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Recent Advances in Forensic Pathology: Post-mortem CT imaging
Criminal Bar Association of NZ Saturday 5 August, 2017 Recent Advances in Forensic Pathology: Post-mortem CT imaging DR JOANNA GLENGARRY, FORENSIC PATHOLOGIST Victorian Institute of Forensic Medicine Melbourne, Australia
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Post-mortem CT imaging
Fluoroscopy CT scans X-rays Ultrasound MRI Using radiology to image the deceased
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So why is Post-mortem CT Imaging important?
The autopsy has been thought of as a low-tech tool in death investigation… But forensic pathology is joining the 21st century Emergence of the use of post-mortem CT scans (PMCT) in forensic pathology cases. Routine use in suspicious cases and homicides Changing how we investigate death It will change how we present evidence Now part of the NZ Coroner’s Act1 UK Chief Coroner has issued guidelines on its use2 Coroner’s Amendment Act 2016 S21A
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So is this just a new fad? PMCT has emerged from experimental and novel to established and validated tool in the forensic pathology toolbox: its utility and place in the process is no longer in question
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Question: What group was responsible for the development of the clinical CT machine?
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According to some3 the development of the CT scanner was a result of the Beatles’ success.
The Beatles’ success enabled EMI to fund one of their engineers, Sir Godfrey Hounsfield’s research which ended with developing the first CT scanner. While on an outing in the country, Hounsfield came up with the idea that one could determine what was inside a box by taking X-rays at all angles around the object. He then constructed a computer that could take data from such X-rays to create an image of the object in "slices". In 1979 he was awarded the 1979 Nobel prize in Medicine with Allan Cormack4 3. Dr B Timmis - Beatles greatest gift... is to science 4. "The Nobel Prize in Physiology or Medicine 1979". Nobelprize.org. Nobel Media AB Web. 3 Jul 2017.
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What is CT? CT – Computed tomography
CAT – Computed Axial Tomography, Computer Aided Tomography From the Greek tomos (slice) and graphein (to write). Computer-processed combinations of many X-ray measurements taken from different angles to produce cross-sectional (tomographic) images (virtual "slices") of specific areas of a scanned object, allowing the user to see inside the object without cutting.
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CT Scanner Auckland Mortuary
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Forensic Pathology_Glengarry
25 June 2015 CIB Induction_RNZPC
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Forensic Pathology_Glengarry
25 June 2015 CIB Induction_RNZPC
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Forensic Pathology_Glengarry
25 June 2015 CIB Induction_RNZPC
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Why do we do it? Why must we do it?
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Why must we do it? Medical history:
Prerequisite for death investigation and autopsy In forensic pathology casework, the history is often incomplete, inaccurate or of poor relevancy The PMCT can provide important ancillary information prior to autopsy, mitigating a lack of history
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Why must we do it? Planning the autopsy:
Provisional location of disease and trauma allows the pathologist to plan the physical approach or special dissection Hazard detection Needles, knife tip, medical equipment Unexploded ordnance Foreign bodies/projectiles
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Finding bullets
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Finding bullets
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Why must we do it? Finding disease and trauma:
Obscure sites of skeletal injuries Roof of mouth Pelvis Spine Limbs Complex injury depiction Abnormal air / gas Air embolism Pneumothorax, pneumoperitoneum Occult skull base fracture Diagnosing disease
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Obscure sites of trauma
Roof of the mouth
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Complex Injuries
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When the family object? Haemopericardium – cause?
Family do not want an autopsy Angiography shows aortic dissection No requirement for autopsy
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Why must we do it? Documentation / Legal transparency:
Document both the presence of and absence of findings Full 3D volumetric record: Complete surface record Clothing, medical devices, property, items in hair Skin breaches Condition of body before autopsy Permanent record of internal injury, disease Retrospective review of wound tracks Quality review, medical corroboration Once the body is cremated, it’s a tad challenging to go back…
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Permanent digital record
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Wound track
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Wound track
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Why must we do it? Identification:
Visual, dental, fingerprints and DNA identification are not able to be used in every case Medical information to assist ID Age estimation Evidence of prior surgery, fractures Medical devices, prostheses or implants Disaster Victim Identification5 Triage of cases Identify comingling and non-human remains Sex and age Guide pathologist to sources of ID 5. O’Donnell et al. Contribution of postmortem multidetector CT scanning to identification of the deceased in a mass disaster: experience gained from the 2009 Victorian bushfire disaster. For Sci Int 2011; 205: 15-28
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Why must we do it? Disaster Victim Identification:
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Why must we do it? Presenting evidence:
To students or trainees To peers To the Court
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Case Study 1 - Homicide 23M found at his residence with multiple injuries
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Case Study 1 - Homicide
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Case Study 1 - Homicide
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Case Study 1 - Homicide A great many injuries in keeping with both mattock and knife as weapons of infliction Problematic come Court time: Cannot show external photos due to extreme facial injuries Still need to demonstrate injuries and patterns to jury CT 3D renders were used in lieu of external photos
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Case Study 2 – Homicide
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Case Study 2 – Homicide
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Disadvantages Pathologists are not radiologists…yet Cost
Learning curve Shades of grey Optical mileage Cost Massive data storage requirements Need to retrain technicians Not all disease states are shown
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Radiology doesn’t show everything
Soft tissue injuries poorly revealed Fine/small injuries Causes of death not revealed Histological diagnoses Metabolic or biochemical processes Toxicology Fires
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What does the literature say?
