Advertisement
Browse Subject Areas
?

Click through the PLOS taxonomy to find articles in your field.

For more information about PLOS Subject Areas, click here.

  • Loading metrics

Open Access

Peer-reviewed

Research Article

Diagnostic utility of CT for small bowel obstruction: Systematic review and meta-analysis

  • Zhengyan Li,

    Roles Data curation, Formal analysis, Methodology, Software, Writing – original draft

    Affiliation Division of Radiology, West China Hospital of Sichuan University, Chengdu, Sichuan, China

    ⨯
  • Ling Zhang,

    Roles Data curation, Formal analysis, Methodology

    Affiliation Division of Nephrology, West China Hospital of Sichuan University, Chengdu, Sichuan, China

    ⨯
  • Xijiao Liu,

    Roles Methodology, Resources, Software

    Affiliation Division of Radiology, West China Hospital of Sichuan University, Chengdu, Sichuan, China

    ⨯
  • Fang Yuan,

    Roles Data curation, Methodology

    Affiliation Division of Radiology, West China Hospital of Sichuan University, Chengdu, Sichuan, China

    ⨯
  • Bin Song

    Roles Conceptualization, Methodology, Resources, Supervision, Writing – review & editing

    songlab_radiology@163.com

    Affiliation Division of Radiology, West China Hospital of Sichuan University, Chengdu, Sichuan, China

    ⨯

Abstract

Background

To perform a systematic review and meta-analysis evaluating the diagnostic performance of computed tomography (CT) for small bowel obstruction (SBO), including diagnostic accuracy, ischemia, predicting surgical intervention, etiology and transition point.

Methods

PubMed/MEDLINE and related databases were searched for research articles published from their inception through August 2018. Findings were pooled using bivariate random-effects and summary receiver operating characteristic curve models. Meta-regression and subgroup analyses were performed to evaluate whether publication year, patient age, enhanced CT, slice thickness and pathogenesis affected classification accuracy.

Results

In total, 45 studies with a total of 4004 patients were included in the analysis. The pooled sensitivity and specificity of CT for SBO were 91% (95% confidence interval [CI]: 84%, 95%) and 89% (95% CI: 81%, 94%), respectively, and there were no differences in the subgroup analyses of age, publication year, enhanced CT and slice thickness. For ischemia, the pooled sensitivity and specificity was 82% (95% CI: 67%, 91%) and 92% (95% CI: 86%, 95%), respectively. No difference was found between enhanced and unenhanced CT based on subgroup analysis; however, high sensitivity was found in adhesive SBO compared with routine causes (96% vs. 78%, P = 0.03). The pooled sensitivity and specificity for predicting surgical intervention were 87% and 73%, respectively. The accuracy for etiology of adhesions, hernia and tumor was 95%, 70% and 82%, respectively. In addition, the pooled sensitivity and specificity for transition point was 92% and 77%, respectively.

Conclusions

CT has considerable accuracy in diagnosis of SBO, ischemia, predicting surgical intervention, etiology and transition point.

Citation: Li Z, Zhang L, Liu X, Yuan F, Song B (2019) Diagnostic utility of CT for small bowel obstruction: Systematic review and meta-analysis. PLoS ONE 14(12): e0226740. https://doi.org/10.1371/journal.pone.0226740

Editor: Jiani Hu, Wayne State University, UNITED STATES

Received: February 22, 2019; Accepted: December 3, 2019; Published: December 30, 2019

Copyright: © 2019 Li et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All relevant data are within the manuscript and its Supporting Information files.

Funding: The authors received no specific funding for this work.

Competing interests: The authors have declared that no competing interests exist.

Introduction

Small bowel obstruction (SBO) is a common emergency diagnosis based on clinical signs and radiographic findings and is estimated to account for 2% of all patients with abdominal pain and 12–16% of hospital admissions in the United States [1, 2]. Although most SBO patients are treated successfully with nasogastric tube decompression, the mortality of SBO increases to 25% if bowel ischemia is present with delayed surgical management [3]. A challenge in the clinical management is that clinical presentation, physical examination findings, and laboratory tests are insufficient to make an accurate diagnosis of SBO, but the management has changed considerably since then due to advancements in imaging technology, such as computed tomography (CT) [3, 4].

There is a consensus regarding the use of CT in the evaluation of patients with SBO [5], and many studies reported that CT is a helpful tool to diagnose SBO, identify causes and the transition point, and most importantly, detect ischemia, which requires prompt surgical intervention [6–18]. However, CT findings about such points exhibit variable diagnostic performance. For example, the sensitivity of CT for diagnosis of SBO varied from 50% to 100%, and the specificity values varied from 57% to 100% [1, 8, 19–22]. Furthermore, many studies reported that CT had high sensitivity and specificity for ischemia of SBO [7, 8, 12, 23–25], but a prospective study [26] showed a poor sensitivity of 15% for ischemia. In addition, several studies showed CT could predict surgical intervention for patients with SBO [9, 11, 13, 27], but a recent study including 108 cases found no correlation between CT findings and surgical intervention [28].

Given the inconsistency in the existing literature, we performed a quantitative meta-analysis using bivariate random-effects and summary receiver operating characteristic models to evaluate the diagnostic performance of CT for SBO, including diagnostic accuracy, ischemia, predicting surgical intervention, etiology and transition point.

