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Three Part Question

In [children with a clinical suspicion of pneumonia], is [a standard frontal view CXR as good as standard frontal and lateral views] at [diagnosis]?

Clinical Scenario

A 4-year-old boy presents to your local ED with a 72-hour history of mild fever and cough. While you order a CXR to confirm your suspected diagnosis of pneumonia, you remember that the radiology department of your hospital has introduced a policy to limit children radiographs to a single frontal view. You wonder if the omission of the lateral view will risk missing an infiltrate on your patient's X-ray.

Search Strategy

No BestBETs or critical appraisals were found on this topic. clinicaltrials.gov was searched for an ongoing trial on the topic: no trials were found.

Pubmed, Advanced search builder, date of searching––2 November 2016: ((‘pneumonia’[MeSH Terms] OR ‘pneumonia’[All Fields]) AND (((‘radiography’[Subheading] OR ‘radiography’ [All Fields] OR ‘radiography’[MeSH Terms]) OR (‘radiography’[Subheading] OR ‘radiography’[All Fields] OR ‘X-ray’[All Fields] OR ‘X-rays’[MeSH Terms] OR ‘X-rays’[All Fields])) OR radiograph[All Fields])) AND ((((‘pediatrics’[MeSH Terms] OR ‘pediatrics’[All Fields] OR ‘paediatric’[All Fields]) OR (‘pediatrics’[MeSH Terms] OR ‘pediatrics’[All Fields] OR ‘pediatric’[All Fields])) OR (‘child’[MeSH Terms] OR ‘child’ [All Fields] OR ‘children’ [All Fields])) AND lateral[All Fields])

Embase 1980–2016, Week 44: (exp pneumonia/ OR pneumonia.mp) .AND (CXR.mp. or exp thorax radiography/ AND lateral.mp.) limit 7 to (human and english language and (infant or child or preschool child <1 to 6 years> or school child <7 to 12 years> or adolescent <13 to 17 years>))

The Cochrane Library date of searching 2 November 2016: MeSH descriptor: [Pneumonia] explode all trees AND MeSH descriptor: [Radiography])

Search Outcome

The above searches yielded seven relevant papers, of which one was a systematic review that included four of the papers, leaving two additional relevant papers for analysis. The three papers are summarised in the table

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Rigsby et al. 2004 USA	1268 children with frontal and lateral chest radiographs reviewed separately by three paediatric radiologists at a metropolitan children's hospital. The interpretation of the frontal and lateral views was used as the gold standard for the diagnosis of pneumonia.	Retrospective cohort study (2b)	Sensitivity of the frontal views alone. Specificity of the frontal views alone.	85% 98%	Radiographs interpreted using a viewbox, which could prove to be less accurate than digital interpretation.
Lynch et al. 2004 Canada	570 patients aged 1–16 years old, undergoing frontal and lateral X-rays for the clinical suspicion of pneumonia at an urban paediatric ED. Randomised to interpretation of frontal view (group 1) or both views (group 2) by paediatric emergency physicians. Interpretation of at least two of three paediatric radiologists as the gold standard.	RCT (2b)	Sensitivity	91% vs 87%	216 patients excluded because of associated asthma exacerbation. 59 patients withdrew from the study after allocation of their groups, affecting randomization.
			Specificity	58% vs 57%
Lynch et al. 2003 Canada	4 studies (3 retrospective and 1 prospective, non-randomized trials) met the inclusion criteria, for a total of 1108 patients aged 0-17 years old with a clinical suspicion of pneumonia. The included studies compared the frontal view alone to both frontal and lateral views interpreted by radiologists and/or pediatricians.	Systematic review (2a)	Sensitivity and specificity the frontal view alone compared to both views for the diagnosis of pneumonia	Sensitivity 90%, Specificity 96%	Heterogeneous age of the populations and specific criteria used to diagnose pneumonia. In one of the studies, a single radiologist reviewed all the radiographs. All studies examined radiologists interpretation of the x-rays, limiting the generalizability of the results to the ED where clinicians have to base management on their own conclusions while definitive interpretation often comes hours to days later.
			Additional number of lateral x-ray necessary to diagnose a pneumonia (NNT)	NNT 38

Comment(s)

In a context where radiation exposure in children should be kept as low as reasonably achievable, questioning the diagnostic value of the lateral X-ray for pneumonia has been the point of interest of several studies. However, the radiation associated with a single lateral radiograph remains low, estimated around 0.08 mSv (Mettler et al 2008), which carries minimal additional lifetime cancer risks. Among the studies selected, the RCT by Lynch et al (2004) is the only paper looking at the diagnostic value of the lateral radiograph when interpreted directly by emergency physicians rather than radiologists, and failed to show any improvement with the two views. According to the literature reviewed, it is probable that lateral views will demonstrate additional pneumonias, especially non-lobar infiltrates and infections affecting the lower left lobe, but the clinical significance of these findings remains unclear.

Clinical Bottom Line

The addition of a lateral view does not appear to significantly improve the accuracy of pneumonia diagnosis in children by emergency physicians when compared with frontal view alone. However, additional infiltrates may be seen on lateral radiograph when interpreted by radiologists.

References

1. Rigsby CK, Strife JL, Johnson ND et al. Is the frontal radiograph alone sufficient to evaluate for pneumonia in children? Paediatr Radiol 2004;34:379–83.
2. Lynch T, Gouin S, Larson C et al. Does the lateral chest radiograph help paediatric emergency physicians diagnose pneumonia? A randomized clinical trial. Acad Emerg Med 2004;11:625–9.
3. Lynch T, Gouin S, Larson C et al. Should the lateral chest radiograph be routine in the diagnosis of pneumonia in children? A review of the literature. Pediatr Child Health 2003;8:566–8