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MINI-SYMPOSIUM: NON-INVASIVE RADIOLOGICAL AUTOPSY
An image of sudden death:utility of routine post-mortemcomputed tomographyscanning in medico-legalautopsy practiceChris O’Donnell
a Unlike England and Wales but similar to many areas of the world, all
AbstractPost-mortem computed tomography (CT) is an established technique at
Victorian Institute of Forensic Medicine (VIFM) used to assist pathologists
in determining cause and manner of death. It also plays an important role
in identification of deceased individuals as exemplified by the 2009
“Black Saturday” Victorian bushfires in which the remains of 164 individ-
uals were subjected to disaster victim identification procedures. CT scan-
ning is now explicitly incorporated into the Victorian Coronial legislation
(Coroners Act 2008), and is an important component of the preliminary
examination process whereby a pathologist reviews the circumstances
of a death, any pre-existing medical history, whole body CT images, the
external appearances of the body and expedited (overnight) toxicological
screen results, so that a recommendation to the Coroner may be formu-
lated regarding the likely cause of death and necessity for autopsy. This
process has seen a reduction in autopsies from a mean of 62% over
the last 5 years to 47% of admissions in less than 12 months. VIFM
pathologists perform the primary interpretation of CT images in consulta-
tion with a radiologist. A process of quality audit has been instituted in
order to detect systematic errors in this interpretation, in addition to
a structured education programme directed to correct those errors. New
imaging techniques, notably whole body CT angiography and dual energy
CT have the prospect of even more substantial forensic application.
Keywords angiography; cause of death; computed tomography;
coroner; post-mortem
Introduction
In mid 2005, a computed tomography (CT) scanner was installed
into the mortuary of the Victorian Institute of Forensic Medicine
(VIFM). Since that time all deceased persons admitted to the
Institute have been CT scanned from head to toe, and images
permanently stored on a picture archiving and communication
system (PACS). Well over 15,000 cases have now been exam-
ined. CT images do not replace autopsy but assist pathologists in
determining cause of death, manner of death, mechanism of
injury and documentation of injury for presentation as evidence
in court.1 CT is also useful in identification of the deceased where
Chris O’Donnell MBBS FRANZCR MMed GradDipForMed is the Principal
Consultant Radiologist at the Victorian Institute of Forensic Medicine
and Department of Forensic Medicine, Monash University, Australia.
DIAGNOSTIC HISTOPATHOLOGY 16:12 552
other techniques are not available or difficult to attain.2 In a mass
disaster scenario, CT is used as a triage tool.3 In the 2009 “Black
Saturday” Victorian bushfires, radiologists used CT imaging to
separate human from non-human remains, determine the
number of individuals within a body bag, assist odontologists
and anthropologists in assigning gender and age, detect disease
processes or medical procedures, and at the time of autopsy,
localize metallic items within the body for retrieval by the
pathologist. Routine CT scanning prior to autopsy or other bodily
interventions produces images that are available at any time for
retrospective review by pathologists or other interested parties,
for example following the discovery of additional information by
police in a process known as “digital exhumation”.
Post-mortem CT interpretation is not the same as clinical CT.
Images that would normally be considered unacceptable to the
clinical radiologist are routine in post-mortem scanning. Notable
contributory factors include a lack of oral or intravenous radio-
graphic contrast, malpositioning of the body in the gantry, and
metallic artefact due to foreign bodies located in or on the
deceased person. Image analysis requires an understanding of
the changes to visceral anatomy that routinely occur after death,
features of the agonal process, artefacts of death including
autolysis and putrefaction, as well as the consequences of
resuscitation including external cardiac massage. Failure to
recognize or understand these features can lead the reader of CT
images into errors of analysis with the potential for inaccurate
evidence or conflict with the pathologist’s autopsy findings.
Radiological findings of visceral pathology on post-mortem CT
are similar but invariably more extreme than CT performed in the
clinical environment given that individuals have succumbed to
that pathological process.