Materials and methods

No financial support was received for this research. We performed this systematic review using the guidelines proposed by the Cochrane Collaboration in the Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy (http://srdta.cochrane.org/handbook-dta-reviews). The protocol was registered on PROSPERO (CRD42015024658) [29].

Study selection criteria

  1. Participants
            This review focused on patients with suspected diagnosis of SBO.
  2. Index tests
        CT was the test under evaluation.
  3. Target conditions
        The target condition of this review was to evaluate the diagnostic performance of CT for SBO, including diagnostic accuracy, ischemia, predicting surgical intervention, etiology and transition point.
  4. Reference standards
        The primary reference standard was surgical findings in patients who received surgical intervention. Alternatively, clinical findings and enteroclysis were the reference standards if the patients did not receive any surgical intervention.

Search methods for identification of studies

1). Study selection.

We used the Cochrane risk of bias tool and the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement methodology [30] to report systematic reviews and perform the meta-analysis (S1 Table). Two independent reviewers (Z.L. and L.Z.) conducted a search of Medline, Embase, the Cochrane Library, Google Scholar and relevant journals. Only studies published in English were included in the meta-analysis. We performed the last updated search on August 2018. The following text words and corresponding heading terms were used as search terms: “computed tomography”, “CT”, “bowel obstruction”, “small bowel obstruction”, “intestinal obstruction” and “small intestinal obstruction”. The MeSH terms and keywords used for the search are listed in S2 Table. Related articles and reference lists were manually searched to avoid omissions. After title screening, we evaluated abstracts for relevance and identified articles as included, excluded or requiring further assessment. At this stage, if a paper required further assessment, we contacted the study lead investigator by e-mail with a request for further information.

2). Data extraction.

The inclusion criteria were as follows: (a) original research focusing on the diagnostic value of CT in SBO; (b) CT as diagnostic index test; and (c) sufficient data available to calculate construct 2×2 contingency tables and corresponding 95% confidence interval (95% CI). The following exclusion criteria were used: (a) index test and reference standard were both used in CT; (b) reviews of the literature; (c) nonhuman studies; (d) not published in English. For studies reporting the same or overlapping data by the same authors, the most suitable studies with the largest number of cases or latest publication dates were selected. Two investigators (Z.L. and L.Z.) assessed each study independently and recorded eligibility, quality and outcomes. Disagreements regarding eligibility were noted in 5% of the articles (κ = 0.89), which were resolved by a third party through consensus. A third investigator (F.Y.) provided arbitration in case of disagreement.

We extracted the following study features: (a) study design and patient characteristics (i.e., first author, year of publication, country of origin, department of the first author, consecutive recruitment, number of patients, age, sex ratio, and inclusion criteria); (b) imaging techniques (i.e., CT type, collimation, slice thickness, and use of contrast agent); (c) image evaluation (i.e., number of readers, retrospective or prospective CT reading, consensus reading, and interests of diagnosis); (d) reference standard (i.e., time between admission and surgery, histopathologic analysis, surgery findings, and duration of the medical follow-up).

3). Quantitative data synthesis.

Independently and in duplicate, reviewers assessed the risk of bias using the tool of the second edition of the Quality Assessment of Diagnostic Accuracy Studies (QUADAS 2) [31] using Review Manager 5.3 (RevMan, The Cochrane Collaboration, Oxford, United Kingdom). The QUADAS 2 consisted of four key domains that discuss patient selection, index test, reference standard and flow of patients through the study and timing of the index tests and reference standard (flow and timing). Each domain was assessed in terms of the risk of bias, and the first three domains were also assessed in terms of concerns about applicability. For each included study, a description, a comment, and a judgment as “high”, “unclear”, or “low” risk of bias were provided for each of the domains. Studies with high risk of bias for any one or more key domains were considered to exhibit high risk of bias. Studies with low risk of bias for all key domains were considered to exhibit low risk of bias. Otherwise, studies were considered to exhibit an unclear risk of bias. We classified high risk of bias studies as low-quality studies, and the other studies were classified as high-quality studies.

The data of the two-by-two tables were used to calculate sensitivity and specificity of each study. We present individual study results graphically by plotting the estimates of sensitivity and specificity (and their 95% confidence interval [CI]) based on forest plots using bivariate random-effects and summary receiver operating characteristic curve models (SROC) [32, 33]. Heterogeneity was evaluated using the Cochrane Q test and the I2 statistic to assess the degree of inter-study variation. I2 values of 0 to 24.9%, 25 to 49.9%, 50 to 74.9%, and 75 to 100% were considered to indicate no, mild, moderate, and significant thresholds for statistical heterogeneity, respectively [34, 35]. Subgroup analyses were performed based on age (adult or pediatric), publication year (2000 as cutoff point), different imaging techniques (enhanced CT or not; slice thickness ≤5 mm or >5 mm) and different causes of SBO using meta-regression analysis.

We used the Deek funnel plot asymmetry test, which is the recommended tool for assessing risk of publication bias in meta-analyses of diagnostic test accuracy [36]. A P-value less than 0.10 for the slope coefficient indicated significant asymmetry. P-values less than or equal to 0.05 were considered indicative of a significant difference. Analyses were performed with “midas” modules in the Stata software (version 12.0; StataCorp, College Station, Tex).

