Emergency (****); * (*): *-* This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2015 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com 127 Emergency (2015); 3 (4): 127-136 REVIEW ARTICLE Diagnostic Accuracy of Ultrasonography and Radiography in Detection of Pulmonary Contusion; a Systematic Review and Meta-Analysis Mostafa Hosseini1, 2, Parisa Ghelichkhani3, Masoud Baikpour4, Abbas Tafakhori5, 6, Hadi Asady7, Mohammad Javad Haji Ghanbari8, Mahmoud Yousefifard9*, Saeed Safari10 1. Sina Trauma and Surgery Research Center, Tehran University Medical Sciences, Tehran, Iran. 2. Department of Epidemiology and Biostatistics, school of Public Health, Tehran University of Medical Sciences, Tehran, Iran. 3. Department of Intensive Care Nursing, School of Nursing and Midwifery, Tehran University of Medical Sciences, Tehran, Iran. 4. Department of Medicine, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. 5. Department of Neurology, School of Medicine, Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Iran. 6. Iranian Center of Neurological Research, Tehran University of Medical Sciences, Tehran, Iran. 7. Department of Occupational Health Engineering, Faculty of Public Health, Tehran University of Medical Sciences, Tehran, Iran. 8. Emergency Medicine Department, Rasoul Akram Hospital, Iran University of Medical Sciences, Tehran, Iran. 9. Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. 10. Department of Emergency Medicine, Shohadaye Tajrish Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. *Corresponding Author: Mahmoud Yousefifard, Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Poursina Ave, Tehran, Iran. Email: usefifard@razi.tums.ac.ir; Phone/Fax: +982122721155. Received: June 2015; Accepted: August 2015 Abstract Introduction: Ultrasonography is currently being used as one of the diagnostic modalities in various medical emer- gencies for screening of trauma patients. The diagnostic value of this modality in detection of traumatic chest inju- ries has been evaluated by several studies but its diagnostic accuracy in diagnosis of pulmonary contusion is a matter of discussion. Therefore, the present study aimed to determine the diagnostic accuracy of ultrasonography and radiography in detection of pulmonary contusion through a systematic review and meta-analysis. Methods: An extended systematic search was performed by two reviewers in databases of Medline, EMBASE, ISI Web of Knowledge, Scopus, Cochrane Library, and ProQuest. They extracted the data and assessed the quality of the stud- ies. After summarization of data into true positive, false positive, true negative, and false negative meta-analysis was carried out via a mixed-effects binary regression model. Further subgroup analysis was performed due to a significant heterogeneity between the studies. Results: 12 studies were included in this meta-analysis (1681 chest trauma patients, 76% male). Pooled sensitivity of ultrasonography in detection of pulmonary contusion was 0.92 (95% CI: 0.81-0.96; I2= 95.81, p<0.001) and its pooled specificity was calculated to be 0.89 (95% CI: 0.85-0.93; I2 = 67.29, p<0.001) while these figures for chest radiography were 0.44 (95% CI: 0.32-0.58; I2= 87.52, p<0.001) and 0.98 (95% CI: 0.88-1.0; I2= 95.22, p<0.001), respectively. Subgroup analysis showed that the sources of heteroge- neity between the studies were sampling method, operator, frequency of the transducer, and sample size. Conclu- sion: Ultrasonography was found to be a better screening tool in detection of pulmonary contusion. Moreover, an ultrasonography performed by a radiologist / intensivist with 1-5MHz probe has a higher diagnostic value in iden- tifying pulmonary contusions. Key words: Pulmonary contusion; ultrasonography; radiography; diagnostic tests, routine Cite this article as: Hosseini M, Ghelichkhani P, Baikpour M, et al. Diagnostic accuracy of ultrasonography and radiography in detection of pulmonary contusion; a systematic review and meta-analysis. Emergency. 