The complete diagnostic autopsy has changed little since its inception. It involves invasive surgery to examine the three body cavities – head, thorax and abdomen – and works on the assumption that it will provide enough information to identify a cause of death on a balance of probabilities.

But that examination omits many parts of the body, meaning it’s possible to miss significant information – especially if the person conducting the autopsy lacks training, experience, or sufficient time for a thorough investigation. That’s where post-mortem cross-sectional imaging – computed tomography (CT) in adults and magnetic resonance imaging (MRI) in children – enters the picture.

Post-mortem computed tomography (PMCT) alone can identify 60–70 percent of natural causes of death; that alone isn’t sufficient, so the technique is most commonly used as an adjunct to invasive autopsy. Why does PMCT fail to provide an answer in so many cases? The principal reason is that you can’t confidently diagnose coronary artery disease – a leading cause of natural death – with PMCT alone. To see that, you have to add in angiography (PMCTA), which increases the diagnostic success rate to about 92 percent of all natural causes of death, as well as 100 percent of non-suspicious trauma cases (1). So if you want to know absolutely everything about a particular case, you do both – but if you need a more volume-based system, you can save time and resources by starting with PMCTA, triaging out those cases that need to be autopsied.