Results

Eligible studies

The study selection process is presented in Fig 1. The literature search yielded 1196 potentially relevant records. We removed 571 duplicate studies after screening the titles. After evaluating the abstract of each study, 533 studies were excluded because they did not meet the inclusion criteria. Subsequently, we carefully read the full text of each of the remaining 92 studies and excluded 47 studies for the following reasons: no relevant data (n = 37), not published in English (n = 7), overlapping data (n = 2) and review (n = 1). Finally, 45 studies were included in the meta-analysis.

thumbnail
Download:
Fig 1. Flow chart of selection of studies.

https://doi.org/10.1371/journal.pone.0226740.g001

As shown in Table 1, the eligible studies were conducted from 1992 through 2018 with a total number of 4004 patients, and the sample size ranged from 20 to 256. All 45 studies focused on the diagnostic value of CT for SBO. Among them, 24 studies were from North America, 13 were from Asia and 8 were from Europe. A variety of outcomes were recorded in these studies, including diagnosis of SBO (n = 19), ischemia (n = 17), predicting surgical intervention (n = 7), etiology (n = 16) and transition point (n = 11).

thumbnail
Download:
Table 1. Key parameters extracted from the included studies.

https://doi.org/10.1371/journal.pone.0226740.t001

Assessment of methodological quality

The summary and details of risk of bias were summarized in Fig 2 and S1 File. In summary, twelve (27%) studies that fulfilled all of the methodological criteria were judged to be at low risk of bias, and 20 (44%) exhibited high risk of bias. The remaining 13 (28%) were judged to be at unclear risk of bias. Among included studies, 6 (13%) studies had a high risk in the domain of patient selection given that the selection was based on specific or nonexhaustive causes of SBO. There was a high risk of bias with the index test in 7 (16%) studies that did not report information on CT performance parameters or reader number and expertise. In addition, most (93%) of included studies had a retrospective design, and 17 (38%) of these studies did not provide any information about whether the results of the reference standard were blinded to readers. Thus, the diagnostic performance of CT could have been overestimated. Only 15 (33%) studies reported an acceptable delay between index test and reference standard, and the other studies were considered to have a high risk or potential risk of flowing and timing bias due to unclear intervals. Meta-regression was performed to compare the different qualities of included studies.

thumbnail
Download:
Fig 2. Quality assessment for risk of bias and applicability of included studies: QUADAS evaluation.

https://doi.org/10.1371/journal.pone.0226740.g002

Value of CT in diagnosis of SBO

Overall, nineteen studies including 1269 patients reported data on diagnostic performance of CT on SBO. As shown in Fig 3, summary analysis results showed the sensitivity and specificity of CT for SBO were 91% (95% CI: 84%, 95%) and 89% (95% CI: 81%, 94%), respectively, and there significant heterogeneity (I2>75%) was noted. The SROC demonstrated an area under the curve of 0.96 (95% CI: 0.93, 0.97). Subgroup analysis results using meta-regression are presented in Table 2. There was no difference in diagnostic value of CT for SBO between adult and pediatric patients (sensitivity 89% vs. 96%, P = 0.12; specificity 86% vs. 90%, P = 0.08). Unenhanced CT was associated with a similar diagnostic value for SBO compared with enhanced CT. In addition, similar results were found between different slice thicknesses (≤5 mm or >5 mm), different study qualities (high or low quality) or publication year (<2000 or ≥2000).

thumbnail
Download:
Fig 3. Value of CT in diagnosis of SBO.

https://doi.org/10.1371/journal.pone.0226740.g003

thumbnail
Download:
Table 2. Pooled estimates of the diagnostic performance of CT in SBO and SBO with ischemia.

https://doi.org/10.1371/journal.pone.0226740.t002

Value of CT in diagnosis of ischemia

Seventeen studies (including 1575 patients) reported the value of CT in diagnosis of SBO with ischemia. The pooled sensitivity and specificity were 82% (95% CI: 67%, 91%) and 92% (95% CI: 86%, 95%), respectively, and there was significant heterogeneity (I2>75%) (Fig 4). The SROC demonstrated an area under the curve of 0.94 (95% CI: 0.92, 0.96). Only one study (18) reported the value of unenhanced CT in diagnosis of ischemia and the sensitivity and specificity were 64% and 93%. In subgroup analysis (Table 2), no difference was found between the enhanced and the unenhanced CT (sensitivity 83% vs. 64%, P = 0.23; specificity 92% vs. 93%, P = 0.79). However, higher sensitivity was found in adhesive SBO compared with routine causes (96% vs. 78%, P = 0.03), but the specificity was not significant (85% vs. 92%, P = 0.1). In addition, no difference was found between different study qualities (high or low quality) or publication year (<2000 or ≥2000).

thumbnail
Download:
Fig 4. Value of CT in diagnosis of ischemia.