2015;3(4):127-34. Introduction: ulmonary contusion is a common complication of traumatic thoracic injuries. Reports indicate that 25 to 80% of thoracic traumas are associated with pulmonary contusion (1, 2). Various techniques have been proposed for detection of this lesion including clin- ical assessment, chest radiography (CXR), arterial blood gas, and computed tomography (CT) scan (3, 4). CXR is the most common diagnostic tool in detection of pulmo- nary contusion but presence of hemothorax or pneumo- thorax might complicate the diagnosis (5-7). Moreover, identification of this lesion in CXR is not possible in the first 6 hours after injury (8, 9). CT scan is the most accu- rate diagnostic tool for pulmonary contusion and can de- tect the lesion right after the injury (10, 11). Ultrasonography reported to have acceptable sensitivity P This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2015 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com Hosseini et al 128 and specificity in detection of pulmonary contusion (11- 13). In the last 10 years many studies have evaluated the diagnostic values of ultrasonography and radiography in detection of traumatic thoracic injuries including pulmo- nary contusion (14-16), but reaching a consensus has been hindered by the vast disagreements on this subject. One of the ways to overcome this problem is conducting a systematic review and meta-analysis (17, 18). In this regard, we aimed to compare the diagnostic values of these two modalities in detection of pulmonary contu- sion through a meta-analysis of the available literature. Methods: Search strategy and selection criteria Search strategy was based on the keywords related to ul- trasonography and chest radiography including “Ultra- sonography” OR “Sonography” OR “Ultrasound” OR “Chest Film” OR “Chest Radiograph” combined with pul- monary contusion-related terms including “Contusions” OR “Pulmonary Contusion” OR “Lung Contusion”. The systematic search was carried out in databases of Med- line (via PubMed), EMBASE, ISI Web of Knowledge, Sco- pus, Cochrane Library, and ProQuest directed at finding retrospective and prospective original articles. We run a hand search using Google Scholar for extracting further studies. Bibliographies of the related and review articles were scanned in order to find relevant undiscovered studies in our systematic search. The search keywords were extracted from Medical Subject Heading (MeSH) terms and EMTREE. Review and editorial articles, case reports, letters to ed- itors, poster presentations, and meeting abstracts were excluded from this survey. Application of a reference test other than CT scan and conducting the study on animal samples were also considered as exclusion criteria. Two reviewers (M.Y, P.G) extracted data in true positive (TP), true negative (TN), false positive (FP), and false negative (FN). In cases where these values could not be obtained neither from the article nor by contacting the authors, the survey were excluded from the study. Figure 1: Flowchart of the study. