Archives of Academic Emergency Medicine. 2023; 11(1): e24 REV I EW ART I C L E Diagnostic Accuracy of Ultrasonography for Detection of Intussusception in Children; a Systematic Review and Meta-Analysis Erfan Rahmani1, Reza Amani-Beni2, Yasaman Hekmatnia3, Amirhossein Fakhre Yaseri4, Seyed Amirabbas Ahadiat5, Parham Talebi Boroujeni6, Moein Kiani7, Reza Tavakoli2, Seyyed-Ghavam Shafagh8, Matin Shirazinia9, Setareh Garousi9, Mehran Mottahedi9, Mohammadreza Arzaghi10, Sasan Pourbagher Benam11, Amir Rigi12, Amir Salmani13, Zeynab Abdollahi14, Fateme Karimzade Rokni15, Tara Nikbakht16, Saeme Azizi Hassan Abadi15, Roozbeh Roohinezhad8, Forough Masheghati17, Yas Haririan18, Bahar Darouei2, Ehsan Fayyazishishavan19, Niusha Manoochehri-Arash20, Mehrdad Farrokhi21∗ 1. School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. 2. School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. 3. Islamic Azad University of Medical Science, Sari, Mazandaran, Iran. 4. School of Medicine, Qazvin University of Medical Sciences, Qazvin, lran. 5. The Advocate Center for Clinical Research, Ayatollah Yasrebi Hospital, Kashan, Iran. 6. Advanced Diagnostic Interventional Radiology Research Center, Tehran University of Medical Science, Tehran, Iran. 7. School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran. 8. Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran. 9. Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran. 10.Shahid Beheshti University of Medical Sciences, Tehran, Iran. 11.Faculty of Medicine, Urmia University of Medical Sciences, Urmia, Iran. 12.Islamic Azad University, Zahedan Branch, Zahedan, Iran. 13.Mechanical Engineering, Sharif University of Technology, Tehran, Iran. 14.Department of Radiology, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. 15.Faculty of Medical Sciences, Islamic Azad University of Chalus, Chalus, Mazandaran, Iran. 16.Islamic Azad University, Tehran Medical Branch, Tehran, Iran. 17.School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran. 18.School of Medicine, Shiraz university of Medical Sciences, Shiraz, Iran. 19.Department of Biostatistics and Data Science, School of Public Health, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX 77030, USA. 20.Harvard Medical School, Boston, Massachusetts, USA; Division of Endocrinology, Diabetes, Hypertension Brigham and Women’s Hospital, Boston, Massachusetts, USA. 21.ERIS Research Institute, Tehran, Iran. Received: December 2022; Accepted: January 2023; Published online: 28 February 2023 This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index E. Rahmani et al. 2 Abstract: Introduction: The diagnosis of intussusception can be challenging in children due to the fact that the findings of clinical evaluations are nonspecific and most of the patients present with unclear history. Therefore, in this systematic review and meta-analysis, we aimed to investigate the diagnostic accuracy of ultrasonography for detection of intussusception and also compare the efficacy of point-of-care ultrasound (POCUS) with radiologist-performed ultrasound (RADUS). Methods: Two independent reviewers systematically searched different online electronic databases including MED- LINE, Scopus, Web of Science, Google Scholar, Embase, and Cochrane from inception to December 1, 2022 to identify published papers reporting accuracy of ultrasonography for diagnosis of intussusception. The quality assessment of the included studies was investigated using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 tool. Results: A total of 1446 records were retrieved in the initial search of databases. After screening the titles, a total of 344 studies were retrieved for the detailed assessment of full-text. Finally, 37 studies were included in qualitative and quantitative analysis. The pooled sensitivity and specificity of ultrasonography for diagnosis of intussusception were 0.96 (95% CI: 0.95-0.97) and 0.97 (95% CI: 0.97-0.98), respectively. The pooled positive likelihood ratio (PLR) and nega- tive likelihood ratio (NLR) were 