https://doi.org/10.1371/journal.pone.0226740.g004

Value of CT in predicting surgical intervention

As shown in Fig 5, seven studies including 1094 patients presented the value of CT in predicting surgical intervention. Among them, 3 studies focused on adhesive SBO, and the other 4 studies focused on SBO with routine causes. The results of the summary analysis showed the sensitivity and specificity were 87% (95% CI: 68%, 95%) and 73% (95% CI: 55%, 85%), respectively, and there was significant heterogeneity (I2>75%). In subgroup analysis, higher sensitivity was found in adhesive SBO compared with routine causes (96% vs. 71%, P = 0.05), but the specificity was not significant (71% vs. 74%, P = 0.7).

thumbnail
Download:
Fig 5. Value of CT in predicting surgical intervention.

https://doi.org/10.1371/journal.pone.0226740.g005

Value of CT in etiology

Sixteen studies (including 961 patients) reported the value of CT in SBO etiology. The pooled sensitivity was 83% (95% CI: 76%, 88%), and there was significant heterogeneity (I2>75%). Subgroup analysis results using meta-regression were presented in Table 3. The pooled sensitivity values of CT for adhesion, hernia and tumor were 95% (I2 = 52%), 70% (I2 = 57%) and 82% (I2 = 37%), respectively.

thumbnail
Download:
Table 3. Sensitivity of CT in diagnosis of etiology in SBO.

https://doi.org/10.1371/journal.pone.0226740.t003

Value of CT in transition point diagnosis

Overall, eleven studies including 823 patients presented the value of CT in diagnosis of transition point of SBO. Summary analysis results showed that the sensitivity and specificity were 92% (95% CI: 87%, 95%) and 87% (95% CI: 74%, 95%), respectively, and significant heterogeneity was noted (I2>75%).

Publication bias

The impact of publication bias on meta-analysis results was assessed using Deeks’ funnel plots. The shapes of the funnel plots for the pooled sensitivity and specificity of CT performance for SBO revealed obvious symmetry (P = 0.64), indicating that the meta-analysis was not affected by publication bias (Fig 6).

thumbnail
Download:
Fig 6. Illustration of publication bias.

https://doi.org/10.1371/journal.pone.0226740.g006

Discussion

We performed a systematic review of the literature and identified 45 studies (more than 4000 patients) reporting the diagnostic performance of CT for SBO. The results of this study showed that CT should be the choice for the overall diagnosis of SBO, which has considerable accuracy in diagnosis of SBO, ischemia, predicting surgical intervention, etiology and transition point. Similar diagnostic value of CT for SBO was found between adult and pediatric patients. We also found that unenhanced CT had similar power in diagnosis of SBO compared with enhanced CT. In addition, CT was associated with higher sensitivity for ischemia in adhesive SBO compared with routine causes of SBO, but no difference in specificity was noted. Furthermore, regarding etiology, CT had significant sensitivity for adhesion identification.

Currently, plain film radiography (X-ray), CT, ultrasound and magnetic resonance imaging (MRI) are utilized as diagnostic modalities for suspected SBO. Due to easier accessibility and lower cost, plain film radiography (X-ray) is typically the initial imaging choice for the evaluation of SBO. However, this imaging modality is often nondiagnostic with poor sensitivity (46–69%) and specificity (57–67%) [37, 38]. In contrast, our study reported significant sensitivity and specificity of CT for SBO at 91% and 89%, respectively. Ultrasound also represents a convenient and inexpensive diagnostic tool that could be performed at bedside, especially in the emergency department. A recent meta-analysis identified 11 studies and reported a high sensitivity (92%) and specificity (97%) of ultrasound for SBO [39]. However, limited evidence is available for the use of ultrasound for diagnosis of small bowel ischemia, which is an important complication of SBO and an indication for emergency surgical intervention [40]. Thus, CT, rather than X-ray or ultrasound, was recommended as the first choice in the overall diagnosis of SBO [67, 68].

As reported in our study, CT played a key role in the diagnosis of SBO and the diagnosis of small bowel ischemia. Many CT findings, such as decreased enhanced bowel wall, wall thickness, mesenteric congestion, mesenteric fluid, and peritoneal fluid, had been reported as findings related to bowel ischemia [8, 23, 24, 26, 41]. A previous meta-analysis [42] including nine studies reported that a hypoenhanced bowel wall (specificity 95%) was highly predictive of ischemia, and the absence of mesenteric fluid (sensitivity 89%) was a reliable finding to exclude strangulation. A recent study including 256 patients with adhesive SBO found that peritoneal fluid (sensitivity 89%) instead of mesenteric fluid (sensitivity 73%) had the highest sensitivity among CT findings, and hypoenhanced bowel wall, free peritoneal gas, pneumatosis or venous gas were all associated with high specificity (96–99%) [43].

Several studies [6, 18, 24] focused on the diagnostic value of unenhanced CT for SBO, which might be more safer for the patients with the high risk of contrast agent-induced nephropathy [69]. Atri et al [6] reported that unenhanced CT had similar accuracy to diagnose mechanical small bowel obstruction compared with enhanced CT. For ischemia, a retrospective study [18] showed that increased bowel-wall attenuation on unenhanced images had 100% specificity and 56% sensitivity. Furthermore, a recent study [24] found that the addition of unenhanced CT to contrast-enhanced CT could improve the sensitivity, diagnostic confidence, and observer agreement for the diagnosis of ischemia. However, due to the few evidence, the effect of unenhanced CT for ischemia should be reconfirmed in the future. Although similar diagnostic power between unenhanced and enhanced CT was found for SBO in this review, enhanced CT might be more powerful in the diagnosis of ischemia, etiology and predicting surgical intervention [67, 68].