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2015 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com 129 Emergency (2015); 3 (4): 127-136 T a b le 1 : C h a re ct e ri st ic s o f in cl u d e d s tu d ie s S tu d y N o . o f P a ti e n t (+ / - )1 A g e 2 (y e a r s ) M a le (% ) R e fe r e n c e / I n d e x T r a n s d u c e r / O p e r a to r S a m p li n g W e a k n e s s e s L ic h te n s te in 2 0 0 4 ( 1 9 ) 1 8 4 / 2 0 0 5 8 ± 1 5 N R C T / U S , C X R 5 M H z / In te n si v is t C o n se cu ti v e -- -- S o ld a ti 2 0 0 6 ( 1 1 ) 3 7 / 5 1 3 5 ( 1 8 -8 9 ) 7 2 .4 C T / U S , C X R 3 .5 - to 5 -M H z / E P C o n se cu ti v e T h e m o st p a ti e n ts w e re a s- se ss e d r e tr o sp e ct iv e ly E lm a li 2 0 0 7 ( 2 0 ) 3 9 / 2 1 4 3 ( 1 6 -8 5 ) 8 0 C T / C X R N A / R a d io lo g is t C o n se cu ti v e L o w s a m p le s iz e T r a u b 2 0 0 7 ( 2 1 ) 4 4 / 9 7 4 7 ( 1 8 -8 9 ) 7 5 C T / C X R N A / R a d io lo g is t C o n v e n ie n c e R e tr o sp e ct iv e d e si g n P o ss ib il it y o f se le ct io n b ia s R o c c o 2 0 0 8 ( 2 2 ) 6 3 / 1 1 7 4 2 ± 1 4 6 6 .7 C T / U S , C X R 3 .5 M H z / In te n si v is t C o n se cu ti v e L o w s a m p le s iz e X ir o u c h a k i 2 0 1 1 ( 1 3 ) 5 4 / 3 0 5 7 ± 2 1 .5 8 1 C T / U S , C X R 5 – to 9 -M H z / In te n si v is t C o n v e n ie n c e L o w s a m p le s iz e H y a c in th e 2 0 1 2 ( 2 3 ) 1 4 7 / 9 0 3 9 ( 2 2 -5 1 ) 8 2 C T / U S , C X R 5 -t o 2 -M H z / E P C o n se cu ti v e P o ss ib il it y o f se le ct io n b ia s B ła s iń s k a 2 0 1 3 ( 2 4 ) 1 1 / 4 9 N R N R C T / C X R N A / R a d io lo g is t C o n se cu ti v e L o w s a m p le s iz e C h a r d o li 2 0 1 3 ( 2 5 ) 1 1 / 1 8 9 3 8 ( 1 6 -9 0 ) 8 4 C T / C X R N A / E P C o n v e n ie n c e L a ck o f B li n d in g P o ss ib le s e le ct io n b ia s L e b la n c 2 0 1 4 ( 2 6 ) 3 8 / 7 3 6 ( 1 5 -5 6 ) 7 1 C T / U S , C X R 5 -t o 1 -M H z / In te n si v is t C o n v e n ie n c e L o w s a m p le s iz e P o ss ib il it y o f se le ct io n b ia s H e lm y 2 0 1 5 ( 2 7 ) 4 0 / 1 0 3 9 ( 1 8 -6 7 ) 7 0 C T / U S , C X R 5 M H z / R a d io lo g is t C o n v e n ie n c e L o w s a m p le s iz e P o ss ib il it y o f se le ct io n b ia s V a fa e i 2 0 1 5 ( 1 2 ) 4 8 / 1 0 4 3 1 ( 4 -6 7 ) 7 7 .6 C T / U S , C X R 3 .5 -t o 7 -M H z / E P C o n v e n ie n c e P o ss ib il it y o f se le ct io n b ia s 1 , ( + / - ): ( n u m b e r o f p a ti e n t w it h c o n tu si o n / n u m b e r o f p a ti e n t w it h o u t co n tu si o n ); 2 , N u m b e r a re p re se n te d a s m e a n ± s ta n d a rd d e v ia ti o n o r (r a n g e ). C T : C o m p u te d t o m o g ra p h y ; C X R : C h e st r a d io g ra p h y ; E P : E m e rg e n cy p h y si ci a n ; N A : N o t a p p li ca b le ; N R : N o t R e p o rt e d ; U S : U lt ra so n o g ra - p h y . This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2015 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com Hosseini et al 130 Data extraction Two reviewers (M.Y, P.G) independently assessed the ti- tles and abstracts of the articles found in the systematic search. Then the full texts of the potentially relevant ar- ticles were evaluated and the data from the studies that met the inclusion criteria were precisely summarized in details. No time or language limitations were estab- lished. Quality assessment of the articles was performed according to the guidelines suggested by 14-Item Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool (28). Based on this criteria, all included studies were screened for presence of selection, performance, record- ing, and reporting biases. Demographic characteristics of the patients including age, gender, the number of patients with/without pul- monary contusion according to the results of CT scans, characteristics of ultrasound device (transducer, fre- quency) and its operator, blinding status, and