24.57 (95% CI: 8.26-73.03) and 0.05 (95% CI: 0.04-0.08), respectively. The area under the hierarchical summary receiver operating characteristic (HSROC) curve was 0.989. Mete-regression showed that there is no significant difference between diagnostic performance of POCUS and RADUS (p = 0.06 and rDOR (diagnostic odds ratio) = 4.38 (95% CI: 0.92-20.89)). Conclusion: This meta-analysis shows that ultrasonography has excellent sensitiv- ity, specificity, and accuracy for diagnosis of intussusception in pediatric patients. Moreover, we found that diagnostic performance of POCUS is similar to that of RADUS for diagnosis of intussusception. Keywords: Intussusception; Ultrasonography; Point-of-Care Testing; Diagnostic Imaging; Meta-analysis Cite this article as: Rahmani E, Amani-Beni R, Hekmatnia Y, et al. Diagnostic Accuracy of Ultrasonography for Detection of Intussusception in Children; a Systematic Review and Meta-Analysis. Arch Acad Emerg Med. 2023; 11(1): e24. https://doi.org/10.22037/aaem.v11i1.1914. 1. Introduction Intussusception is the most prevalent cause of intestinal ob- struction among the pediatric population younger than 6 years old, occurring in 1.1 to 4.3 children per 1,000 live births in Europe and 0.5 to 2.3 children per 1,000 live births in United States with the male to female ratio between 1.4:1 to 4:1 (1). If this obstructive condition is left undiagnosed and untreated, it can potentially lead to fatal complications such as intestinal gangrene, necrosis, perforation, and death. In- deed, prompt and appropriate diagnosis and management of intussusception in children is crucial to achieve a success- ful reduction using air enema (2). The diagnosis of intussus- ception can be challenging in children due to the fact that the findings of clinical and physical evaluations are nonspe- cific and most of the patients are younger than two years old, presenting with unclear history and symptoms such as abdominal discomfort and crying. Previous studies have shown that the classic triad of colicky abdominal pain, vom- iting, and “currant jelly” stool are found in less than 40% of cases on presentation to emergency departments, which means that more than 60% of cases are indistinguishable from acute gastroenteritis (3). Abdominal ultrasonography is gradually emerging as the standard criterion for diagno- sis in the emergency department due to its advantage of be- ∗Corresponding Author: Mehrdad Farrokhi; ERIS Research Institute, Tehran, Iran. Email: dr.mehrdad.farrokhi@gmail.com, ORCID: https://orcid.org/0000- 0002-1559-2323. ing cost-effective, non-invasive, and radiation-free. Although barium enema is known as the gold standard for diagnosis of intussusception, this modality requires an experienced radi- ologist, is expensive and invasive, and exposes cases to radi- ation, making it impractical in outpatient setting and emer- gency departments. There is a growing body of literature sug- gesting ultrasonography as a rapid, safe, and reliable imaging modality for diagnosis of intussusception in children (4-7). Although multiple diagnostic studies have been recently published and ultrasound is suggested for the diagnosis of in- tussusception, their results were controversial with relatively wide confidence intervals. Moreover, previous investigations have proposed that sonographers with limited experience or pediatric physicians as well as experienced radiologists can perform point-of-care ultrasound (POCUS) (8-10). However, to the best of our knowledge, the comparison of diagnos- tic accuracy of POCUS and radiologist-performed ultrasound (RADUS) for detection of intussusception has not been car- ried out in a systematic review and meta-analysis. Therefore, in this systematic review and meta-analysis, we aimed to in- vestigate the diagnostic accuracy of ultrasonography for de- tection of intussusception and also compare the efficacy of POCUS with RADUS in this regard. 