RADIOLOGICAL FINDINGS.html
Radiological findings at a South African forensic pathology laboratory in cases of sudden unexpected death in infants
T S Douglas, PhD
N Fenton-Muir, BTech
K Kewana, MB ChB
Y Ngema, MB ChB
MRC/UCT Medical Imaging Research Unit, Department of Human Biology, University of Cape Town
L Liebenberg, MB ChB, DIP For Med (SA), MMedPath(Foren)
Division of Forensic Medicine and Toxicology, University of Cape Town
Corresponding author: T Douglas (tania@ieee.org)
Abstract
Objectives.
The work serves as a preliminary evaluation of the utility of full-body
radiography in examining cases of sudden unexpected death in infants
(SUDI).
Setting.
This paper reviews findings from full-body digital radiography in cases
of SUDI in 2008 at the Salt River Forensic Pathology Laboratory in Cape
Town.
Subjects. One hundred and ninety-two cases of SUDI referred to the mortuary and undergoing full-body digital radiography were reviewed.
Design.
Imaging reports were cross-referenced with death registry data. Manner
of death, cause of death, whether an autopsy had taken place, and
radiological findings, were recorded and analysed.
Results.
The absence of bone fractures was recorded as an imaging finding in 40%
of cases. The most common type of imaging pathology was lung disease.
In cases where autopsies were performed and pathology was found on
imaging, the findings of the two methods of examination were consistent.
Conclusions.
Imaging might have served to assist cause-of-death determination based
on case history, and therefore full-body radiography could improve the
workflow in busy forensic pathology laboratories. More detailed and
consistent recording of imaging findings is required before stronger
conclusions may be drawn regarding the utility of full-body digital
imaging of paediatric cases in forensic pathology laboratories.
Introduction
Radiographs have been used in forensic examinations since the discovery of X-rays,1
and have contributed to forensic autopsy by providing a permanent, but
incomplete, record of the anatomy and pathology of the deceased prior
to autopsy, particularly documenting fractures and the localisation of
foreign material such as bullet fragments.2 The significance of radiographic soft-tissue findings in forensic pathology has been the subject of only a few studies.3
Full-body digital radiography has been shown to be useful for the rapid detection of unsuspected fractures4 and multiple injuries5
in a trauma unit; the same benefits would apply to forensic pathology
investigation. Forensic radiography is currently not a regular feature
of the management of sudden unexpected death in infants (SUDI) in South
Africa. A retrospective audit of 512 cases comparing the investigation
of SUDI at two large medico-legal mortuaries in South Africa found that
no radiological investigations were done as part of the post mortem
examination.6 The absence of additional investigations such as radiology was attributed to probable financial and resource constraints.
A full-body low-dose digital X-ray system has,
however, been used in medico-legal autopsies in South Africa for a
number of reasons.7 It
allows rapid localisation of foreign bodies with the aid of multiple
views, which has benefits where fast burial is dictated by religious
practice and in criminal investigation. It is easily operated by
trained staff. Its low radiation dose does not pose a major risk to
staff.
This paper reviews the findings from full-body
radiography in SUDI, with reference to autopsy results and causes of
death, over a one-year period at the Salt River Forensic Pathology
Laboratory in Cape Town. The incidence of SUDI and the circumstances
surrounding it have received little research attention in South Africa.
No nationally accepted protocol exists for the investigation of SUDI;
and in instances where an infant had an underlying medical
condition/disease, the opinion of the treating clinician often
determines whether or not a sudden/unexplained infant death is referred
to a medico-legal facility.6 This paper serves as a preliminary evaluation of the utility of full-body radiography in examining cases of SUDI.
Methods
A Lodox Statscan full-body digital radiography system8
was installed at the Salt River Forensic Pathology Laboratory in 2007.
Cases that had undergone imaging between 1 January and 31 December 2008
were cross-referenced with data from the death registry at the Division
of Forensic Medicine and Toxicology at the University of Cape Town. The
following were recorded: manner of death – of interest in this
study was SUDI; age – only cases two years or younger were
included; cause of death (CoD); whether an autopsy had taken place; and
the radiological findings. Data had been entered by 4 consultant
pathologists, 6 registrars and a medical officer. Not all cases seen at
the laboratory undergo imaging; the pathologist determines whether or
not imaging is required. No protocol exists for the recording of
radiological findings.
The study was approved by the Human Research Ethics Committee of the Faculty of Health Sciences of the University of Cape Town.
Results
An antero-posterior (AP) radiograph was taken in
all cases, while additional views were taken in some cases. No
information was recorded on the reason for imaging. A total of 1 033
recorded cases were imaged in 2008, among them 197 cases of SUDI. Two
of the SUDI cases had no associated notes or death registry
information, and the files for 3 cases were unavailable because of
criminal investigation; these were excluded. Therefore 192 cases were
included in the study.