sampling method (consecutive, convenience). Finally, the number of TP, TN, TN, and FN cases were recorded. Disagree- ments were solved by the third author (M.H). The method proposed by Sistrom and Mergo (29) was used to extract the data presented as charts. Web-based pro- grams were utilized to calculate the number of TP, TN, TN, and FN cases from the articles in which only the sen- sitivity and specificity were presented. Statistical analysis Analysis was done by STATA 11.0 statistical software via “MIDAS” module. Summary receiver operative curves (SROC), sensitivity, specificity, positive likelihood ratio and negative likelihood ratio of ultrasonography and ra- diography in detection of pulmonary contusion with 95% confidence interval (95% CI) were estimated. In cases where data were presented separately for each hemi-thorax the information were included separately as presented in the original article. Due to the significant heterogeneity between the included studies, mixed ef- fects binary regression model was applied. Heterogene- ity was evaluated through calculation of I2 and χ2 tests and a p value of less than 0.1 along with an I2 greater than 50% were considered as presence of considerable heter- ogeneity (30). In order to recognize the sources of heterogeneity, sub- group analysis was performed considering the sampling method (consecutive/ convenience), operator (emer- gency physician/ other specialists) or the interpreting physician, the ultrasound device’s frequency of the transducer (1-5 MHz/ 5-10 MHz), and sample size (less than 100 patients/ more than 100 patients). In all the analyses, p value of less than 0.05 was considered as sta- tistically significant. Results: Study characteristics Search in the mentioned databases yielded 15 studies that met the inclusion criteria. Further manual search re- sulted in finding 3 more related surveys. After summari- zation and quality assessment, 12 studies were included (11-13, 19-27) (Figure 1). A total of 716 patients with pulmonary contusion and 965 subjects without were evaluated. Their age ranged from 4 to 90 years old and male patients comprised 76% of the study population. The summary of included surveys is presented in Table 1. Diagnostic accuracy of ultrasonography and radiog- raphy in detection of pulmonary contusion were as- sessed simultaneously in eight studies (11-13, 19, 22, 23, 26, 27) and the accuracy of radiography was evaluated individually in four surveys (20, 21, 24, 25). Considera- ble heterogeneity was observed between the studies (P<0.001). No publication bias was observed in evalua- tion of the diagnostic accuracy of ultrasonography (p = 0.97) and chest radiography (p = 0.15) (Figure 2). Meta-analysis - Ultrasonography Area under the curve of SROC for ultrasonography in pulmonary contusion diagnosis was found to be 0.93 (95% CI: 0.91 - 0.95) (Figure 3-A). Pooled sensitivity of ultrasonography in this regard was 0.92 (95% CI: 0.81 - 0.96; I2 = 95.81, p < 0.001) and its pooled specificity was estimated to be 0.89 (95% CI: 0.85 - 0.93; I2 = 67.29, p < 0.001). Ultrasonography had pooled positive and nega- tive likelihood ratios of 8.94 (95% CI: 5.95 - 93.36; I2 = 67.92, p < 0.001) and 0.09 (95% CI: 0.04 - 0.22; I2 = 06.36, p < 0.001), respectively (Figure 4). Table 2 demonstrates the results of subgroup analysis. The sensitivity of this modality was lower when consec- utive sampling method was used (0.87 vs. 0.97), proce- dure was performed via an emergency specialist (0.77 vs. 0.95), sample sizes of higher than 100 patients, the sensitivity (0.86 vs. 0.96), and frequencies of ultrasonog- raphy probe was higher than 5 MHz (0.86 vs. 0.93). - Chest Radiography Data from 12 surveys were included in this part of meta- analysis (11-13, 19-27). Area under the SROC for radiog- raphy in detection of pulmonary contusion was 0.72 (95% CI: 0.67 - 0.75) (Figure 3-B). Pooled sensitivity and specificity of this diagnostic tool were 0.44 (95% CI: 0.32 - 0.58; I2= 87.52, p < 0.001) and 0.98 (95% CI: 0.88 - 1.0; I2 = 95.22, p < 0.001), respectively. Pooled positive and negative likelihood ratios were also calculated to be 19.69 (95% CI: 3.59 - 108.07; I2 = 88.75, p < 0.001) and 0.57 (95% CI: 0.45 - 0.72; I2 = 93.13, p < 0.001), respec- tively (Figure 5). Subgroup analysis showed that the sensitivity of radiog- raphy is affected by the interpreting physician of the plain film (emergency physician/ other specialists) and sample size (Table 2). According to the results of this analysis, the sensitivity of this imaging modality is higher when the radiographs were interpreted by a radiologist or intensivist (0.49; 95% CI: 0.30-0.68) compared to an This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2015 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com 131 Emergency (2015); 3 (4): 127-136 T a b le 2 : S u b g ro u p a n a ly si s o f d ia g n o st ic a cc u ra cy f o r ch e st r a d io g ra p h y a n d u lt ra so n o g ra p h y i n d e te ct io n o f p u lm o n a ry c o n tu si o n C o v a r ia te N o . o f s tu d ie s B iv a r ia te r a n d o m -e ff e c t m o d e l S e n s it iv it y ( 9 5 % C I) P S p e c if ic it y ( 9 5 % C I) p h e te r o g e n e it y , I 2 P * U lt r a s o n o g r a p h y P a ti e n t e n r o ll m e n t C o n se cu ti v e 5 0 .8 7 ( 0 .7 8 -0 .9 6 ) 0 .1 6 0 .9 0 ( 0 .8 6 -0 .9 5 ) < 0 .0 0 1 4 9 .0 % 0 .1 4 C o n v e n ie n c e 3 0 .9 7 ( 0 .9 4 -1 .0 0 ) 0 .8 8 ( 0 .8 2 -0 .9 5 ) O p e r a to r E m e rg e n cy p h y si ci a n 3 0 .7 7 ( 0 .6 2 -0 .9 3 ) < 0 .0 0 1 0 .9 0 ( 0 .8 4 -0 .9 5 ) < 0 .0 0 1 6 8 .0 % 0 .0 4 O th e r p h y si ci a n 5 0 .9 5 ( 0 .9 2 -0 .9 9 ) 0 .8 9 ( 0 .8 4 -0 .9 4 ) S a m p le s iz e < 1 0 0 4 0 .9 6 ( 0 .9 0 -1 .0 0 ) 0 .3 8 0 .9 4 ( 0 .8 9 -0 .9 9 ) < 0 .0 0 1 5 5 .0 % 0 .1 1 ≥ 1 0 0 4 0 .8 6 ( 0 .7 3 -0 .9 9 ) 0 .8 8 ( 0 .8 4 -0 .9 5 ) F r e q u e n c y 1 -5 M H z 5 0 .9 3 ( 0 .8 7 -1 .0 ) 0 .4 1 0 .8 8 ( 0 .8 4 -0 .9 1 ) < 0 .0 0 1 5 8 .0 % 0 .0 9 5 -1 0 M H z 3 0 .8 6 ( 0 .6 5 -1 .0 ) 0 .9 3 ( 0 .8 9 -0 .9 8 ) R a d io g r a p h y P a ti e n t e n r o ll m e n t C o n se cu ti v e 6 0 .4 5 ( 0 .2 6 -0 .6 3 ) 0 .9 0 0 .9 9 ( 0 .9 6 -1 .0 0 ) 0 .7 2 0 .0 % 0 .6 1 C o n v e n ie n c e 6 0 .4 4 ( 0 .2 4 -0 .6 3 ) 0 .9 5 ( 0 .8 5 -1 .0 0 ) O p e r a to r E m e rg e n cy p h y si ci a n 6 0 .4 0 ( 0 .2 1 -0 .5 8 ) 0 .7 4 0 .9 8 ( 0 .9 4 -1 .0 0 ) 0 .0 3 0 .0 % 0 .7 9 O th e r p h y si ci a n 6 0 .4 9 ( 0 .3 0 -0 .6 8 ) 0 .9 7 ( 0 .9 0 -1 .0 0 ) S a m p le s iz e < 1 0 0 6 0 .5 5 ( 0 .3 8 -0 .7 2 ) 0 .1 5 0 .9 4 ( 0 .8 2 -1 .0 0 ) 0 .9 9 3 6 .0 % 0 .2 1 ≥ 1 0 0 6 0 .3 5 ( 0 .1 9 -0 .5 1 ) 0 .9 9 ( 0 .9 7 -1 .0 0 ) *, P v a lu e < 0 .1 w a s co n si d e re d a s si g n if ic a n t fo r h e te ro g e n e it y ; C I: C o n fi d e n c e i n te rv a l. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2015 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com Hosseini et al 132 emergency specialist (0.40; 95% CI: 0.21 - 0.58). Discussion: The present meta-analysis is the first to assess the diag- nostic accuracy of ultrasonography and radiography in detection of pulmonary contusion. The results illustrate a higher sensitivity of ultrasonography compared to ra- diography (0.92 vs. 0.44) in this regard, whereas the specificity of radiography was slightly higher (0.97 vs. 0.89). Since these two imaging modalities are the first di- agnostic tools for assessment of traumatic thoracic inju- ries, their screening accuracy is of utmost importance. Accordingly, ultrasonography has better screening per- formance characteristics in detection of pulmonary con- tusion compared to radiography. Various studies have pointed out the fact that diagnostic accuracy of ultrasonography is directly dependent on the skills of the operator (14, 15, 31, 32). Findings of the present survey were also congruent with this statement to some extent. The results demonstrated a higher sen- sitivity of ultrasonography in detection of pulmonary contusion when performed by a radiologist or an inten- sivist compared to emergency specialists. This might be due to the nature of pulmonary contusion whose diag- nostic signs are very challenging to detect. The most im- portant signs of pulmonary contusion identified by ultra- sonography include multiple B-lines and an irregularly delineated tissue image which might be a moderately hypo-echoic blurred lesion (16). Furthermore, after ob- servation of these signs, the operator should rule out pneumothorax as well. Therefore, experience plays an important role in pulmonary contusion diagnosis. Frequency of transducer was another factor affecting the diagnostic accuracy of ultrasonography. Application of transducers with frequencies lower than 5MHz yield greater diagnostic values compared to higher. This find- ing is also related to the nature of the lesion. Contusion in characterized by parenchymal injuries and accumula- tion of fluid and blood in the lung tissues (16). These tis- sues lie in the deepest layers of chest cavity and so the penetrating power of ultrasound wave is more im- portant than the image resolution (which is directly re- lated to the wave’s frequency). Since ultrasound waves with lower frequencies have greater penetrating pow- ers, application of these probes increases the chances of pulmonary contusion diagnosis. Sample size was also found to have an effect on diagnostic values of ultraso- nography and radiography in detection of pulmonary contusion. The sensitivity of both these modalities was found to be higher in the studies with sample sizes of less than 100 patients. This might be due to possible selec- tion bias in these studies (33). Selection of patients with severe traumas and so the higher chances of injury iden- tification via imaging would be prominent in these stud- ies. Moreover in some of these surveys, pneumothorax patients had been excluded which might have made the diagnosis easier (27). Utilization of three strategies has improved the quality of the present meta-analysis. Firstly, comprehensive search in databases to include the maximum number of related surveys and secondly, elimination of publication bias. Thirdly, the effects of heterogeneity between the studies were controlled by subgroup analysis. On the other hand, simultaneous inclusion of retrospec- tive and prospective studies might be considered as a limitation of this study. However, evaluation of outliers on the scatterplot based on standardized predictive ran- dom effects revealed that retrospective surveys are not the cause of diversity between the studies. Moreover, due to the observational nature of included studies, pre- cise assessment of causal relationships was impossible. Conclusion: The results of present meta-analysis revealed the better screening performance characteristics of chest ultraso- nography compared to radiography in detection of pul- monary contusion. It should be mentioned that these characteristics where dependent on operator and char- acteristics of device. Acknowledgments: None Conflict of interest: None Funding support: This research has been supported by Tehran University of Medical Sciences & health Services grant number: 93- 02-38-25618. Authors’ contributions: All authors passed four criteria for authorship contribu- tion based on recommendations of the International Committee of Medical Journal Editors. References: 1. 