2. Methods 2.1. Literature Search This systematic review and meta-analysis was carried out ac- cording to the guidelines of Preferred Reporting Items for This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index 3 Archives of Academic Emergency Medicine. 2023; 11(1): e24 Systematic Reviews and Meta-analysis of Diagnostic Test Ac- curacy Studies (PRISMA-DTA). Two independent reviewers (MF and RAB) systematically searched different online elec- tronic databases including MEDLINE, Scopus, Web of Sci- ence, Google Scholar, Embase, and Cochrane from incep- tion to December 1, 2022 to identify published papers report- ing accuracy of ultrasonography for diagnosis of intussus- ception. The following keywords and Medical Subject Head- ing (MeSH) Terms and also their combinations with Boolean operators ‘’AND” and ‘’OR” were used for systematic search of the databases: “ultrasonography” OR “ultrasound” OR “sonography” OR “ultrasonic” OR “US” OR “medical sonog- raphy” AND “intestinal invagination” OR “intussusception”. The references of the identified papers were also screened to retrieve the relevant articles more comprehensively. The dis- agreements between two reviewers were resolved via a con- sensus meeting or by a third reviewer. 2.2. Eligibility Criteria The eligible studies were included in our meta-analysis ac- cording to the following inclusion criteria: 1) diagnostic ac- curacy data including true positive (TP), false positive (FP), true negative (TN), and false negative (FN) can be extracted from a 2×2 table directly or data are available to calculate these items; 2) reported the diagnostic performance of ul- trasonography for detection of intussusception; 3) the num- ber of included cases was 10 or more; 4) the definite diag- nosis came from the result of air or barium enema, surgical report, clinical follow-up, and finings of imaging by experi- enced radiologist or combination of them; 5) included cases <18 years old presenting with manifestations suggestive of intussusception. Meta-analysis, reviews, comments, case re- ports, case series with less than ten patients, animal and ca- daveric studies, studies with incomplete data regarding di- agnostic characteristics of ultrasonography for diagnosis of intussusception were excluded. 2.3. Data Extraction The following variables were extracted from the included studies using the finalized data extraction excel sheet: first author, year of publication, country, study design, mean age, number of patients, prevalence of intussusception, TP, FP, TN, and FN. Data extraction was carried out by two inde- pendent researchers and any discrepancies were resolved through a consultation with a third researcher. 2.4. Quality Assessment The quality assessment of the included studies was investi- gated using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 tool which evaluates the risk of bias and applicability of each study. Similarly, the quality assessment was performed by two independent researchers and their disagreements were resolved by a third party. 2.5. Data Analysis Statistical analysis was performed using meta-Disc software version 1.4 (Ramona Cajal Hospital, Madrid, Spain) and Stata statistical software package (Stata Corp., College Station, TX, USA) (version 17.0). The heterogeneity between the included studies was assessed using I2 and Cochran-Q test. If the value of I2 was higher than 50% or P-value of Q-test was less than 0.10, DerSimonian-Laird random effect was used. Alterna- tively, if the value of I2 was less than 50% and P-value of Q- test was higher than 0.10, the data were pooled using Mantel- Haenzsel model. Funnel plot, Egger’s test, and Begg’s test were used to investigate the publication bias. 3. Results 3.1. Search Results A total of 1446 records were retrieved in the initial search of databases. Seventeen studies were identified through man- ual search and citation tracking. After screening the titles, we removed 96 duplicated records and excluded 1023 articles based on the pre-defined criteria and a total of 344 studies were retrieved for the detailed assessment of full-text. Finally, 37 studies were included in qualitative and quantitative anal- ysis. The flow of the relevant studies is summarized in Figure 1. 