The interpreter of post-mortem CT must have a thorough
understanding of forensic autopsya practice in particular the
nature of injury and outcome of trauma, realizing that
the mechanism or manner of death may be as important to the
forensic pathologist as the consequences of inflicted injury on
a particular organ. Ultimately the individual who produces
a written radiological report must understand the relevant
legislation, be prepared to provide verbal expert evidence to
a court and endure the demands of a legal system that rightly
tests the validity and interpretation of presented facts in
a rigorous manner. Substantial background information
including (but not restricted to) the circumstances surrounding
the death should be available at the time of image analysis.
Ideally CT imaging should be undertaken in a co-operative
environment with pathologists and radiologists working together
in a forensic institute or situation where the CT scanner is co-
located with pathologists such as in a hospital department. It is
not the province of an occasional user working in isolation.
This issue of CT image interpretation has recently been
explored by Filograna.4 She has discussed the three sources of
medico-legal deaths including so-called routine coroner’s cases, are
examined in a single Institute by forensic pathologists. Thus where the
word forensic is used within the text it is taken to include all deaths, both
routine and forensic i.e. it includes deaths that would be examined by
histopathologists in England and Wales.
� 2010 Elsevier Ltd. All rights reserved.
MINI-SYMPOSIUM: NON-INVASIVE RADIOLOGICAL AUTOPSY
error in diagnostic imaging; notably perceptual (finding present
but not recognized), cognitive (incorrect interpretation of
a finding) and system factors (organizational issues in the
institution) and related them to the conduct of post-mortem CT
imaging. The relative novelty of post-mortem CT imaging
means that all three factors are commonly encountered.
Perceptual errors are inevitable when the observer is inexperi-
enced with the imaging modality or there is a new application of
that modality i.e. CT imaging of the deceased. Cognitive error is
also likely if the paradigm of clinical CT interpretation is applied
directly to the evaluation of the deceased and system error will
flourish if the imaging is being performed and interpreted in an
environment that is divorced from the forensic pathological
context.
Post-mortem CT images should therefore be assessed by those
with a background in forensic medicine and understanding of
post-mortem pathology and cross-sectional imaging. This has
spawned a new subspeciality termed “necro-radiology”.5 At VIFM
the sheer number of admissions and limited access to radiolog-
ical expertise precludes the written interpretation of all CT scans
by a radiologist (as routinely occurs in clinical practice).
Pathologists have taken primary responsibility for the viewing of
images with a radiologist providing consultation on a case by
case basis. This pragmatic approach has been criticized yet
forensic pathologists have many of the desirable attributes
described above i.e. an in-depth understanding of traumatic
effects on the body and experience in provision of expert
evidence as well as court practices. Pathologists are well aware of
the artefacts of death and the mistakes of interpretation that can
occur in forensic practice, described so eloquently in the classic
paper by Moritz.6 Pathologists at the VIFM have been educated
on the CT findings of such artefacts as well as the radiological
correlates of pathological processes e their particular area of
expertise. Unlike the radiologist who is often constrained by
limited provision of background information, the pathologist has
considerable data available at the time of CT reporting notably
circumstances surrounding death provided by police, previous
medical history, toxicology and ultimately the ability to perform
external examination of the deceased person even if no autopsy
is forthcoming. Any CT findings identified on the pre-autopsy CT
scan can if necessary be viewed directly at the time of autopsy.
This process of ‘validation’ has been invaluable and an ongoing
educative exercise to pathologists.
Although initially reluctant, pathologists have embraced the
new technology notwithstanding the potential for interpretive
error due to lack of experience7 or understanding of CT image
acquisition. An ongoing teaching programme has been supple-
mented by a quality audit whereby 10% of all cases are retro-
spectively reviewed by the radiologist. Radiologist’s findings are
matched with the pathologist’s written CT observations and any
discrepancies graded as substantial (i.e. a CT finding that might
reasonably be expected on radiological grounds alone to be the
cause of death), minor (i.e. a CT finding that of its own might not
reasonably be expected to be the cause of or responsible for the
death, but might possibly be considered to be a contributory
factor to the death) or incidental (i.e. a CT finding that is inci-
dental to the cause of death but is of particular medical or
pathological interest). Substantial and minor discrepancies are
discussed with the pathologist and in appropriate cases, images
DIAGNOSTIC HISTOPATHOLOGY 16:12 553
reviewed at a weekly departmental pathology meeting. This
process allows for the identification of systematic error and
redress by education.
