Imaging decisions in paediatric trauma

The Royal College of Radiologists (RCR) have recently published a brand new 2024 guideline for imaging in paediatric trauma – updated from the last RCR guidance from 2014. We reviewed the previous guidance here.

For those who haven’t seen it yet, the document is easily found on the RCR website, and is helpfully quite short and easy to read (1).

Previous RCR guidance from 2014 was the first paediatric-specific guideline for imaging in trauma patients. We knew at this point that when compared with adults, paediatric trauma incidence was relatively low, injury patterns were different, and ionising radiation shown to be more harmful to children (2). Their tissues are more radio-sensitive, and they are more likely to live long enough to develop radiation-induced cancers. Hence the principle of ALARP (as low as reasonably practicable) for ionizing radiation is even more important in children than adults.

Data from Trauma Audit Research Network (TARN) showed that paediatric major trauma centres order less whole-body CT scans than the national average, without any difference in adverse final outcomes (3). Therefore, the adult trauma approach of “whole body CT trauma survey” should not be applied to children. Emphasis should be aimed at careful and competent clinical assessment, good knowledge of paediatric injury patterns of different age groups, judicious use of plain film x-rays and targeted CT if clinically indicated (2). Repeated clinical assessment for areas not imaged is also useful when managing injured children.

Spoiler alert!: The new guidance on blunt trauma is very similar – but there are some valuable new algorithms, and some interesting new sections on penetrating trauma, blast injury and chest imaging in blunt trauma.

So what’s new…?

Blunt trauma

The newest guidance on recommended imaging is very similar to 2014, apart from in chest injury. Which makes my job easier…

If you want to refresh your knowledge on imaging in paediatric patients, then please visit this link (1).

New advice on imaging of the chest in trauma now recommends considering contrast-enhanced CT thorax in the following scenarios; rapid deceleration injury (defined as fall >6 metres), high-impact motor vehicle crash (>40mph), intoxication, reduced GCS or distracting injury. This is converse to the previous advice for paediatric trauma patients, to try and avoid CT if chest x-ray is normal, patient is stable and conscious. This new guidance has based around the NEXUS chest CT decision instrument which has been validated for adults and children >14yrs (4).

There is also a very useful new tool aimed at helping clinicians to take a more focused approach to CT scanning in children.

As per previous, mixed and adult trauma centres tend to order more CT scans for children. Evidence shows that adolescent trauma patient’s treated in mixed and adult major trauma centres had higher 30-day mortality rates, with generally higher rates of CT scan requesting (5).

The new algorithm …coming to a resus wall near you… gives us with a quick and useful checklist to aid with the decision of “does this child need a CT?” (1).

CT scan exclusion tool for blunt poly-trauma in under 16s

Not scanning that anatomical region should be considered if an anatomical region satisfies all the criteria.
Senior clinical discretion is still advised.

Head
a.	Not reduced GCS below 13 or intubated
b.	Did not trigger NICE guideline
Neck
a.	Not reduced GCS below 13 or intubated
b.	Did not trigger NICE guideline
Chest
a.	Chest X-ray normal
b.	Chest exam normal
c.	Not rapid deceleration (defined as fall >6 metes or high impact MVC >40mph)
Abdomen
a.	No lap belt or handlebar injuries
b.	No abdominal wall bruising
c.	No abdominal tenderness in a conscious patient
d.	No abdominal distention
e.	No evidence clinically of persiostent hypotension, e.g. unexplained tachycardia
f.	No blood from rectum or NG tube
Spine
a.	No midline tenderness
b.	Low level of concern mechanism
c.	No neurology (MRI should be used as first line)
(MRI should be used where possible as first line)
Limbs
a.	No complex fractures (consider)
b.	No concern for vascular injury (consider)
Wider concerns, which could lower the threshold to CT scan:
a.	Patient needs emergency operation
b.	Patient has long secondary transfer
c.	Patient will be sedated in critical care area for an extended period

Source from (1)

Penetrating trauma

New to the 2024 guideline is a section on advice for imaging in penetrating trauma, along with another helpful new algorithm. Penetrating trauma can be defined as an injury which breaches the skin – including but not limited to stabbing, ballistic injury and foreign body insertion. Post-contrast CT imaging is generally recommended as the modality of choice.

Chest and extremity radiographs are complementary and have a role in the acute presentation in the assessment of foreign body, fracture and pathology requiring immediate treatment such as haemo/pneumothorax. Dual-phase imaging would be recommended in the case of extremity injury where an arterial phase would be required, or in suspected central aortic injury.

However, before you get requesting, there are several important factors to consider first!

In penetrating trauma initial assessment may often underestimate depth, extent and number of injuries. In hypovolaemic patients it can also be difficult to assess the extent of injury, so it is recommended to assume a greater level of trauma rather than take a conservative approach. If a puncture site occurs at the junction of two body parts, eg. the neck and chest, wider CT coverage is required. Patient’s suffering trauma in complex circumstances, such as being stabbed, can often be less forthcoming with a true reflective history of mechanism of injury. Paediatric patients are also known to display an enhanced vasoconstriction response which can given falsely reassuring results in dual phase imaging for haemorrhage (1).

Therefore several considerations need to be made when deciding on CT coverage and timing of contrast injection. Each case should involve a senior discussion between emergency physician and radiologist. The algorithm is a helpful guide in making these decisions more straightforward.

Suggested algorithm for imaging of penetrating trauma in paediatric patients

* The need for CXR is a clinician-led decision based on factors such as history and examination findings, patient stability, need for intervention, availability of cross-sectional imaging, etc

† Bastion or modified Bastion protocol is considered the standard for contrast administration, although the choice between the two protocols would be based on local practice

‡ Consider CT angiogram in place of Bastion or modified Bastion protocol if arterial injury is suspected

§ A wider CT coverage rather than a single body part should be considered if the entry wound occurs at the junction of two body parts or if there was a possibility of a wound depth or trajectory crossing between two body parts

Source from (1)

Blast injuries

Another new section to the 2024 guidance involves suggested imaging choices for blast injuries. Specifically, the guidance aims to help in the use of imaging in major incidents, where multiple victims present to hospital in a short period of time. It combines lessons learned from recent major incidents including the Manchester Arena Attack in May 2017 (6).

Blast injuries are defined as physical trauma resulting from direct or indirect exposure to an explosion. The pattern of injury sustained will vary depending on several factors; including the nature of the explosive device, distance from the blast, location of the blast, and whether the blast results from an improvised explosive device (IED).

In mass casualty blast incidents, risk of death in children is as high, if not higher than adults – so this should be taken into account when prioritising imaging. Patients who are haemodynamically unstable should be prioritised for rapid plain film x-rays, then transfer to theatre, whilst CT is recommended in stable patients. The coverage of CT imaging in stable patients should be based upon number of areas of concern.

Crucially, avoid MRI in acute investigation of blast injury given the risk of ferrimagnetic properties of shrapnel!

Planning the first hours of these major incidents is fundamental for patient outcomes, but we must also remember to predict the needs in the days and weeks to follow. Rapid, unidirectional patient flow from emergency department to wards, ICU and theatres is crucial in order to use our finite resources as effectively as possible (1).

Imaging algorithm for paediatric blast injuries

Include areas where there are visible injuries (eg point of entry for possible shrapnel) to guide surgical exploration
1. Low threshold for wider CT coverage when injuries suspected in multiple regions (eg head, neck, abdomen and pelvis, bones, vascular injuries)
1. Provides a whole-body map of shrapnel location and distribution
1. Non-contrast for head, split bolus for chest, abdomen, pelvis and limbs
1. Used to plan management by interventional radiology

Matthew Gray