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Does it work for Natural Disease?
Roberts (UK) et al6 examined discrepancies between PMCT diagnosis and autopsy diagnosis in cases of natural disease Discrepancy between PMCT when a radiologic COD was evident: 16% Comparable to the 15% error rate cited for Death Certificates Problem: The most common causes of death seen in FP practise are not seen with PMCT 6. Roberts ISD et al. Post-mortem imaging as an alternative to autopsy in the diagnosis of adult deaths: a validation study. Lancet 2012; 379:
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What about trauma? Scholing (Netherlands) et al7 evaluated PMCT for determining COD and identification of specific injuries in trauma cases: Agreement on COD between PMCT and the autopsy was % In some cases, PMCT detected more injuries than autopsy In some cases the PMCT missed injuries seen at autopsy My experience? With appropriate case selection and experience in using PMCT, many trauma cases can be examined by PMCT plus a careful external examination without critical loss of information 7. Scholing M et al. The value of postmortem computed tomography as an alternative to autopsy in trauma victims: a systematic review. European Radiology 2009; 19:
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Children? Sieswerda-Hoogendororn (Netherlands) et al8 evaluated PMCT for determining COD in children: PMCT identified the same COD as autopsy in 67% of unnatural deaths But 0% agreement between CT and autopsy in natural disease My experience? Imaging is an essential adjunct to autopsy, particularly to exclude non-accidental injury. But you need an autopsy to diagnose natural disease in children. 8. Sieswerda-Hoogendoorn T et al. Postmortem CT compared to autopsy in children; concordance in a forensic setting. International Journal of Legal Medicine 2014; 128:
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Oh yeah? Show me how this actually works…
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The NZ capability Ability to perform the scan depends on an authority to do so from the Coroner Auckland has in-house CT scanner Scan all suspicious deaths, homicides Scan trauma deaths, decomposed cases, shooting, hanging, diving deaths Natural disease cases at pathologist discretion Other forensic centres in Palmerston North, Wellington, Christchurch depend on goodwill of hospital clinical CT scanner Logistical issues regarding timing, body transport, cultural acceptability Initially the adult scans viewed and interpreted by forensic pathologist, later a report is provided by a radiologist is requested Auckland has dedicated radiologists with an interest in PMCT Paediatric autopsies have immediate report provided by paediatric radiologist
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Case Study 3 - Suicide 56F witnessed standing on the side of the road
Truck passing felt a “bump” as its trailer rolled over an object The female found deceased on road behind trailer Medical records show history of depression Police visit to her house revealed a suicide note
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Case Study 3 - Suicide
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Case Study 3 - Suicide
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Case Study 3 - Suicide Circumstances and scene suggestive of suicide
Police report no suspicious features External examination and CT scan showed severe injuries incompatible with life Pattern of injuries consistent with a rollover mechanism No evidence of a standing pedestrian impact on CT or external examination No injuries inconsistent with the scenario as currently known Dilemma: What will a full autopsy examination add to this case? Detection of natural disease Full documentation of injuries Coroner’s Decision: No autopsy Cause and manner of death can be determined from above information
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Case Study 4 – Trauma vs Natural
82M found unconscious at home – collapse or fall? Conveyed to hospital but deteriorated in the emergency department before investigations could be performed Palliated at family’s request and died later that day Medical history includes heart disease with previous bypass grafting, previous stroke, high blood pressure Hospital doctors unable to write death certificate as COD unknown and possibly due to fall Family opposed to autopsy
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Case Study 4 – Trauma vs Natural
Issues arising before CT: Unclear if death due to a fall with head trauma Unclear if death due to underlying disease with a collapse Has more than sufficient a burden of natural disease to account for sudden death Was there a treatable cause that the hospital should have diagnosed? Family do not want an invasive investigation Coroner needs to determine cause and manner of death
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Case Study 4 – Trauma vs Natural
Blood in the brain
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Case Study 4 – Trauma vs Natural
Does the CT help resolve the issues? Intracerebral haemorrhage Unfiltered diagnostic possibilities: trauma, tumour, hypertensive bleed, vascular malformation, amyloid angiopathy, warfarin therapy The appearances in a man of this age are classic for a condition known as amyloid angiopathy – an age related degenerative change in the blood vessels of the brain predisposing to rupture and catastrophic bleeding No evidence of trauma collapse rather than fall A fatal process diagnosed A cause of death available Manner of death is natural Not an easily treatable disease, poor prognosis No requirement for full autopsy family's wishes respected without compromise of information
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How will PMCT affect you?