The audit has secondary consequences. It reveals technical
issues i.e. CT hardware failure or findings considered by the
radiologist to be the result of error by technical staff. Any such
finding is relayed to the mortuary management and corrections
made. If systematic technical error is revealed then re-education
of technologists is instituted. The process also acts as an ongoing
learning process for the reviewing radiologist since CT results are
directly correlated with the pathologist’s autopsy findings and
interpretations.
In the 4 years following installation, CT was used very much as
an adjunct to the routine procedures of forensic pathology at VIFM.
For example if CT revealed an obvious cause of death e.g. ruptured
atheromatous, abdominal aortic aneurysm, and the circumstances
were not deemed suspicious, then a recommendation might be
made to the coroner that autopsy was not required as a ‘natural’
disease process responsible for the death had been identified. If the
cause of death was not obvious on circumstantial grounds but
there was a significant history of medical co-morbities, non-
suspicious circumstances, and no specific CT findings (including
no evidence of significant trauma) then autopsy might not be
performed if an objection to such a procedure had been raised by
the senior next of kin and the coroner was of the view that death
was most probably the result of natural causes (otherwise not
specified). Alternatively the circumstances of deathmight not have
been suspicious yet CT revealed a concerning finding such as
a subdural haematoma or unexplained healing rib fractures in
a child prompting further investigations including a full autopsy.
CT was routinely used by pathologists following autopsy to clarify
an autopsy finding e.g. demonstration of a pelvic fracture to
explain detected pelvic haematoma or provide an image for
presentation to investigators e.g. multiple, rounded, depressed
skull vault fractures due to injury inflicted with a hammer. On
occasion pathologists might overlook the examination or docu-
mentation of a particular body region at the time of autopsy yet
retrospectively be able to review CT images prior to completion of
their report e.g. diameter of the aortic valve.
All previous applications of post-mortem CT have continued,
however, recent changes to the Victorian Coroners Act8 have
reinforced the use of CT in everyday practice. The Act creates the
concept of a preliminary examination entailing (a) visual
including dental examination of the body (b) review of personal
and health information, (c) taking of bodily fluids, (d) imaging of
the body including X-rays, CT, MRI, US and/or photography, (e)
taking of surface swabs and (f) fingerprinting of the body. A
preliminary examination (or component part thereof) is per-
formed on all deceased persons reported to the coroner and
admitted to VIFM. The Act allows the coroner to determine that
a reportable death requires no further investigation “if a medical
investigator conducts a medical examination on the deceased
person and provides a report to the coroner that includes an
opinion that the death was due to natural causes”. At VIFM a so-
called duty pathologist is the nominated medical investigator
created in response to the Act. Using the facility of the prelimi-
nary examination, the duty pathologist forms a judgement on
whether the death was natural and provides to the coroner
a recommendation as to the necessity for an autopsy. The
� 2010 Elsevier Ltd. All rights reserved.
Figure 2 Coronal MPR view of the heart through the root of the aorta
showing a large volume haemopericardium towards the apex of the lateral
ventricle with a crescent of hyperdense blood in the wall of the ascending
aorta (arrow). Findings are indicative of ruptured Type A dissection of the
ascending aorta.
MINI-SYMPOSIUM: NON-INVASIVE RADIOLOGICAL AUTOPSY
coroner then makes a determination on whether autopsy should
progress, usually in consultation with the deceased’s senior next
of kin.
The duty pathologist reviews all aspects of the preliminary
examination including CT images prior to formulation of an
opinion on whether a death is natural and/or recommendation to
the Coroner for autopsy. On that basis CT analysis is now
formalized and integral to the conduct of forensic pathology
services at VIFM; albeit the issues addressed at the time of
preliminary CT assessment are not necessarily complete or well-
defined. For example details on the depth and direction of
a penetrating metallic object or the number and location of
fractures are less important than their presence, prompting the
pathologist to brief the coroner on the need for an autopsy. The
specific CT findings can later be analyzed to assist the pathologist
in performing that formal autopsy or subsequently at the time of
constructing the autopsy report in consultation with an expert
radiologist. In contrast the detection of subarachnoid haemor-
rhage and a basilar aneurysm (Figure 1) by the duty pathologist
provides a likely cause of natural death that may obviate the
need for further coronial investigation by way of an autopsy.