In addition, a few studies [44–46] reported the diagnostic value of MRI for patients with suspected SBO, especially for pregnant women. A small observational study [44] reported that cine MRI was a feasible and promising technique for diagnosing strangulation of SBO with high sensitivity (100%) and specificity (93%). However, compared with CT, MRI might not be convenient (especially at night), has a longer scan time, and might not be as reliable in identifying the etiology of SBO [67].

This study first comprehensively evaluated the diagnostic utility of CT for SBO, including multiple relevant outcomes, such as diagnostic accuracy, ischemia, predicting surgical intervention, etiology and transition point. This study included data from more than 4,000 patients, 45 studies, and 13 countries from different regions of North America, Asia and Europe. Two independent investigators also rigorously assessed its methodological quality.

However, this systematic review and meta-analysis has several limitations. First, most (93.3%) of included studies were retrospective studies, which may overestimate the diagnostic value of CT, thus, high-quality prospective studies are needed in the future. Second, 66% of included studies are considered to exhibit a high risk or potential risk of flowing and timing bias due to an unclear interval between index test and reference standard with significant heterogeneities of primary outcomes. However, similar outcomes was found in the subgroup analysis of high-quality included studies. Third, data are limited with respect to the pediatric population, limiting applicability to this subgroup. Fourth, the literature on the use of unenhanced CT for ischemia is also limited (only one study included), highlighting the need for future investigations on this topic. Finally, although no publication bias was found in this meta-analysis, only published studies with selective databases were included for analysis, and the unavailability of unreported outcomes could have resulted in reporting bias. Regardless of these limitations, we sought to minimize bias throughout our study by using strict method identification, data selection, and statistical analysis, as well as controlling for publication bias and performing sensitivity analyses.

Conclusion

This meta-analysis suggests that CT has considerable accuracy in diagnosis of SBO, ischemia, predicting surgical intervention, etiology and transition point. Further large-sample, high-quality prospective studies focusing on the performance of unenhanced CT for SBO with ischemia are needed.

Supporting information

S1 Table. PRISMA checklist.

https://doi.org/10.1371/journal.pone.0226740.s001

(DOCX)

S2 Table. Characteristics of the computed-assisted literature search strategy.

https://doi.org/10.1371/journal.pone.0226740.s002

(DOCX)

S1 File. Methodological criteria of the included studies: QUADAS evaluation.

https://doi.org/10.1371/journal.pone.0226740.s003

(TIF)