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Evidential Issues? Are there evidential issues with performing PMCT prior to autopsy in homicides? No Protocols have been developed to account for this Body bag remains sealed at all times from scene to mortuary to CT to theatre OC Body accompanies the body from scene, into CT room, to theatre Body bag is not opened and body is not manipulated in performing the CT Body movement is limited to lifting on and off CT table
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Presenting the Evidence
Forensic pathologists are well aware that their evidence is difficult for some to hear We are exquisitely aware of how confronting autopsy photos may be, even the “nice” ones We are trying to find better ways to educate the jury, without alienating them or losing the accuracy of information Computer 3D modelling programmes available but aren’t perfect and are generic, not specific PMCT 3D images may be the way to get accuracy, sanitisation and understandable evidence all in one
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Computer model Injury indicative only Not specific to the deceased PMCT 3D image Actual injuries Specific to the deceased
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Computer model Injuries indicative only Not specific to the deceased PMCT 3D image Actual injuries Specific to the deceased
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Whose evidence is it? PMCT is very much a collaborative effort in practise Forensic Pathologists Experts at diagnosing disease and injury Anatomical and pathological knowledge See a greater severity of injury, a greater extreme of natural disease Understand post-mortem change and decomposition and the artefacts this generates Clinical Radiologists Experts at CT interpretation and disease diagnosis But what they see in live patients may differ to that seen in the deceased Forensic radiologists Understand the imaging of the deceased far better than clinical radiologists and are an extraordinarily valuable resource But…
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Whose evidence is it? If you want images to act as a pictorial representation of the injuries in lieu of photos, to supplement a verbal explanation or as an illustration: A forensic pathologist can do this, just like we would talk to diagrams or photos If the radiology interpretation and images require specialist interpretation and discussion of radiology-related issues: A forensic radiologist or clinical radiologist with forensic expertise will be needed Do not expect a clinical radiologist without post-mortem experience to be an expert in PMCT There are artefacts in PMCT that can mimic significant disease processes but are a post-mortem phenomenon, not “real” disease or injury9 9
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What do the Courts think?
The literature is scant in this regard Premise of the Jeffrey paper10: It is not always clear at the start of a coronial autopsy whether what appears to be a natural death, may turn out to be a covert homicide or whether future criminal or civil court proceedings may occur Would the use of PMCT alone affect any potential judicial proceedings? Survey of Judge, Barrister, Solicitor, Coroner and Police “Non-invasive autopsy report” 10
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Findings of note: Issues:
CT was excellent for demonstrating trauma and COD was same in the majority of cases and differences were only minor Manner of death unchanged in all cases But it’s not just about cause and manner of death! The judge was the one most accepting of the non-invasive reports Issues: PMCT as a viable alternative? Autopsy is Gold Standard so anything less has reduced credibility Loss of ability to perform histology No internal neck dissection in neck compression Concern regarding false positive or negative findings Uncertainty or speculation in evidence is unhelpful A less than full examination means there is uncertainty and pathologist may not be able to exclude possibilities There may be uncertainty after a full PM, but at least one may be “certainly uncertain” with a full dataset of information Accepted that non-invasive PM has financial benefits and is more acceptable to families It was felt the use of CT imagery would enhance the presentation of findings in Court
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The future? What will tomorrow be like?
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Will I be out of a job? Thankfully not!
Forensic pathologists continue to drive this revolution and are becoming skilled forensic radiologists The Royal College of Pathologists of Australasia is forming a Forensic Radiology Special Interest Group Potential for a Diploma in Forensic Radiology
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PMCT and Evidence The VIFM, led by Dr Soren Blau (anthropologist) and Dr Chris O’Donnell (forensic radiologist) Pilot study examining use of 3D printing of PMCT images as evidence in Court 3D print of a skull fracture vs verbal evidence vs photo vs image of CT 3D image has excellent level of clarity as perceived by jurors and with good levels of acceptability
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In Practise PMCT continues to revolutionise how medicolegal death investigation will occur But for the Courts, I think that full autopsies will remain the Gold Standard for some time yet Angiography will play an increasing role What level of proof will you require for me to tell you an injury exists? The more we do, the more we will know our limits Whatever happens, it’s a fun ride ahead!
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