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Accuracy of emergency physician-performed ultrasound in detecting traumatic pneumothorax after a 2-h training course. Eur J Emerg Med. 2013;20(3):173-7. 32. Lee JH, Jeong YK, Park KB, Park JK, Jeong AK, Hwang JC. Operator-dependent techniques for graded compression sonography to detect the appendix and diagnose acute appendicitis. Am J Roentgenol. 2005;184(1):91-7. 33. Deeks JJ, Macaskill P, Irwig L. The performance of tests of publication bias and other sample size effects in systematic reviews of diagnostic test accuracy was assessed. J Clin Epidemiol. 2005;58(9):882-93. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2015 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com Hosseini et al 134 A B Figure 2: Deeks’ funnel plot asymmetry test for assessment of publication bias. P values < 0.05 were considered as significant. Ultraso- nography (A); Radiography (B). ESS: Effective sample sizes. A B Figure 3: Summary receiver operative curves (SROC) with prediction and confidence contours of ultrasonography (A) and chest radi- ography (B) in detection of pulmonary contusion. AUC: Area under the curve; SENS: Sensitivity; SPEC: Specificity. 1 2 3 4 5 6 7 8.05 .1 .15 .2 1 /r o ot (E SS ) 1 10 100 1000 Diagnostic Odds Ratio Study Regression Line Deeks' Funnel Plot Asymmetry Test pvalue = 0.97 1 2 3 4 5 6 7 8 9 10 11 12.05 .1 .15 .2 1 /r o o t( E SS ) 1 10 100 1000 Diagnostic Odds Ratio Study Regression Line Deeks' Funnel Plot Asymmetry Test pvalue = 0.15 1 2 3 4 5 6 7 8 0.0 0.5 1.0 Se n si ti v it y 0.00.51.0 Specificity Observed Data Summary Operating Point SENS = 0.92 [0.81 - 0.96] SPEC = 0.89 [0.85 - 0.93] SROC Curve AUC = 0.93 [0.91 - 0.95] 95% Confidence Contour 95% Prediction Contour SROC with Prediction & Confidence Contours 1 2 3 4 5 6 7 8 9 10 11 12 0.0 0.5 1.0 S en si ti v it y 0.00.51.0 Specificity Observed Data Summary Operating Point SENS = 0.44 [0.32 - 0.58] SPEC = 0.98 [0.88 - 1.00] SROC Curve AUC = 0.72 [0.67 - 0.75] 95% Confidence Contour 95% Prediction Contour SROC with Prediction & Confidence Contours This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2015 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com 135 Emergency (2015); 3 (4): 127-136 A B Figure 4: Forest plot of screening performance characteristics of chest ultrasonography in detection of pulmonary contusion. Sensitivity and specificity (A); Diagnostic likelihood ratio (DLR) (B). CI: Confidence interval. SENSITIVITY (95% CI) Q =167.02, df = 7.00, p = 0.00 I2 = 95.81 [94.03 - 97.59] 0.92[0.81 - 0.96] 0.69 [0.54 - 0.81] 0.98 [0.87 - 1.00] 0.92 [0.79 - 0.98] 0.61 [0.53 - 0.69] 0.94 [0.85 - 0.99] 0.89 [0.78 - 0.95] 0.95 [0.82 - 0.99] 0.98 [0.95 - 1.00]0.98 [0.95 - 1.00] Author / year COMBINED Vafaei 2015 Helmy 2015 Leblanc 2014 Hyacinthe 2012 Xirouchaki 2011 Rocco 2008 Soldati 2006 Lichtenstein 2004 0.5 1.0 SPECIFICITY (95% CI) Q = 21.40, df = 7.00, p = 0.00 I2 = 67.29 [42.90 - 91.69] 0.89[0.85 - 0.93] 0.92 [0.85 - 0.97] 0.90 [0.55 - 1.00] 0.86 [0.42 - 1.00] 0.80 [0.70 - 0.88] 0.93 [0.78 - 0.99] 0.89 [0.82 - 0.94] 0.96 [0.87 - 1.00] 0.88 [0.83 - 0.92]0.88 [0.83 - 0.92] Author / year COMBINED Vafaei 2015 Helmy 2015 Leblanc 2014 Hyacinthe 2012 Xirouchaki 2011 