CoD, determined with or without autopsy, is shown
in Fig. 1. The majority of pathology involved the lungs. The imaging
notes referred to bone fractures in 77 (40%) cases; no bone fractures
were recorded.
Autopsies were performed on 121 SUDI cases. For the
71 cases that were not autopsied, the reported death was due to natural
causes (in some cases the natural CoD was specified, and in others not
– cf. Fig. 1). In cases where pathology was found on imaging, the
notes did not indicate whether or not the imaging findings contributed
to CoD determination. However, a larger percentage of autopsied cases
showed no pathology on imaging, while a larger percentage of
non-autopsied cases showed pathology on imaging (Fig. 2), which
suggests that imaging might have assisted in the determination of
natural causes based on case history, without autopsy. Twenty-two
autopsied cases for which CoD was specified had corresponding imaging
findings; a comparison of imaging and autopsy findings is shown in
Table 1. Imaging findings for cases without autopsy are shown in Table
2. Fig. 3 shows an example of a full-body image of one of the cases.
The findings revealed right upper lobe opacification of the lung. Fig.
4 shows a chest image extracted from a full-body scan; lung disease is
evident and the findings were reported as bilateral pulmonary
infiltrates.
Discussion
The absence of bone fractures was frequently
recorded as an imaging finding. Skeletal surveys by X-ray imaging are
part of the SUDI protocol in some centres to rule out the possibility
of non-accidental injury or to detect rib fractures associated with
resuscitation.9 Such surveys
typically require several images to cover the entire skeleton.
Full-body imaging facilitates a complete skeletal survey from one
orientation in one image, regardless of subject size, as the imaging
field of view on the Lodox Statscan is adjustable from 100 mm x 100 mm
to 1800 x 680 mm. While additional views may be required, the full-body
AP image replaces a number of smaller AP views, and therefore would
reduce the time taken for a skeletal survey.
For the majority of SUDI cases, the CoD was lung
disease. The majority of imaging pathology findings reflected lung
disease. This is consistent with the results of other studies3 and with the limitations of radiographs in showing soft tissue pathology.
In cases where
autopsies were performed and pathology was found on imaging, the
findings of the two methods of examination were consistent. In
contrast, De Lange et al.3
found poor agreement between autopsy and radiological findings owing to
the presence of post mortem artefacts, which could not readily be
differentiated from true pathology and were more likely to occur with
long time intervals between death and imaging. Our study did not show
radiological findings that were unaccounted for on autopsy, and did not
record the time interval between death and imaging. Future work should
include a prospective comparison of autopsy and radiological findings,
with recording of time intervals between the two types of study, to
ascertain the extent and time dependence of post mortem artefacts.
Although individual case reports contained no
indication of the extent to which imaging contributed to CoD
determination, findings on imaging without autopsy in cases of death
owing to natural causes suggest that imaging might have served to
assist CoD determination based on case history.
Full-body radiography may improve the workflow in a
busy forensic pathology laboratory, such as the one in Salt River,
which receives more than 3 500 cases annually and has to maintain a
large daily turnover to prevent overflow, given limited storage
capacity,10 However, more
detailed and consistent recoding of imaging findings is required before
stronger conclusions may be drawn regarding the utility of full-body
digital imaging in cases of SUDI.
Acknowledgements.
Funding was provided by Lodox Systems and the Technology and Human
Resources for Industry Programme (THRIP) of the National Research
Foundation in South Africa.
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Fig. 1. Cause of death in 192 infant cases designated as SUDI on entering the forensics laboratory.
Fig.
2. Imaging findings for autopsied and non-autopsied cases; autopsies
were performed on 121 cases; 71 cases were not autopsied.
Fig. 3. Full body image with opacification in the right upper lobe of the lung.
Fig. 4. Cropped chest image with bilateral pulmonary infiltrates.
Table 1. Comparison of imaging findings and autopsy results for 22 cases for which pathology was found on imaging
No. of cases
Imaging findings
Cause of death (CoD)
7
Opacification in lung fields
Pneumonia/lung pathology/aspiration
7
Consolidated lung fields
Lower respiratory tract infection/bronchopneumonia/sepsis
2
Air bronchograms
Pneumonia
2
Obscured heart margins
Congenital cardiac disease
1
Bilateral pleural effusions
Pneumonia
1
Hyperinflation of lungs
Bronchiolitis
1
Lymphadenopathy
Disseminated tuberculosis
1
Infiltrates
Pneumonia
Table 2. Imaging findings for 32 non-autopsied cases where pathology was found on imaging
No. of cases
Imaging findings
Lung disease
14
Opacification
4
Pneumonia/bronchopneumonia
4
Pulmonary pathology
2
Infiltrates
2
Air bronchograms
1
Lower respiratory tract infection
1
Pleural effusion
Other
4
Distended bowel
1
Enlarged liver