References

  1. 1. Nicolaou S, Kai B, Ho S, Su J, Ahamed K. Imaging of acute small-bowel obstruction. AJR Am J Roentgenol. 2005;185(4):1036–1044. pmid:16177429
  2. 2. Hastings RS, Powers RD. Abdominal pain in the ED: a 35 year retrospective. Am J Emerg Med. 2011;29(7):711–6. pmid:20825873
  3. 3. Paulson EK, Thompson WM. Review of small-bowel obstruction: the diagnosis and when to worry. Radiology. 2015;275(2):332–42. pmid:25906301
  4. 4. Taylor MR, Lalani N. Adult small bowel obstruction. Acad Emerg Med. 2013;20(6):528–44. pmid:23758299
  5. 5. Ros PR, Huprich JE. ACR Appropriateness Criteria on suspected small-bowel obstruction. J Am Coll Radiol. 2006;3(11):838–41. pmid:17412182
  6. 6. Atri M, McGregor C, McInnes M, Power N, Rahnavardi K, Law C, et al. Multidetector helical CT in the evaluation of acute small bowel obstruction: comparison of non-enhanced (no oral, rectal or IV contrast) and IV enhanced CT. Eur J Radiol. 2009;71(1):135–40. pmid:18534800
  7. 7. Balthazar E, Birnbaum B, Megibow A, Gordon R, Whelan C, Hulnick D. Closed-loop and strangulating intestinal obstruction: CT signs. Radiology. 1992;185(3):769–75. pmid:1438761
  8. 8. Balthazar EJ, Liebeskind ME, Macari M. Intestinal ischemia in patients in whom small bowel obstruction is suspected: evaluation of accuracy, limitations, and clinical implications of CT in diagnosis. Radiology. 1997;205(2):519–22. pmid:9356638
  9. 9. Chang WC, Ko KH, Lin CS, Hsu HH, Tsai SH, Fan HL, et al. Features on MDCT that predict surgery in patients with adhesive-related small bowel obstruction. PloS One. 2014;9(2):e89804. pmid:24587047
  10. 10. Daneshmand S, Hedley CG, Stain SC. The utility and reliability of computed tomography scan in the diagnosis of small bowel obstruction. Am Surg. 1999;65(10):922–6. pmid:10515535
  11. 11. Deshmukh SD, Shin DS, Willmann JK, Rosenberg J, Shin L, Jeffrey RB. Non-emergency small bowel obstruction: assessment of CT findings that predict need for surgery. Eur Radiol. 2011;21(5):982–6. pmid:20963444
  12. 12. Donckier V, Closset J, Van Gansbeke D, Zalcman M, Sy M, Houben JJ, et al. Contribution of computed tomography to decision making in the management of adhesive small bowel obstruction. Br J Surg. 1998;85(8):1071–4. pmid:9717999
  13. 13. Duda JB, Bhatt S, Dogra VS. Utility of CT whirl sign in guiding management of small-bowel obstruction. AJR Am J Roentgenol. 2008;191(3):743–7. pmid:18716103
  14. 14. Filippone A, Cianci R, Grassedonio E, Di Fabio F, Storto ML. Four-section multidetector computed tomographic imaging of bowel obstruction: usefulness of axial and coronal plane combined reading. J Comput Assist Tomogr. 2007;31(4):499–507. pmid:17882022
  15. 15. Frager D, Baer JW, Medwid SW, Rothpearl A, Bossart P. Detection of intestinal ischemia in patients with acute small-bowel obstruction due to adhesions or hernia: efficacy of CT. AJR Am J Roentgenol. 1996;166(1):67–71. pmid:8571907
  16. 16. Frager D, Medwid SW, Baer JW, Mollinelli B, Friedman M. CT of small-bowel obstruction: value in establishing the diagnosis and determining the degree and cause. AJR Am J Roentgenol. 1994;162(1):37–41. pmid:8273686
  17. 17. Fukuya T, Hawes DR, Lu CC, Chang PJ, Barloon TJ. CT diagnosis of small-bowel obstruction: efficacy in 60 patients. AJR Am J Roentgenol. 1992;158(4):765–9; discussion 71–2. pmid:1546591
  18. 18. Geffroy Y, Boulay-Coletta I, Julles MC, Nakache S, Taourel P, Zins M. Increased unenhanced bowel-wall attenuation at multidetector CT is highly specific of ischemia complicating small-bowel obstruction. Radiology. 2014;270(1):159–67. pmid:24029649
  19. 19. Peck JJ, Milleson T, Phelan J. The role of computed tomography with contrast and small bowel follow-through in management of small bowel obstruction. Am J Surg. 1999;177(5):375–8. pmid:10365873
  20. 20. Walsh DW, Bender GN, Timmons H. Comparison of computed tomography-enteroclysis and traditional computed tomography in the setting of suspected partial small bowel obstruction. Emerg Radiol. 1998;5(1):29–37.
  21. 21. Wang Q, Chavhan GB, Babyn PS, Tomlinson G, Langer JC. Utility of CT in the diagnosis and management of small-bowel obstruction in children. Pediatr Radiol. 2012;42(12):1441–8. pmid:23052726
  22. 22. Yaghmai V, Nikolaidis P, Hammond NA, Petrovic B, Gore RM, Miller FH. Multidetector-row computed tomography diagnosis of small bowel obstruction: can coronal reformations replace axial images? Emerg Radiol. 2006;13(2):69–72. pmid:16941110
  23. 23. Chang YJ, Yan DC, Lai JY, Chao HC, Chen CL, Chen SY, et al. Strangulated small bowel obstruction in children. J Pediatr Surg. 2017;52(8):1313–7. pmid:28318600
  24. 24. Chuong AM, Corno L, Beaussier H, Boulay-Coletta I, Millet I, Hodel J, et al. Assessment of Bowel Wall Enhancement for the Diagnosis of Intestinal Ischemia in Patients with Small Bowel Obstruction: Value of Adding Unenhanced CT to Contrast-enhanced CT. Radiology. 2016;280(1):98–107. pmid:26866378