3.2. Main Characteristics Thirty-seven studies with 6453 patients from 17 countries were included in this meta-analysis. These studies were pub- lished between 1986 and 2021. The mean age of the stud- ied cases ranged from 6 to 72 months. The sensitivity and specificity of the studies ranged from 84.6 to 100 and 0 to 100, respectively. In this meta-analysis, we included 20 ret- rospective and 17 prospective cohort studies. Ultrasonogra- phy by an experienced radiologist, clinical follow-up, surgi- cal report, and air or barium enema were the most common gold standards reported in the included studies. True pos- itive (TP), false positive (FP), true negative (TN), and false negative (FN) were also extracted from the studies. The main characteristics of the included studies are summarized in Ta- ble 1. 3.3. Quality Assessment The quality assessment of the included studies was carried out using QUADAS-2 tool. The detailed results of this assess- ment are shown in table 2. Taken together, the overall results of quality assessment suggest good quality. Some items of QUADAS-2 were not well-described in conference abstracts, which led to high risk of bias. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index E. Rahmani et al. 4 Table 1: Characteristics of the included studies Authors Year Country Study Design Age (months) Number TP TN FP FN Sensitivity Specificity Prevalence Arnaud et al. (19) 1986 France Retrospective - 32 8 23 1 0 100 96 25% Pracros J.P et al. (20) 1990 France Prospective - 426 145 281 0 0 100 100 34% Bhisitkul et al. (21) 1992 USA Prospective 17 65 20 42 3 0 100 93 31% Verschelden et al. (22) 1992 USA Prospective 18 83 34 43 6 0 100 88 41% Woo et al. (23) 1992 South Korea Prospective 10 82 75 7 0 0 100 100 91% Lim et al. (24) 1994 South Korea Prospective <18 y 176 64 112 0 0 100 100 36% Shanbhogue et al. (25) 1994 Netherlands Retrospective - 163 128 33 0 2 98.5 100 80% Barzilai et al. (26) 1994 Israel Retrospective - 14 5 8 1 0 100 89 36% Wright et al. (27) 1996 Australia Retrospective - 50 7 41 2 0 100 95 14% Sarihan et al. (28) 1997 Turkey Prospective 38.8 27 21 4 0 2 91 100 85% Stanely et al. (29) 1997 Ireland Prospective 11.4 25 7 16 2 0 100 89 29% John et al. (30) 1998 USA Retrospective 18 151 48 101 1 1 99 98 32% Harrington et al. (31) 1998 Canada Prospective 29.2 245 87 148 7 3 97 95 37% Smoljanić et al. (32) 2000 Serbia Retrospective 21.4 35 26 9 0 0 100 100 74% Henrikson et al. (33) 2003 USA Prospective <18 y 19 11 7 1 0 100 88 58% Eshed et al. (34) 2004 Israel Retrospective 13.8 151 37 104 7 3 93 94 26% Justice et al. (35) 2007 Vietnam Prospective 9.3 585 466 106 1 12 97.5 99 82% Hryhorczuk et al. (36) 2009 USA Retrospective <10 y 812 97 698 15 2 97.9 97.8 12% Muniz et al. (37) 2010 USA Prospective 12.3 198 28 168 0 2 93.3 100 15% Henderson et al. (38) 2011 USA Retrospective 16 286 60 217 8 1 98.4 96.4 21% Riera et al. (10) 2012 USA Prospective 25 82 11 67 2 2 84.6 97.1 16% Lin et al. (39) 2012 Taiwan Retrospective 72 775 15 760 0 0 100 100 2% Zerzan et al. (40) 2012 USA Prospective - 99 8 88 2 1 88.9 97.8 9% Jones et al. (41) 2012 UK Retrospective 8 197 79 113 5 0 100 100 40% Mwango et al. (42) 2012 Kenya Prospective 17 56 18 38 0 0 100 100 32% Kim et al. (43) 2012 South Korea Retrospective 26 38 13 22 2 1 92.9 91.7 37% Usang et al. (44) 2013 Nigeria Retrospective 6 25 20 1 1 3 87 50 92% Chang et al. (8) 2013 Taiwan Retrospective 21 186 151 0 10 25 86 0 95% Lam et al. (9) 2014 USA Retrospective 31 46 10 34 2 0 100 94.1 22% Lim et al. (45) 2015 USA Retrospective 23 100 37 63 0 0 100 100 37% Trigylidas et al. (13) 2017 USA Retrospective 22 105 75 25 2 3 96 92.6 74% Al-Ani et al. (46) 2017 Iraq Retrospective 13 47 34 8 0 5 87 100 72% Van Houwelingen et al. (47) 2018 Germany Retrospective 29 10 8 1 0 1 89 100 90% Lee et al. (7) 2020 South Korea Retrospective 25.5 575 70 483 22 0 100 95.6 13% Arroyo et al. (4) 2021 USA Prospective 24 100 8 89 1 2 88.9 97.8 8% Bergmann et al. (5) 2021 Multi- national Prospective 21.1 256 55 193 5 3 96.6 98 23% La Tour et al. (6) 2021 Canada Prospective 18 131 39 83 3 6 86.7 96.5 34% TN: true negative; TP: true positive; FN: false negative; FP: false positive. 