Standard for skeletal surveys
in
suspected non-accidental injury (NAI) in children
Copied from the The
British Society of Paediatric Radiology website at www.bspr.org.uk
Introduction
A
skeletal survey is a series of radiographic images, which
encompass the entire skeleton or anatomical regions appropriate
for the clinical indications.
The radiographic skeletal survey is the principal radiological
investigation in suspected child abuse. It is frequently critical
to diagnosis and is frequently presented as evidence in child
protection cases, criminal proceedings and other types of
litigation.
The
standard is required to help advance the science of radiology and
to improve the quality of the radiology service to patients.
Indications
-
Suspected physical NAI in infants and young children. Occult
injury is rare > 3 yrs age.
-
To
exclude NAI in siblings (under 3 years of age) of children
with proven NAI.
Technical requirements for technique
-
Quality of equipment: radiographic equipment should include a
general purpose radiographic unit equipped with a small focal
spot.
-
Film requirements: a high contrast general film system
designed for extremity use with a speed of no more than 200
and a limiting resolution of at least 10 line pairs per
millimetre is required for all anatomical regions in infants.
Increasingly computed radiography systems are being used to
obtain X-rays on children. Suitable computed radiography
systems (including standard resolution imaging plates) may be
used for skeletal surveys if they have dedicated paediatric
software. Soft copy reporting is advisable to maximise the
image quality of the system. A low absorption cassette or
front plate is recommended to maximise radiographic detection.
These systems should be used without a grid. Beyond infancy,
faster general purpose systems will be required for the
thicker body regions e.g. lumbar spine.
-
Quality of imaging: the skeletal survey examination should be
performed in accordance with principles of high quality
diagnostic radiography. These include proper technique
factors, positioning, collimation, side markers, image
identification, restraining methods and patient shielding.
Personnel requirements
-
Radiographers trained in paediatric radiography techniques
should perform skeletal surveys in children.
-
Appropriately trained radiographic staff must be available in
all radiology departments where children are imaged.
Procedural standards
-
The areas that should be demonstrated will depend on the
particular clinical indication.
-
Suspected NAI: each anatomical area should be imaged with a
separate radiographic exposure to ensure uniform image density
and minimise image unsharpness.
-
X-rays should be exposed to show soft tissue and bone detail.
-
The limbs must be straight. Radiographs of each extremity
should be at least of the frontal projection. Radiographs of
the axial skeleton should be obtained in two projections if an
abnormality is suspected (see Table 1).
-
X-rays (in 2 projections) of acute injury e.g. a fractured
femur, should be done as an emergency as required. A skeletal
survey should be done on the next working day, not as an
emergency on call.
-
If
practical, the views of the lower legs should be obtained
before Gallows traction is applied. If this is not practical,
the lower limb x-rays can be obtained at a later time.
-
It
is important to obtain high quality radiographs for the
skeletal survey, which are best obtained in normal working
hours after the child has received adequate analgesia.
-
The paediatrician is responsible for explaining to the child’s
carers why a skeletal survey is necessary.
-
The skeletal survey should be performed by two people working
together, and with the child at all times. The films should
have the correct name and correct side markers, and the date
and time of the examination should be clearly marked.
-
The radiographer should sign the technical detail card. To
ensure continuity of evidence, the person (parent or nurse)
identifying the child to the radiographer should also sign the
technical detail record (1).
-
The radiographers should bring the films to a designated
consultant radiologist for immediate review so that further
views may be obtained as required.
-
The radiology report should document all sites of suspected or
definite abnormality. When patterns of injury raise strong
suspicion of NAI this should be stated in the report.
-
Doubtful areas should be commented upon and arrangements made
for further follow-up films. (eg an interval CXR at 2-3 weeks
may reveal healing rib fractures that were not identifiable on
the initial CXR, or periosteal reaction in a suspect long
bone).
-
Delayed films (1-2 weeks later) may be needed to help date
injuries.
-
The report should be communicated urgently to the referring
clinician.
Targets for outcome
There is insufficient good quality evidence to set a performance
target. A literature search through Medline and Embase revealed
one study containing relevant information (2). This study gives an
indication of the accuracy level that is attainable in
radiographic diagnosis of non-accidental injury in children. These
figures relate to screen-film radiography, not digital systems.
|
Outcome |
Indication |
(95% confidence intervals) |
|
Accuracy |
93% |
(88% to 98%) |
|
Sensitivity |
80% |
(75% to 85%) |
|
Specificity |
98% |
(95% to 100%) |
The
number of subjects is small (n=20) and the study population is not
representative of the clinical environment of radiographic
reporting by clinical radiologists. The study group is not
representative because 50% of the cases in the series were proven
to be child abuse. The percentage of child abuse cases is much
lower in clinical practice. Also there was no measure
of inter-observer variability in the study. The data required to
calculate the figures from the study were not published and cannot
be checked.
Future development
The
development of digital radiographic systems and PACS systems may
have an impact on some of the radiographic aspects of the
standard.
References
(1)
Guidance for the provision of forensic radiography services. 1999.
The college of radiographers. 2 Carriage Row, 183 Eversholt St.,
LONDON NW1 1BU
(2) Skeletal surveys for child abuse: comparison of interpretation
using digitised images and screen-film radiographs. Youmans DC et
al. American Journal of Radiology 1998;171:1415-1419.
(3) Kleinman PK. Diagnostic imaging of child abuse. 1998. Mosby p
238, 422-423.
Table 1: Skeletal survey in NAI (3):
A
single film (‘baby gram’) should be avoided as it gives an
unsatisfactory exposure and combined views of chest abdomen pelvis
and limbs should also be avoided. Limb detail is poor, with
oblique projections of most joints.
Skull (SXR)
AP and lateral, plus Towne's view for occipital injury.
SXRs should be taken with a skeletal survey even if a CT scan has
been performed.
Body:
AP/frontal chest (including clavicles)
Oblique views of the ribs (left and right)
AP Abdomen with pelvis and hips
Spine:
Lateral spine - cervical and thoraco-lumbar
Limbs:
AP humeri, AP forearms
AP femurs, AP Tib/fib
PA hands and AP feet
Supplemented by:
- Lateral views of any suspected shaft fracture.
- Lateral coned views of the elbows/wrists/knees/ankles may
demonstrate metaphyseal injuries in greater detail than AP views
of the limbs alone. The consultant radiologist should decide this,
at the time of checking the films with the radiographers.
Brain imaging:
CT (brain and bone windows) is the method of choice in the acute
phase.
A linear skull fracture may not be identified on CT (on bone
windows) - see SXR above.
Interval MRI may give greater detail of subdural haematomas and
parenchymal injury. There is a body of opinion among paediatric
neuroradiologists in the UK that a CT brain scan should be
included routinely with the skeletal survey in suspected NAI for
all pre-mobile young children. It is recommended that a CT brain
scan is considered for all small children in whom NAI is suspected
- if CT is then judged not worthwhile or indicated in that
individual case, it is advisable that this be documented in the
notes.