  25. 25. Kim JH, Ha HK, Kim JK, Eun HW, Park KB, Kim BS, et al. Usefulness of known computed tomography and clinical criteria for diagnosing strangulation in small-bowel obstruction: analysis of true and false interpretation groups in computed tomography. World J Surg. 2004;28(1):63–8. pmid:14648046
  26. 26. Sheedy SP, Earnest Ft, Fletcher JG, Fidler JL, Hoskin TL. CT of small-bowel ischemia associated with obstruction in emergency department patients: diagnostic performance evaluation. Radiology. 2006;241(3):729–36. pmid:17114622
  27. 27. Hwang JY, Lee JK, Lee JE, Baek SY. Value of multidetector CT in decision making regarding surgery in patients with small-bowel obstruction due to adhesion. Eur Radiol. 2009;19(10):2425–31. pmid:19415288
  28. 28. Pricolo VE, Curley F. CT scan findings do not predict outcome of nonoperative management in small bowel obstruction: Retrospective analysis of 108 consecutive patients. Int J Surg. 2016;27:88–91. pmid:26808325
  29. 29. Li Zhengyan, Song Bin. Diagnostic utility of CT for small bowel obstruction: systematic review and meta-analysis. PROSPERO. 2015; CRD42015024658 Available from http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42015024658.
  30. 30. Moher D, Liberati A, Tetzlaff J, Altman DG, Group P. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. BMJ. 2009;339:b2535. pmid:19622551
  31. 31. Whiting PF, Rutjes AW, Westwood ME, Mallett S, Deeks JJ, Reitsma JB, et al. QUADAS-2: a revised tool for the quality assessment of diagnostic accuracy studies. Ann Intern Med. 2011;155(8):529–36. pmid:22007046
  32. 32. Reitsma JB, Glas AS, Rutjes AW, Scholten RJ, Bossuyt PM, Zwinderman AH. Bivariate analysis of sensitivity and specificity produces informative summary measures in diagnostic reviews. J Clin Epidemiol. 2005;58(10):982–90. pmid:16168343
  33. 33. Jones CM, Athanasiou T. Summary receiver operating characteristic curve analysis techniques in the evaluation of diagnostic tests. Ann Thorac Surg. 2005;79(1):16–20. pmid:15620907
  34. 34. Higgins JP, Thompson SG. Quantifying heterogeneity in a meta-analysis. Stat Med. 2002;21(11):1539–58. pmid:12111919
  35. 35. Higgins JP, Thompson SG, Deeks JJ, Altman DG. Measuring inconsistency in meta-analyses. BMJ. 2003;327(7414):557–60. pmid:12958120
  36. 36. 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. pmid:16085191
  37. 37. Jang TB, Schindler D, Kaji AH. Bedside ultrasonography for the detection of small bowel obstruction in the emergency department. Emergency medicine journal: EMJ. 2011;28(8):676–8. pmid:20732861
  38. 38. Maglinte DD, Reyes BL, Harmon BH, Kelvin FM, Turner WW Jr, Hage JE, et al. Reliability and role of plain film radiography and CT in the diagnosis of small-bowel obstruction. AJR Am J Roentgenol. 1996;167(6):1451–5. pmid:8956576
  39. 39. Gottlieb M, Peksa GD, Pandurangadu AV, Nakitende D, Takhar S, Seethala RR. Utilization of ultrasound for the evaluation of small bowel obstruction: A systematic review and meta-analysis. Am J Emerg Med. 2018;36(2):234–42. pmid:28797559
  40. 40. Wale A, Pilcher J. Current Role of Ultrasound in Small Bowel Imaging. Semin Ultrasound CT MR. 2016;37(4):301–12. pmid:27342894
  41. 41. Zalcman M, Sy M, Donckier V, Closset J, Gansbeke DV. Helical CT signs in the diagnosis of intestinal ischemia in small-bowel obstruction. AJR Am J Roentgenol. 2000;175(6):1601–7. pmid:11090385
  42. 42. Millet I, Taourel P, Ruyer A, Molinari N. Value of CT findings to predict surgical ischemia in small bowel obstruction: A systematic review and meta-analysis. Eur Radiol. 2015;25(6):1823–35. pmid:25850889
  43. 43. Millet I, Boutot D, Faget C, Pages-Bouic E, Molinari N, Zins M, et al. Assessment of Strangulation in Adhesive Small Bowel Obstruction on the Basis of Combined CT Findings: Implications for Clinical Care. Radiology. 2017;285(3):798–808. pmid:28759326
  44. 44. Takahara T, Kwee TC, Haradome H, Aoki K, Matsuoka H, Nakamura A, et al. Peristalsis gap sign at cine magnetic resonance imaging for diagnosing strangulated small bowel obstruction: feasibility study. Jpn J Radiol. 2011;29(1):11–8. pmid:21264656
  45. 45. Rubio EI, Blask AR, Badillo AT, Bulas DI. Prenatal magnetic resonance and ultrasonographic findings in small-bowel obstruction: imaging clues and postnatal outcomes. Pediatr Radiol. 2017;47(4):411–21. pmid:28116474
  46. 46. Krishna S, McInnes MDF, Schieda N, Narayanasamy S, Sheikh A, Kielar A. Diagnostic Accuracy of MRI for Diagnosis of Internal Hernia in Pregnant Women With Prior Roux-en-Y Gastric Bypass. AJR Am J Roentgenol. 2018;211(4):755–9. pmid:30106618
  47. 47. Halepota HF, Mateen Khan MA, Shahzad N. Sensitivity and specificity of CT scan in small bowel obstruction among children. J Pak Med Assoc. 2018;68(5):744–6. pmid:29885174
  48. 48. He B, Gu J, Huang S, Gao X, Fan J, Sheng M, et al. Diagnostic performance of multi-slice CT angiography combined with enterography for small bowel obstruction and intestinal ischaemia. J Med Imaging Radiat Oncol. 2017;61(1):40–7. pmid:27709810