The Act also allows the coroner to “impose conditions on the
manner in which an autopsy is to be performed”8 such as
limiting the number of body cavities to be explored or the organs
removed. CT scanning can be useful in this regard specifically if
the duty pathologist finds an abnormality in a particular
anatomical region but is unable to determine the cause of that
abnormality e.g. a cerebral mass lesion but no other abnormality,
or spontaneous haemopericardium but no cause evident. The
two likely causes of such a condition are ruptured thoracic aortic
dissection (Figure 2) or myocardial infarct. The exact determi-
nation of which pathology is responsible could have profound
consequences for the family of the deceased, especially if the
deceased is young, as thoracic dissection may be associated with
Figure 1 Midline sagittal MPR view of the brain in a deceased individual
who collapsed and died suddenly. Extensive subarachnoid and intra-
ventricular blood is associated with a large, hyperdense ovoid mass
(arrow) in the pre-pontine cistern compressing the medulla and pons
posteriorly. Appearances are due to a large basilar artery aneurysm that
has spontaneously ruptured into the subarachnoid space.
DIAGNOSTIC HISTOPATHOLOGY 16:12 554
familial genetic conditions including Marfan syndrome. Limited
autopsy prompted by the CT scan findings (including the exclu-
sion of significant pathology elsewhere) may be more acceptable
to next of kin when they are considering the possibility of
autopsy, especially if the value of such a procedure (particularly
in accurately determining the cause of death) is explained to the
family members.
Subsequent to the adoption of a duty pathologist at VIFM in
mid 2009, analysis of autopsy rates has shown a substantial
reduction to 47% of admissions from a mean of 62% over the
previous 5 years. These autopsy rates had been stable since
2004/05 despite the installation of the CT scanner in mid 2005
(Figure 3). Although CT is not necessarily entirely responsible for
this decline, the formalized process of preliminary examination
has encouraged pathologists to use CT images as part of their
formulation and advice to the coroner.
The future of post-mortem CT imaging is assured. Newer
techniques of whole body, minimally invasive CT angiography9
promise an even greater contribution to forensic practice and
technical advances such as dual energy CT, the prospect of
quantitative analysis as well as improved detection of pathology
including subcutaneous haematoma.10 Magnetic Resonance
Imaging (MRI) with its improved delineation of soft tissues will
also make a substantial contribution despite the cost of instal-
lation and technical difficulties in the mortuary environment.11
Summary
In summary CT scanning at VIFM has three main roles: (a) a tool
for triage by the duty pathologist to determine if autopsy should be
recommended to the Coroner (in conjunction with review of
circumstances, medical history, toxicology and external exami-
nation), (b) an adjunct to autopsy by predicting findings for the
pathologist, clarification of observations and better understanding
of trauma mechanisms and (c) assistance in identification of the
� 2010 Elsevier Ltd. All rights reserved.
Admisions to VIFM
Years
Pe
rce
nta
ge
100
80
60
2001/02
2002/03
2003/04
CT installed Duty path.
Non-autopsy
Autopsy
2004/05
2005/06
2006/07
2007/08
2008/09
2009/10
40
0
20
Figure 3 Graph demonstrating the ratio of autopsy to non-autopsy cases
admitted to the VIFM since 2001/02. CT scanner was installed into the
mortuary in mid 2005 yet the ratio of autopsy to non-autopsy cases
changed very little until the introduction of the duty pathologist at the
end of 2009. Note a drop in the autopsy rate in 2009/10 to 47% from an
average of 62% in the preceding 4 years.
MINI-SYMPOSIUM: NON-INVASIVE RADIOLOGICAL AUTOPSY
deceased. In the future more sophisticated applications of CT
including whole body angiography and dual energy CT as well as
MRI will enhance these roles assisting pathologists in better
understanding of the cause and mechanism of death. A
DIAGNOSTIC HISTOPATHOLOGY 16:12 555
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� 2010 Elsevier Ltd. All rights reserved.