences |
|---|
This article has been cited by other articles:
|
|
 |
|
  H. D. Sostman, M. Miniati, A. Gottschalk, F. Matta, P. D. Stein, and M. Pistolesi Sensitivity and Specificity of Perfusion Scintigraphy Combined with Chest Radiography for Acute Pulmonary Embolism in PIOPED II J. Nucl. Med., November 1, 2008; 49(11): 1741 - 1748. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. D. Sostman, P. D. Stein, A. Gottschalk, F. Matta, R. Hull, and L. Goodman Acute Pulmonary Embolism: Sensitivity and Specificity of Ventilation-Perfusion Scintigraphy in PIOPED II Study Radiology, March 1, 2008; 246(3): 941 - 946. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Remy-Jardin, M. Pistolesi, L. R. Goodman, W. B. Gefter, A. Gottschalk, J. R. Mayo, and H. D. Sostman Management of Suspected Acute Pulmonary Embolism in the Era of CT Angiography: A Statement from the Fleischner Society Radiology, November 1, 2007; 245(2): 315 - 329. [Full Text] [PDF]
|
|
|
|
|
|
M.-P. Revel, R. Triki, G. Chatellier, S. Couchon, N. Haddad, A. Hernigou, C. Danel, and G. Frija Is It Possible to Recognize Pulmonary Infarction on Multisection CT Images? Radiology, September 1, 2007; 244(3): 875 - 882. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Matsuoka, Y. Kurihara, K. Yagihashi, H. Niimi, and Y. Nakajima Quantification of Thin-Section CT Lung Attenuation in Acute Pulmonary Embolism: Correlations with Arterial Blood Gas Levels and CT Angiography. Am. J. Roentgenol., May 1, 2006; 186(5): 1272 - 1279. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Mathis, W. Blank, A. Reissig, P. Lechleitner, J. Reuss, A. Schuler, and S. Beckh Thoracic Ultrasound for Diagnosing Pulmonary Embolism: A Prospective Multicenter Study of 352 Patients Chest, September 1, 2005; 128(3): 1531 - 1538. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Patel and E. A. Kazerooni Helical CT for the Evaluation of Acute Pulmonary Embolism Am. J. Roentgenol., July 1, 2005; 185(1): 135 - 149. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Heinrich, M. Uder, D. Tscholl, A. Grgic, B. Kramann, and H.-J. Schafers CT Scan Findings in Chronic Thromboembolic Pulmonary Hypertension: Predictors of Hemodynamic Improvement After Pulmonary Thromboendarterectomy Chest, May 1, 2005; 127(5): 1606 - 1613. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. P. Kanne and T. A. Lalani Role of Computed Tomography and Magnetic Resonance Imaging for Deep Venous Thrombosis and Pulmonary Embolism Circulation, March 30, 2004; 109(12_suppl_1): I-15 - I-21. [Abstract] [Full Text]
|
|
|
|
 |
|
 British Thoracic Society guidelines for the management of suspected acute pulmonary embolism Thorax, June 1, 2003; 58(6): 470 - 483. [Full Text] [PDF]
|
|
|
|
|
|
S. Patel, E. A. Kazerooni, and P. N. Cascade Pulmonary Embolism: Optimization of Small Pulmonary Artery Visualization at Multi-Detector Row CT Radiology, May 1, 2003; 227(2): 455 - 460. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. S. Ginsberg, J. Oh, A. Welber, and D. M. Panicek Clinical Usefulness of Imaging Performed After CT Angiography That Was Negative for Pulmonary Embolus in a High-Risk Oncologic Population Am. J. Roentgenol., November 1, 2002; 179(5): 1205 - 1208. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Arakawa, Y. Kurihara, K. Sasaka, Y. Nakajima, and W. R. Webb Air Trapping on CT of Patients with Pulmonary Embolism Am. J. Roentgenol., May 1, 2002; 178(5): 1201 - 1207. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Romero Candeira, L. Hernandez Blasco, M. J. Soler, A. Munoz, and I. Aranda Biochemical and Cytologic Characteristics of Pleural Effusions Secondary to Pulmonary Embolism Chest, February 1, 2002; 121(2): 465 - 469. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Pistolesi and M. Miniati Imaging techniques in treatment algorithms of pulmonary embolism Eur. Respir. J., February 1, 2002; 19(35_suppl): 28S - 39s. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Cohen and S. A. Sahn Resolution of Pleural Effusions Chest, May 1, 2001; 119(5): 1547 - 1562. [Full Text] [PDF]
|
|
|
|
 |
|
 E. J. R. van Beek, E. M. J. Brouwers, Bing Song, A. H. H. Bongaerts, and M. Oudkerk Lung Scintigraphy and Helical Computed Tomography for the Diagnosis of Pulmonary Embolism: A Meta-Analysis Clinical and Applied Thrombosis/Hemostasis, April 1, 2001; 7(2): 87 - 92. [Abstract] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| RADIOLOGY | RADIOGRAPHICS | RSNA JOURNALS ONLINE |
