Postmortem radiology is useful but no substitute for necropsy

Editor—Recent high profile events surrounding postmortem examination procedures have required that additional means of examination be sought.¹ A necropsy describes a variety of methods used to ascertain the cause of death or pathological conditions within a deceased person, and ranges from a needle biopsy to radiology. Common usage of the term, however, refers to the thorough macroscopic and microscopic examinations of the organ systems, which are evidence based and derived from the centuries of research into pathological processes and their correlation with premorbid conditions. Information from the necropsy aids examiners to complete a medical certificate of cause of death to the best of their knowledge and belief, as instructed by law.²

Postmortem radiology is a useful tool to confirm the presence of diseases, but it should not be used to replace the gold standard examination, a necropsy.³ Bisset et al in their paper often do not confirm their diagnoses through this gold standard; diagnoses where they are used show a difference of importance placed by the pathologist as to the cause of death. It should also be noted that most diagnoses provided by imaging are in fact “modes of death” and as such, if left unqualified by an underlying causation, are unacceptable on a death certificate.⁴ This error may result in referral of the case by the registrar general to the coroner for further investigation, which may cause further upset for the next of kin.²

The difficulty in interpretation of images obtained by magnetic resonance scanning is well recognised in pathology, with anecdotal evidence of diagnostic inaccuracies discovered when examining subsequent surgical specimens or at necropsy. Postmortem artefacts, recognisable to the pathologist, also remain to be thoroughly documented radiologically.

The political problems also require addressing should it become apparent that cadavers are undergoing imaging when waiting lists continue to increase. Even though the work is performed out of hours, or in private facilities, it may result in embarrassment for local health authorities.

The necropsy in itself is comparatively inexpensive and may provide accurate information based on histology, microbiology, and toxicology—tests that are beyond the reach of magnetic resonance imaging. Histological and microbiological results are essential for the creation of health statistics that form the basis of future healthcare provision. Would postmortem radiology alone allow identification of the type of tumour or the infectious causation? As such, surely doctors are failing to identify the cause of death “to the best of their knowledge and belief.”⁴