  49. 49. Idris M, Kashif N, Idris S, Memon WA, Tanveer UH, Haider Z. Accuracy of 64-slice multidetector computed tomography scan in detection of the point of transition of small bowel obstruction. Pediatr Radiol. 2012;30(3):235–41.
  50. 50. Jabra AA, Fishman EK. Small bowel obstruction in the pediatric patient: CT evaluation. Abdom Imaging. 1997;22(5):466–70. pmid:9233878
  51. 51. Jabra AA, Eng J, Zaleski CG, Abdenour GE Jr, Vuong HV, Aideyan UO, et al. CT of small-bowel obstruction in children: sensitivity and specificity. AJR Am J Roentgenol. 2001;177(2):431–6. pmid:11461877
  52. 52. Jaffe TA, Martin LC, Thomas J, Adamson AR, DeLong DM, Paulson EK. Small-bowel obstruction: coronal reformations from isotropic voxels at 16-section multi-detector row CT. Radiology. 2006;238(1):135–42. pmid:16293807
  53. 53. Jancelewicz T, Vu LT, Shawo AE, Yeh B, Gasper WJ, Harris HW. Predicting strangulated small bowel obstruction: an old problem revisited. J Gastrointest Surg. 2009;13(1):93–9. pmid:18685902
  54. 54. Jang KM, Min K, Kim MJ, Koh SH, Jeon EY, Kim IG, et al. Diagnostic performance of CT in the detection of intestinal ischemia associated with small-bowel obstruction using maximal attenuation of region of interest. AJR Am J Roentgenol. 2010;194(4):957–63. pmid:20308497
  55. 55. Kato K, Mizunuma K, Sugiyama M, Sugawara S, Suzuki T, Tomabechi M, et al. Interobserver agreement on the diagnosis of bowel ischemia: assessment using dynamic computed tomography of small bowel obstruction. Jpn J Radiol. 2010;28(10):727–32. pmid:21191737
  56. 56. Kulvatunyou N, Pandit V, Moutamn S, Inaba K, Chouliaras K, DeMoya M, et al. A multi-institution prospective observational study of small bowel obstruction: Clinical and computerized tomography predictors of which patients may require early surgery. J Trauma Acute Care Surg. 2015;79(3):393–8. pmid:26307871
  57. 57. Maglinte DD, Gage SN, Harmon BH, Kelvin FM, Hage JP, Chua GT, et al. Obstruction of the small intestine: accuracy and role of CT in diagnosis. Radiology. 1993;188(1):61–4. pmid:8511318
  58. 58. Makanjuola D. Computed tomography compared with small bowel enema in clinically equivocal intestinal obstruction. Clin Radiol. 1998;53(3):203–8. pmid:9528871
  59. 59. Matsushima K, Inaba K, Dollbaum R, Cheng V, Khan M, Herr K, et al. High-Density Free Fluid on Computed Tomography: a Predictor of Surgical Intervention in Patients with Adhesive Small Bowel Obstruction. J Gastrointest Surg. 2016;20(11):1861–6. pmid:27613731
  60. 60. Memon W, Khattak YJ, Alam T, Sconfienza LM, Awais M, Anwar SSM. MDCT of small bowel obstruction: How reliable are oblique reformatted images in localizing point of transition? Gastroenterol Res Pract. 2014:815802. pmid:24883057
  61. 61. Obuz F, Terzi C, Sokmen S, Yilmaz E, Yildiz D, Fuzun M. The efficacy of helical CT in the diagnosis of small bowel obstruction. Eur J Radiol. 2003;48(3):299–304. pmid:14652150
  62. 62. Pongpornsup S, Tarachat K, Srisajjakul S. Accuracy of 64 sliced multi-detector computed tomography in diagnosis of small bowel obstruction. J Med Assoc Thai. 2009;92(12):1651–61. pmid:20043569
  63. 63. Scrima A, Lubner MG, King S, Pankratz J, Kennedy G, Pickhardt PJ. Value of MDCT and Clinical and Laboratory Data for Predicting the Need for Surgical Intervention in Suspected Small-Bowel Obstruction. AJR Am J Roentgenol. 2017;208(4):785–93. pmid:28328258
  64. 64. Shah ZK, Uppot RN, Wargo JA, Hahn PF, Sahani DV. Small bowel obstruction: the value of coronal reformatted images from 16-multidetector computed tomography—a clinicoradiological perspective. J Comput Assist Tomogr. 2008;32(1):23–31. pmid:18303284
  65. 65. Taourel PG, Fabre JM, Pradel JA, Seneterre EJ, Megibow AJ, Bruel JM. Value of CT in the diagnosis and management of patients with suspected acute small-bowel obstruction. AJR Am J Roentgenol. 1995;165(5):1187–92. pmid:7572500
  66. 66. Xu N, Li NE, Cao XL, Wang L, Li XT, Huang LY. The benefit of double-balloon enteroscopy combined with abdominal contrast-enhanced CT examination for diagnosing small-bowel obstruction. Acta Endoscopica. 2013;43(5–6):242–7.
  67. 67. Ten Broek RPG, Krielen P, Di Saverio S, Coccolini F, Biffl WL, Ansaloni L, et al. Bologna guidelines for diagnosis and management of adhesive small bowel obstruction (ASBO): 2017 update of the evidence-based guidelines from the world society of emergency surgery ASBO working group. World J Emerg Surg. 2018;13:24. pmid:29946347
  68. 68. Maung AA, Johnson DC, Piper GL, Barbosa RR, Rowell SE, Bokhari F, et al. Evaluation and management of small-bowel obstruction: an Eastern Association for the Surgery of Trauma practice management guideline. J Trauma Acute Care Surg. 2012;73(5 Suppl 4):S362–9.
  69. 69. Garfinkle MA, Stewart S, Basi R. Incidence of CT Contrast Agent-Induced Nephropathy: Toward a More Accurate Estimation. AJR Am J Roentgenol. 2015;204(6):1146–51. pmid:26001222