Open Access Research BMJ Open: first published as 10.1136/bmjopen-2017-018834 on 16 March 2018. Downloaded from Can virtual autopsy with postmortem CT improve clinical diagnosis of cause of death? A retrospective observational cohort study in a Dutch tertiary referral centre Lianne J P Sonnemans,1 Bela Kubat,2,3 Mathias Prokop,1 Willemijn M Klein1,4 To cite: Sonnemans LJP, ABSTRACT Strengths and limitations of this study Kubat B, Prokop M, et al. Objective To investigate whether virtual autopsy with Can virtual autopsy with postmortem CT (PMCT) improves clinical diagnosis of the ► This study investigated the diagnostic performance postmortem CT improve clinical immediate cause of death. diagnosis of cause of death? for clinical cause of death determination by use of Design Retrospective observational cohort study. Inclusion A retrospective observational postmortem CT and takes into account the added criteria: inhospital and out-of-hospital deaths over the age of cohort study in a Dutch tertiary value over clinical diagnosis alone. 1 year in whom virtual autopsy with PMCT and conventional referral centre. BMJ Open ► The immediate cause of death (ie, direct cause of autopsy were performed. Exclusion criteria: forensic cases, 2018;8:e018834. doi:10.1136/ death) was the main outcome rather than the prima- bmjopen-2017-018834 postmortal organ donors and cases with incomplete scanning ry cause of death (ie, underlying cause of death or procedures. Cadavers were examined by virtual autopsy with Prepublication history for basic illness) as from a clinical point of view, diagno- ► PMCT prior to conventional autopsy. The clinically determined this paper is available online. sis and treatment of the immediate cause of death cause of death was recorded before virtual autopsy and was then To view these files, please visit is the most urgent. adjusted with the findings of virtual autopsy. Using conventional the journal online (http:// dx. doi. ► The sensitivity for clinical cause of death determi- org/ 10. 1136/ bmjopen- 2017- autopsy as reference standard, we investigated the increase in nation, with and without postmortem CT, is investi- 018834). sensitivity for immediate cause of death, type of pathology and gated on multiple levels of precision; the immediate anatomical system involved before and after virtual autopsy. cause of death as well as the involved type of pa- Received 24 July 2017 Setting Tertiary referral centre. Revised 20 January 2018 thology and anatomical location were investigated. Participants 86 cadavers that underwent conventional http://bmjopen.bmj.com/ Accepted 23 January 2018 ► The retrospective design in a tertiary care centre and virtual autopsy between July 2012 and June 2016. has probably introduced a selection bias towards Intervention PMCT consisted of brain, cervical spine and patients with diagnostic difficulties or unresolved chest–abdomen–pelvis imaging. Conventional autopsy issues, resulting in an underestimation of the diag- consisted of thoracoabdominal examination with/without brain nostic performance compared with more general autopsy. causes of death. Primary and secondary outcome measures Increase ► An unexpected low consent rate for postmortem CT in sensitivity for the immediate cause of death, type of in cases with consent for conventional autopsy re- pathology (infection, haemorrhage, perfusion disorder, sulted in a reduction of the statistical power of this on October 2, 2021 by guest. Protected copyright. other or not assigned) and anatomical system (pulmonary, study. cardiovascular, gastrointestinal, other or not assigned) involved, before and after virtual autopsy. 1 Department of Radiology and Results Using PMCT, the sensitivity for immediate cause of Nuclear Medicine, Radboudumc, death increased with 12% (95% CI 2% to 22%) from 53% healthcare. It is therefore remarkable that in Nijmegen, The Netherlands 2Department of Pathology, (41% to 64%) to 64% (53% to 75%), with 18% (9% to 27%) a time of heightened interest in improving Netherlands Forensic Institute, from 65% (54% to 76%) to 83% (73% to 91%) for type of patient safety, healthcare quality and error Hague, The Netherlands pathology and with 19% (9% to 30%) from 65% (54% to prevention, worldwide autopsy rates continue 3Department of Pathology, 76%) to 85% (75% to 92%) for anatomical system. to decline from roughly 40% in the 1960s Maastricht UMC+, Maastricht, Conclusion While unenhanced PMCT is an insufficient to below 10% nowadays.1–7 Religious and The Netherlands substitute for conventional autopsy, it can improve 4 emotional objections to the invasiveness of Department of Radiology and diagnosis of cause of death over clinical diagnosis alone conventional autopsies, both by the relatives Nuclear Medicine, Maastricht