Imaging in paediatric trauma- what’s new?

It’s the first week of your new placement in the Emergency Department of a Paediatric Major Trauma Centre.

You’ve just finished discharging your third case of flu that day when the red phone rings – a 14-year-old child has been stabbed in the chest and is severely injured.

The nurse in charge has input out a major trauma alert, and the consultant has asked you to request the relevant bloods and imaging after the primary survey. The crew will arrive in 8 minutes.

Everyone is busily prepping for their trauma roles; where can you turn for help?

In October 2024, the Royal College of Radiologists (RCR) unveiled updated guidance on imaging in major paediatric trauma, replacing their previous 2014 “Paediatric Trauma Protocols”. This long-awaited update reflects advances in imaging technology, evolving clinical practice, and a growing emphasis on balancing diagnostic accuracy with minimising radiation exposure in children.

Over the past decade, the landscape of paediatric trauma in the UK has shifted significantly. Worryingly, there has been an 84.1% rise in hospital admissions for children under 16 following assaults with sharp objects. This mirrors an 89.0% increase in police-recorded offences involving knives or sharp instruments over the same period. These figures highlight an urgent need for trauma systems to adapt, ensuring that imaging strategies remain both effective and child-centred in an evolving clinical environment.

This shift in paediatric trauma patterns is reflected in the updated 2024 RCR guidance. In the 2014 version, penetrating trauma was mentioned just once—now, it has its own dedicated chapter. Alongside this, the new guidance introduces separate chapters on blunt trauma and blast injuries, acknowledging the evolving nature of serious paediatric trauma.

Each section is organised by anatomical area for ease of use, making it more accessible for clinicians in time-critical situations. The RCR has also introduced practical decision-support tools, including imaging algorithms and a CT exclusion tool for blunt polytrauma, to streamline decision-making while minimising unnecessary radiation exposure.

What is this guidance?

What is this guidance not?

This is not a rigid rulebook dictating exactly what imaging should be performed in every possible scenario.

Paediatric major trauma is complex, and no single guideline can capture every nuance. Instead, the guidance serves as a framework to support decision-making, recognising that each child is unique and must be assessed clinically on a case-by-case basis. Imaging decisions should always be guided by clinical judgement, the specifics of the injury, and discussion within the trauma team.

Does every child need a CT scan?

Absolutely not! The Royal College of Radiologists (RCR) strongly advocates for the ALARP principle—“as low as reasonably practicable”—when it comes to imaging in paediatric trauma. Children are more vulnerable to the effects of ionising radiation than adults, both because their tissues are more radiosensitive and because they have a longer lifespan in which radiation-related risks could manifest as disease.

The European EPI-CT study, which analysed over 650,000 patients, found a significant dose-response relationship between CT-related radiation exposure and brain cancer. This is just one of many studies highlighting the potential risks of unnecessary imaging. With this in mind, the first question should always be: “Does this child need imaging at all?” rather than defaulting to a pan-scan approach.

If imaging is required, the least harmful and most appropriate modality should be considered first—often plain radiographs rather than CT. However, unlike in adults, where focused abdominal sonography in trauma (FAST) is a useful decision-making tool, RCR does not recommend FAST in paediatric trauma. The concern is that unenhanced ultrasound can provide false reassurance, potentially leading to missed injuries and inappropriate management decisions.

Does this guidance apply to everyone?    

So, what’s changed in blunt trauma?

Most of the RCR’s recommendations for imaging in blunt trauma remain unchanged from the 2014 guidance. However, one of the key updates is in the approach to chest imaging. The new guidance now incorporates the NEXUS Chest decision rule, a tool designed to help determine when thoracic imaging is necessary following trauma. This rule has been validated in a study of over 9,500 patients over 14 years, offering a structured approach to identifying clinically significant thoracic injuries while avoiding unnecessary imaging.