3.4. Meta-analysis Typical “shoulder arm shape” of SROC and spearman cor- relation coefficient between the log of sensitivity and the log of 1 specificity (0.353 with P = 0.03) showed statisti- cally significant threshold effect. The evaluation of the het- erogeneity of the diagnostic characteristics revealed a sig- nificant heterogeneity for sensitivity (I2=68.7% and P<0.01), specificity (I2=81.7% and P<0.01), positive likelihood ratio (PLR) (I2=98.2% and P<0.01), negative likelihood ratio (NLR) (I2=54.7% and P<0.01), and diagnostic odds ratio (DOR) (I2=61.6% and P<0.01). The pooled sensitivity and specificity of ultrasonography for diagnosis of intussusception were 0.96 (95% CI: 0.95-0.97) This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index 5 Archives of Academic Emergency Medicine. 2023; 11(1): e24 Table 2: Quality assessment of the included studies using QUADAS-2 tool Study Risk of bias Applicability concerns Patient selection Index test Reference standard Flow and timing Patient selection Index test Reference standard Arnaud et al. ? ? Pracros J.P ? ? ? Bhisitkul et al. Verschelden et al. Woo et al. Lim et al. § Shanbhogue et al. Barzilai et al. Wright et al. § Sarihan et al. ? ? ? ? Stanely et al. ? John et al. ? § Harrington et al. Smoljanić et al. ? ? ? Henrikson et al. ? Eshed et al. § Justice et al. Hryhorczuk et al. § Muniz et al. ? ? ? Henderson et al. Riera et al. Lin et al. Zerzan et al. ? ? ? ? Jones et al. ? Mwango et al. § Kim et al. § Usang et al. Chang et al. § § Lam et al. Lim et al. § Trigylidas et al. Al-Ani et al. § Van Houwelingen et al. Lee et al. Arroyo et al. § Bergmann et al. § La Tour et al. § § § : Low Risk; §: High Risk; ?: Unclear Risk. and 0.97 (95% CI: 0.97-0.98), respectively (Figure 2 and Figure 3). The PLR and NLR were 24.57 (95% CI: 8.26-73.03) and 0.05 (95% CI: 0.04-0.08), respectively (Figure 4 and Figure 5). The pooled DOR for ultrasonography was 517.45 (95% CI: 260.47- 1027.97; Figure 6). The area under the hierarchical summary receiver operating characteristic (HSROC) curve was 0.989, suggesting that ultrasonography has an acceptable diagnos- tic performance (Figure 7). Meta-regression showed that there was no significant differ- ence between diagnostic performance of POCUS and RADUS for diagnosis of intussusception (P=0.06 and rDOR=4.38 (95% CI: 0.92-20.89)). 3.5. Publication Bias Evaluation of the studies using Egger’s test (P=0.30) and Begg’s test (P=0.50) showed no significant publication bias. Furthermore, funnel plot of the included studies revealed no significant publication bias (Figure 8). 4. Discussion This systematic review and meta-analysis was carried out to investigate the diagnostic accuracy of ultrasonography for intussusception and also compare the efficacy of POCUS with RADUS for diagnosis of intussusception. Our analysis showed that the sensitivity and specificity of ultrasonography This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index E. Rahmani et al. 6 for diagnosis of intussusception are 0.96 and 0.97, respec- tively. The accuracy of ultrasonography was 0.98 according to HSROC. Furthermore, meta-regression revealed that there was no significant difference between POCUS and RADUS for diagnosis of intussusception. Previous studies have shown that the use of POCUS has a pivotal role in the management of life-threatening diseases by providing prompt diagnosis of the diseases (11, 12). In this regard, if not detected and managed early, intussuscep- tion can cause life threating complications such as intestinal gangrene, necrosis, perforation, and death. To reduce the risk of these complications, early diagnosis of intussuscep- tion in emergency departments would be crucial particularly in medical centers with no access to experienced pediatric radiologist (9, 10, 13). Our findings showed that ultrasonog- raphy and particularly POCUS can improve resource utiliza- tion by reducing time to diagnosis and prioritize the man- agement of patients by providing early definitive treatment. Therefore, our results are in line with increasing popularity of POCUS for screening and diagnosis of pediatric emergencies (9, 10, 13). In a similar study, Li et al. (14) investigated the performance accuracy of POCUS and RADUS for diagnosis of intussuscep- tion. They included 14 studies with 2367 patients in their analysis. Their study showed that the sensitivity and speci- ficity of ultrasonography for diagnosis of intussusception are 0.94 and 0.96, respectively. The reported sensitivity and specificity of ultrasonography in their study were lower than ours (sensitivity: 0.96 and specificity: 0.97). However, similar to the results of our meta-regression, they found that there was no significant difference between RADUS and POCUS for diagnosis of intussusception. The difference between the ac- curacy found in our study and this meta-analysis may in part be clarified by the fact that our study included more studies (37 vs. 14), particularly those published before 2000 and af- ter 2017; therefore, our meta-analysis is more comprehensive and updated. Similarly, in their meta-analysis, they found high heterogeneity among the included studies. One possi- ble explanation for this high heterogeneity may be the fact that included studies had different sample sizes, gold stan- dards for confirmation of the diagnosis, duration of follow- up of the patients, designs of the studies, and device types. Traditionally, clinical evaluation and follow-up, X-ray, con- trast enema, CT-scan, and Magnetic resonance imaging (MRI) are used for the diagnosis of pediatric intussusception. X-ray, computed tomography (CT)-scan, and contrast enema are not the first choice for the diagnosis of pediatric intussus- ception as they expose the patient to ionizing radiation and are expensive. Contrast enema is known as the gold standard for detection and management of intussusception in pedi- atric patients, but it should be performed by an experienced pediatric radiologist (15-17). On the other hand, during the last years, ultrasonography has evolved to achieve more pop- ularity as the first choice for the diagnosis of pediatric intus- susception. Although the use of ultrasonography for pedi- atric patients is accompanied with distinct advantages such as being safe, noninvasive, and inexpensive, providing real- time evaluation of the changes, and lacking ionizing radia- tion, this modality of imaging also has some critical limita- tions. Ultrasonography cannot adequately detect pathologi- cal lead points and discriminate ileo-colic from ileo-ileal in- tussusception, which have a pivotal role in prompt and ap- propriate diagnosis and management of intussusception in children (18). The results of our meta-analysis support the increasing ac- ceptance of ultrasonography for diagnosis of intussuscep- tion, but particular attention must be paid to some stud- ies included in our analysis where ultrasonography showed weak diagnostic properties for identification of intussuscep- tion. In this regard, Chang et al. (8) reported that ultrasonog- raphy for intussusception has sensitivity of 0.86 and speci- ficity of 0, which differed considerably from other included studies. This inconsistency might be explained by the mixed use of sonographers with different levels of experience, lack of appropriate patient selection criteria, and the retrospec- tive design of the study. Ultrasonography is considered an operator-dependent modality of imaging in which lack of training and experience of sonographer can lead to misclas- sification bias and low diagnostic accuracy. Our meta-analysis had some limitations such as heterogene- ity in the design of the included studies, difference in expe- rience level of sonographers, use of different gold standards for definite diagnosis of intussusception, and selection bias of the majority of included studies due to the retrospective design. Since the included studies did not control possible confounders, the diagnostic performance of POCUS cannot be easily generalized to all settings. Furthermore, some stud- ies did not report the experience level of sonographer who as- sessed the suspected patients. Finally, it should be noted that we only included studies assessing suspected pediatric cases and our findings are not generalizable to other age groups. 