and should therefore be considered whenever autopsy is UMC+, Maastricht, The not performed. and the doctors, are considered as some of Netherlands the reasons given for this decline. At present, determination of the cause of death relies Correspondence to INTRODUCTIOn Lianne J P Sonnemans; heavily on clinical assessment. Despite an Lianne. Sonnemans@ Autopsies are traditionally regarded as the increase in the use and improvement of diag- radboudumc. nl ‘gold standard’ in quality monitoring of nostic techniques in the last decades, major Sonnemans LJP, et al. BMJ Open 2018;8:e018834. doi:10.1136/bmjopen-2017-018834 1 Open Access BMJ Open: first published as 10.1136/bmjopen-2017-018834 on 16 March 2018. Downloaded from error rates of approximately 25% have not substantially PMCT images, as postmortem imaging is a relatively decreased.8–10 According to the Goldman classification new field of expertise. Conventional autopsy consisted system, major errors are defined as clinically missed diag- of thoracic-abdominal autopsy with or without examina- noses related to the cause of death. In half of these cases, tion of the brain, and included full macroscopic and this might have led to a change in therapy and prolonged microscopic inspection. Radiologists and pathologists survival, if known before death.8 were blinded to each other’s results, but had otherwise National mortality statistics are generally based on full access to electronic patient files. Radiologists and the primary cause of death (ie, underlying cause or pathologists compiled a report based on their own find- basic illness), which could be a long-standing, chronic ings and clinical findings. disease.11 However, from an individual and clinical point Data collection of view, diagnosis and treatment of the immediate cause For each cadaver, the immediate cause of death (ie, direct of death (ie, direct cause of death) is the most urgent. cause of death), type of pathology and anatomical system Accuracy rates for immediate causes of death are prob- 12 13 involved were collected in retrospect at three moments: ably lower than for underlying causes of death, due to before PMCT, after PMCT and based on conventional time constraints of the often acute situations these diag- autopsy findings. The cause of death before virtual noses present with. The high error rates emphasise the autopsy was based on clinical findings only. The cause of need to improve clinical diagnoses using techniques that death after virtual autopsy was based on both clinical find- are widely available and acceptable, for example, post- ings and PMCT. If no cause of death could be assigned mortem CT (PMCT). Previous studies have shown that as at PMCT, the cause of death was primarily based on clin- yet, PMCT is an insufficient substitute but can be used in 14 15 ical findings. Symptoms (eg, respiratory failure, sepsis, adjunct to conventional autopsy. In order to provide etc) and risk factors (atherosclerosis, hypertension) were answers and quality control also in cases without consent not considered as cause of death. Only when the primary for conventional autopsy, we investigated whether virtual source of sepsis (eg, pneumonia) was unknown, sepsis autopsy with PMCT improves clinical diagnosis of the was diagnosed as cause of death. In cases of trauma, the immediate cause of death. physical injury rather than the mechanism of trauma was assigned as cause of death. Type of pathology was scored according to the MATERIAL AND METHODS following categories: infection, haemorrhage, perfu- Study design sion disorder, other or not assigned. Perfusion disorders All cadavers of inhospital and out-of-hospital deaths comprised all cardiac and vascular perfusion disor- over the age of 1 year, who underwent both PMCT and ders not due to infection, haemorrhage or neoplasm conventional autopsy in our hospital, between July (eg, myocardial infarction, heart failure, pulmonary 2012 and June 2016, were included. Forensic cases, http://bmjopen.bmj.com/ embolism, volvulus, etc). Type A aortic dissections with postmortal donors and cases with incomplete scanning haemopericardium were grouped in the haemorrhage procedures or without full thorax-abdomen autopsy category. The type of anatomical system was scored as were excluded. Clinicians had to ask consent from rela- pulmonary, cardiovascular, gastrointestinal, other or tives for both PMCT and conventional autopsy in all not assigned. This strategy and subcategories used were cases of death. derived from the classification of anatomical regions 14 PMCT and conventional autopsy and groups of pathologies as used by Roberts et al and Wichmann et al.4 PMCT was performed as soon as possible after death on October 2, 2021 by guest. Protected copyright. and prior to autopsy.