There are seven criteria:

The study found that NEXUS Chest had a negative predictive value of 98.5% for ruling out thoracic injury and 99.9% for clinically major thoracic injury.

Here’s a brief summary of the other updates RCR has made for imaging in paediatric blunt trauma:

The updated blunt trauma guidance and ALARP principle have been streamlined into a new CT scan exclusion tool. Designed for use during the primary survey of a paediatric trauma patient, this tool helps identify which anatomical regions may not require irradiation, reducing unnecessary CT scans and limiting radiation exposure.

Of course, clinical discretion remains essential—no tool can replace the need for careful clinical assessment and team discussion when deciding on the most appropriate imaging for each child.

But what about my stabbing case?

Don’t worry. There’s a whole new section to guide you, along with a handy imaging algorithm.

In general, any body area with a puncture wound should be considered for post-contrast CT imaging. Unlike blunt trauma, where external signs often correlate with internal injury, penetrating trauma presents a unique challenge—it is difficult to determine wound trajectory based solely on external examination.

This is particularly important for injuries occurring at junctional areas, where one anatomical region transitions into another. For example, wounds at the base of the neck and upper third of the chest, or the lower chest and upper abdomen, require broader CT coverage to ensure that injuries extending across these regions are not missed. This approach acknowledges the unpredictability of wound paths and helps ensure potentially life-threatening injuries are identified and managed promptly.

While contrast-enhanced CT is the imaging modality of choice for most patients with penetrating trauma, there are specific situations where plain radiographs play a complementary role in the acute setting.

• Chest radiographs can be particularly useful for detecting foreign bodies and immediate life-threatening conditions such as pneumothorax or haemothorax, which may require urgent intervention.
• Extremity radiographs are valuable for identifying associated fractures and detecting retained foreign bodies, particularly when there is a risk of embedded metallic or other penetrating objects.

These targeted radiographs can provide rapid, accessible imaging to support clinical decision-making, especially when a focused assessment is required before proceeding to more comprehensive imaging.

You mentioned blast injuries?!

A new section in the RCR guidance covers blast injuries—a topic that will hopefully remain of theoretical interest to most clinicians. The management of blast injuries in the Emergency Department is inherently challenging and high-stress, not only due to the potential for multiple casualties arriving in rapid succession but also because of the complex and varied nature of these injuries.

Blast injuries can be categorised as follows:

• Primary blast injuries – Caused by the shock wave from the explosion, leading to damage in gas-containing organs such as the lungs, bowel, and middle ear.
• Secondary blast injuries – Result from shrapnel and debris, often leading to penetrating trauma.
• Tertiary blast injuries – Occur when the blast force throws a victim against a surface, causing blunt trauma and fractures.
• Quaternary blast injuries – Include burns, inhalational injuries, and other trauma-related complications that do not fall into the previous categories.

Given the unpredictability and severity of these injuries, early imaging plays a crucial role in identifying the full extent of trauma. The updated guidance provides structured recommendations to support rapid, effective decision-making when faced with these rare but high-consequence cases.

This chapter helpfully comes with an imaging algorithm to provide quick and essential information for managing several paediatric victims with multiple known and occult injuries who present in a short period to the hospital.

In most cases, some form of imaging will be necessary to guide further management—whether to plan surgical exploration and shrapnel removal in theatre or to determine the need for intensive care admission, particularly in cases of blast lung injury.

For haemodynamically unstable patients requiring immediate surgery, plain radiographs may be used for rapid assessment before transfer to theatre. However, MRI is strictly avoided, as shrapnel often contains ferromagnetic materials, posing a significant safety risk.

For the majority of patients, CT imaging is the modality of choice, carefully balancing the need for critical diagnostic information against the radiation burden. The threshold for wider CT coverage is intentionally low—any visible injury should be imaged to guide surgical planning. While whole-body CT topograms are radiation-intensive, they can provide a comprehensive map of shrapnel distribution, ensuring no significant injury is overlooked.