Images of Death; the Virtual Autopsy

When a person dies in suspicious circumstances, a forensic pathologist will be called on to perform an autopsy on the deceased.  The purpose of the forensic autopsy is to determine:

• the cause of death e.g. blunt force trauma, gunshot, etc., 
 
• the mechanism of death i.e. what was actually used to bring about death e.g. baseball bat, gun etc.,
 
• the manner of death e.g. homicide.

 

The forensic autopsy may also provide valuable evidence on the size, shape and features of the murder weapon, as well as give an indication of the time of death.  However, a  forensic autopsy cannot discover why the victim died. 

 

Police officers may rely heavily on the autopsy findings in the early days of a criminal enquiry to determine the direction of their investigations.

 

However, sometimes, the body may be so decomposed that the pathologist cannot give any sort of opinion as to the cause of death.  Furthermore, the act of cutting into a badly decomposed body can create further damage, leaving the pathologist with even less to examine.

 

Fortunately, there is now an alternative method of obtaining evidence from decomposed and badly damaged bodies, which is gradually being adopted around the world.  It is also used on 'fresh' bodies. 

 

The Virtual Autopsy or 'Virtopsy' is the brainchild of Michael Thali and his team from the University of Bern, Switzerland.  The initial research project arose from a need to solve a high-profile homicide.  A possible murder weapon had to be compared with the impression in the skull of the victim with a view to identifying the weapon with a high level of certainty.  The Virtopsy developed from this research.  

Essentially, the Virtopsy uses modern, cross-sectional imaging techniques to supplement and partially replace traditional autopsy.  The results of the Virtopsy are presented as a permanent 3-D digital record.  You may be familiar with two of the processes used in the Virtopsy process from hospital visits, namely CT and MRI.

 

Computed Tomography or CT is an imaging method that uses X-rays to create pictures of cross-sections of the body.  A computer creates separate images of the body, which are called 'slices'.  In a Virtopsy, CT scans can be used to detect air embolisms and the effects of decomposition, for example.

 

The magnetic resonance imaging (MRI) technique uses magnetic and radio waves to create high quality images of tissues and organs within the body.  It is used to detect soft tissue injury and organ trauma, for example.

 

In addition, angiography may be used to address any circulatory questions.  Here,.a liquid dye is injected into the body to make the blood vessels easy to visualise.

A robotic system called a 'Virtobot' can be used in conjunction with the CT scanner to sample tissues from the body as well as documenting (recording details of) the surface of the body at high resolution.

To see how all this fits together, here is a Virtopsy video showing the 'workflow' of the process.  Here you will see all the equipment demonstrated, mainly on a dummy.

 

 

 

 

 I've also found this useful chart that lists the processes involved.

There are many advantages of a Virtopsy over a traditional forensic autopsy.  Here are a few:
 

• The technique is non-destructive.
 
• A permanent and easily retrievable digital record is available to allow consultation with other colleagues or when a second autopsy by another pathologist is requested by the opposing legal team. 
 
• A permanent 3-D image of the findings of the Virtopsy allows every pathologist to examine the same material, no matter how far advanced the investigation.
 
• The body is effectively preserved in digital form, so there is no need for an exhumation if new evdence comes to light in the future.  Also, no evidence has been lost if the body has been cremated.
 
• Trauma that would be impossible to see in a traditional autopsy may be detected by a Virtopsy.
 
• 2-D and 3-D post-processing of the Virtopsy images helps the pathologist to visualise the findings for presenting evidence in court.
 
• It is easy to examine bodies that are contaminated by infection, toxic substances or biohazards.
 
• The Virtopsy overcomes any religious or moral objections to autopsy. 

Here is a video showing the Virtopsy in casework in France.

 

 

 

Could the Virtopsy ever be a replacement for the traditional forensic autopsy?  At the moment, I suspect the answer is no.  It's primary use is as a tool to be used in cases where dissection is not feasible, such as a badly decomposed body, or where the forensic evidence is particularly hard to visualise, such as matching a weapon to an impression on the body.

 

I hope you found this blog post useful.  I welcome your comments. Please let me know if there is anything particular you would like me to write about.  I'll be glad to oblige.