5. Conclusions This meta-analysis shows that ultrasonography has excellent sensitivity, specificity, and accuracy for diagnosis of intussus- ception in pediatric patients. Moreover, we found that diag- nostic performance of POCUS is similar to that of RADUS for diagnosis of intussusception. However, further prospective studies with larger sample size are still required to establish these findings. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index 7 Archives of Academic Emergency Medicine. 2023; 11(1): e24 6. Declarations 6.1. Acknowledgments The authors thank all those who contributed to this study. 6.2. Conflict of interest None. 6.3. Fundings and supports None. 6.4. Authors’ contribution All authors contributed to study design, data collection, writ- ing the draft of the study, and read and approve of final ver- sion. References 1. Organization WH. Acute intussusception in infants and children: incidence, clinical representation and manage- ment: a global perspective. World Health Organization; 2002. 2. Justice FA, Auldist AW, Bines JE. Intussusception: trends in clinical presentation and management. Journal of gas- troenterology and hepatology. 2006;21(5):842-6. 3. Waseem M, Rosenberg HK. Intussusception. Pediatric emergency care. 2008;24(11):793-800. 4. Arroyo AC, Zerzan J, Vazquez H, Dickman E, Likourezos A, Hossain R, et al. 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Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index 9 Archives of Academic Emergency Medicine. 2023; 11(1): e24 Figure 1: Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) flowchart of the literature search and selection of studies that reported accuracy of ultrasonography for diagnosis of intussusception. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index E. Rahmani et al. 10 Figure 2: Forest plot of the pooled sensitivity of ultrasonography for diagnosis of intussusception. CI: confidence interval. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index 11 Archives of Academic Emergency Medicine. 2023; 11(1): e24 Figure 3: Forest plot of the pooled specificity of ultrasonography for diagnosis of intussusception. CI: confidence interval. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index E. Rahmani et al. 12 Figure 4: Forest plot of the pooled positive likelihood ratio (PLR) of ultrasonography for diagnosis of intussusception. CI: confidence interval. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index 13 Archives of Academic Emergency Medicine. 2023; 11(1): e24 Figure 5: Forest plot of the pooled negative likelihood ratio (NLR) of ultrasonography for diagnosis of intussusception. CI: confidence interval. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index E. Rahmani et al. 14 Figure 6: Forest plot of the pooled diagnostic odds ratio (DOR) of ultrasonography for diagnosis of intussusception. CI: confidence interval. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index 15 Archives of Academic Emergency Medicine. 2023; 11(1): e24 Figure 7: Hierarchical summary receiver-operating characteristic (HSROC) curve indicating accuracy of ultrasonography for diagnosis of in- tussusception. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index E. Rahmani et al. 16 Figure 8: Funnel plot of publication bias on the pooled diagnostic odds ratio (DOR) of ultrasonography. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Downloaded from: https://journals.sbmu.ac.ir/aaem/index.php/AAEM/index Introduction Methods Results Discussion Conclusions Declarations References