Rocco 2008 Soldati 2006 Lichtenstein 2004 0.4 1.0 DLR POSITIVE (95% CI) Q = 36.16, df = 7.00, p = 0.00 I2 = 67.92 [67.92 - 93.36] 8.64[5.95 - 12.55] 8.94 [4.47 - 17.86] 9.75 [1.52 - 62.63] 6.45 [1.05 - 39.67] 3.06 [1.99 - 4.72] 14.17 [3.71 - 54.13] 8.00 [4.76 - 13.45] 24.12 [6.19 - 94.04] 8.20 [5.63 - 11.94]8.20 [5.63 - 11.94] Author / year COMBINED Vafaei 2015 Helmy 2015 Leblanc 2014 Hyacinthe 2012 Xirouchaki 2011 Rocco 2008 Soldati 2006 Lichtenstein 2004 1.0 94.0 DLR NEGATIVE (95% CI) Q =192.42, df = 7.00, p = 0.00 I2 = 96.36 [94.89 - 97.84] 0.09[0.04 - 0.22] 0.34 [0.22 - 0.52] 0.03 [0.01 - 0.19] 0.09 [0.03 - 0.28] 0.48 [0.39 - 0.61] 0.06 [0.02 - 0.18] 0.13 [0.06 - 0.25] 0.06 [0.01 - 0.22] 0.02 [0.01 - 0.06]0.02 [0.01 - 0.06] Author / year COMBINED Vafaei 2015 Helmy 2015 Leblanc 2014 Hyacinthe 2012 Xirouchaki 2011 Rocco 2008 Soldati 2006 Lichtenstein 2004 0 1 This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2015 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com Hosseini et al 136 A B Figure 5: Forest plot of screening performance characteristics of chest radiography in detection of pulmonary contusion. Sensi- tivity and specificity (A); Diagnostic likelihood ratio (DLR) (B). CI: Confidence interval. SENSITIVITY (95% CI) Q = 87.52, df = 11.00, p = 0.00 I2 = 87.43 [81.52 - 93.34] 0.44[0.32 - 0.58] 0.44 [0.29 - 0.59] 0.40 [0.25 - 0.57] 0.79 [0.63 - 0.90] 0.00 [0.00 - 0.28] 0.73 [0.39 - 0.94] 0.29 [0.22 - 0.37] 0.46 [0.33 - 0.60] 0.24 [0.14 - 0.36] 0.52 [0.37 - 0.68] 0.69 [0.52 - 0.83] 0.27 [0.14 - 0.44] 0.60 [0.52 - 0.67]0.60 [0.52 - 0.67] Author / year COMBINED Vafaei 2015 Helmy 2015 Leblanc 2014 Chardoli 2013 Blasinska 2013 Hyacinthe 2012 Xirouchaki 2011 Rocco 2008 Traub 2007 Elmali 2007 Soldati 2006 Lichtenstein 2004 0.0 0.9 SPECIFICITY (95% CI) Q =230.14, df = 11.00, p = 0.00 I2 = 95.22 [93.53 - 96.91] 0.98[0.88 - 1.00] 0.73 [0.63 - 0.81] 0.90 [0.55 - 1.00] 0.43 [0.10 - 0.82] 1.00 [0.98 - 1.00] 1.00 [0.93 - 1.00] 0.94 [0.88 - 0.98] 0.80 [0.61 - 0.92] 0.97 [0.91 - 0.99] 1.00 [0.96 - 1.00] 0.76 [0.53 - 0.92] 1.00 [0.93 - 1.00] 1.00 [0.98 - 1.00]1.00 [0.98 - 1.00] Author / year COMBINED Vafaei 2015 Helmy 2015 Leblanc 2014 Chardoli 2013 Blasinska 2013 Hyacinthe 2012 Xirouchaki 2011 Rocco 2008 Traub 2007 Elmali 2007 Soldati 2006 Lichtenstein 2004 0.1 1.0 DLR POSITIVE (95% CI) Q =138.09, df = 11.00, p = 0.00 I2 = 88.75 [88.75 - 95.32] 19.69[3.59 - 108.07] 1.62 [1.04 - 2.55] 4.00 [0.60 - 26.68] 1.38 [0.71 - 2.68] 15.83 [0.33 - 763.86] 70.83 [4.39 - 1000] 5.27 [2.17 - 12.80] 2.31 [1.07 - 5.01] 6.96 [2.41 - 20.09] 102.36 [6.36 - 1000] 2.91 [1.32 - 6.43] 28.74 [1.74 - 475.43] 240.11 [15.03 - 1000]240.11 [15.03 - 1000] Author / year COMBINED Vafaei 2015 Helmy 2015 Leblanc 2014 Chardoli 2013 Blasinska 2013 Hyacinthe 2012 Xirouchaki 2011 Rocco 2008 Traub 2007 Elmali 2007 Soldati 2006 Lichtenstein 2004 0.3 1000.0 DLR NEGATIVE (95% CI) Q =160.00, df = 11.00, p = 0.00 I2 = 93.13 [90.41 - 95.84] 0.57[0.45 - 0.72] 0.77 [0.58 - 1.00] 0.67 [0.48 - 0.92] 0.49 [0.17 - 1.00] 0.96 [0.85 - 1.00] 0.29 [0.12 - 0.71] 0.75 [0.67 - 0.84] 0.67 [0.49 - 0.91] 0.79 [0.68 - 0.91] 0.48 [0.35 - 0.65] 0.40 [0.24 - 0.68] 0.73 [0.60 - 0.89] 0.40 [0.34 - 0.48]0.40 [0.34 - 0.48] Author / year COMBINED Vafaei 2015 Helmy 2015 Leblanc 2014 Chardoli 2013 Blasinska 2013 Hyacinthe 2012 Xirouchaki 2011 Rocco 2008 Traub 2007 Elmali 2007 Soldati 2006 Lichtenstein 2004 0 1 Introduction: Methods: Search strategy and selection criteria Data extraction Statistical analysis Results: Study characteristics Meta-analysis Discussion: Conclusion: Acknowledgments: Conflict of interest: Funding support: Authors’ contributions: References: