Jasmin Amoroso

Post-mortem computed tomography ventilation; simulating breath holding

Whilst the literature continues to report on advances in the use of post-mortem computed tomography (PMCT), particularly in relation to post-mortem angiography, there are few papers published that address the diagnostic problems related to post-mortem changes in the lungs and ventilation. We present a development of previous methods to achieve ventilated PMCT (VPMCT). We successfully introduced a supraglottic airway in 17/18 cases without causing overt damage, despite rigor mortis. Using a clinical portable ventilator, we delivered continuous positive airway pressure to mimic clinical breath-hold inspiratory scans. This caused significant lung expansion and a reduction in lung density and visible normal post-mortem changes. All thoracic pathology identified at autopsy, including pneumonia, was diagnosed on VPMCT in this small series. This technique provides a rapid form of VPMCT, which can be used in both permanent and temporary mortuaries, allowing for the post-mortem radiological comparison of pre-ventilation and post-ventilation images mimicking expiratory and inspiratory phases. We believe that it will enhance the diagnostic ability of PMCT in relation to lung pathology.

Pump injector system applied to targeted post-mortem coronary artery angiography

Targeted post-mortem computed tomography angiography (PMCTA) is one of several methods described that can be used to investigate the coronary arteries after death. Previously, this particular method has involved the manual injection of contrast media. However, manual systems do not mimic physiological conditions (arterial pressure) and may not provide optimal contrast, as iodinated contrast medium dissipates rapidly from the intra- to the extra-vascular space. To try and overcome these problems, we now report the use of a clinical automatic pump injector for targeted PMCTA. We present our final protocol for this pump system developed from experience of 74 cases, showing how these clinical pumps can be translated from clinical into autopsy practice for the injection of air and positive contrast media to visualise the coronary arteries of cadavers.

Diagnostic accuracy of post-mortem CT with targeted coronary angiography versus autopsy for coroner-requested post-mortem investigations: a prospective, masked, comparison study

Summary Background England and Wales have one of the highest frequencies of autopsy in the world. Implementation of post-mortem CT (PMCT), enhanced with targeted coronary angiography (PMCTA), in adults to avoid invasive autopsy would have cultural, religious, and potential economic benefits. We aimed to assess the diagnostic accuracy of PMCTA as a first-line technique in post-mortem investigations. Methods In this single-centre (Leicester, UK), prospective, controlled study, we selected cases of natural and non-suspicious unnatural death referred to Her Majestys (HM) Coroners. We excluded cases younger than 18 years, known to have had a transmittable disease, or who weighed more than 125 kg. Each case was assessed by PMCTA, followed by autopsy. Pathologists were masked to the PMCTA findings, unless a potential risk was shown. The primary endpoint was the accuracy of the cause of death diagnosis from PMCTA against a gold standard of autopsy findings, modified by PMCTA findings only if additional substantially incontrovertible findings were identified. Findings Between Jan 20, 2010, and Sept 13, 2012, we selected 241 cases, for which PMCTA was successful in 204 (85%). Seven cases were excluded from the analysis because of procedural unmasking or no autopsy data, as were 24 cases with a clear diagnosis of traumatic death before investigation; 210 cases were included. In 40 (19%) cases, predictable toxicology or histology testing accessible by PMCT informed the result. PMCTA provided a cause of death in 193 (92%) cases. A major discrepancy with the gold standard was noted in 12 (6%) cases identified by PMCTA, and in nine (5%) cases identified by autopsy (because of specific findings on PMCTA). The frequency of autopsy and PMCTA discrepancies were not significantly different (p=0·65 for major discrepancies and p=0·21 for minor discrepancies). Cause of death given by PMCTA did not overlook clinically significant trauma, occupational lung disease, or reportable disease, and did not significantly affect the overall population data for cause of death (p≥0·31). PMCTA was better at identifying trauma and haemorrhage (p=0·008), whereas autopsy was better at identifying pulmonary thromboembolism (p=0·004). Interpretation For most sudden natural adult deaths investigated by HM Coroners, PMCTA could be used to avoid invasive autopsy. The gold standard of post-mortem investigations should include both PMCT and invasive autopsy. Funding National Institute for Health Research.

Consent of the recently bereaved to post-mortem targeted angiography research: 207 adult cases

Aims To present our experience of prospective telephone consenting for post-mortem CT angiography (PMCT-A) research using HM coroners’ cases. Methods Local ethics committee, research and development office, and local HM coroners gave their permission for the families of the deceased, in cases where a ‘routine’ coroners autopsy had been authorised, to be approached for their consent to PMCT-A research before the autopsy examination. A forensic pathologist or trial consenter telephoned the next of kin, discussed the nature of the study and obtained verbal informed consent for post-mortem imaging, angiography, case-dependent histological and toxicology sampling and for the use of the images for teaching and training. Thematic analyses of the reasons for giving or refusing consent are provided. Results Of the 207 cases approached, seven relatives refused to enter their next of kin into the study (96.6% consent rate). Conclusions This study shows that prospective consenting for HM coroners’ cases to be used for autopsy research is feasible in adults, and can be done ethically, and in the limited time available, by obtaining the consent of the next of kin by telephone before autopsy.

The effect on cadaver blood DNA identification by the use of targeted and whole body post-mortem computed tomography angiography

Post-mortem computed tomography angiography (PMCTA) involves the injection of contrast agents. This could have both a dilution effect on biological fluid samples and could affect subsequent post-contrast analytical laboratory processes. We undertook a small sample study of 10 targeted and 10 whole body PMCTA cases to consider whether or not these two methods of PMCTA could affect post-PMCTA cadaver blood based DNA identification. We used standard methodology to examine DNA from blood samples obtained before and after the PMCTA procedure. We illustrate that neither of these PMCTA methods had an effect on the alleles called following short tandem repeat based DNA profiling, and therefore the ability to undertake post-PMCTA blood based DNA identification.

Post-mortem computed tomography coaxial cutting needle biopsy to facilitate the detection of bacterioplankton using PCR probes as a diagnostic indicator for drowning

We report for the first time the use of coaxial cutting needle biopsy, guided by post-mortem computed tomography (PMCT), to sample internal body tissues for bacterioplankton PCR analysis to investigate drowning. This technical report describes the biopsy technique, the comparison of the needle biopsy and the invasive autopsy sampling results, as well as the PMCT and autopsy findings. By using this new biopsy sampling approach for bacterioplankton PCR, we have developed on previous papers describing the minimally invasive PMCT approach for the diagnosis of drowning. When such a system is used, the operator must take all precautions to avoid contamination of the core biopsy samples due to the sensitivity of PCR-based analytic systems.

Could Post-mortem Computed Tomography Angiography Inform Cardiopulmonary Resuscitation Research?

AIM Firstly, to develop an optimised chest compression post mortem computed tomography angiography protocol in the adult human during closed chest compression to investigate cardiopulmonary resuscitation blood flow, and secondly to provide preliminary observations of post-mortem anatomical cardiac chamber movement using a novel radiolucent static chest compression device. METHODS Variable volumes of radiological contrast agent were injected intravenously into a series of consented human cadavers. Each cadaver had chest compressions delivered with a LUCAS™2 mechanical chest compressor. Following each cycle of chest compressions, each cadaver was imaged with a Toshiba Aquilion CXL 128 slice computed tomography (CT) scanner to investigate the extent of contrast distribution. A chest compression simulator was then designed and built to allow static CT imaging of 1cm incremental cadaver chest compressions to a depth of 5cm. RESULTS Mechanical compressions: Ten cases were recruited for the CT angiography component of the study. Two were subsequently excluded from the study at the time of the initial, non-contrast PMCT scan. A further case was recruited in Emergency Department (ED). CT demonstrable antegrade arterial contrast distribution was achieved in 2 cases. The other 7 cases, including that undertaken in ED shortly after death, showed venous retrograde flow. Incremental compressions: Five new cases underwent incremental chest compression imaging. All cases demonstrated compression of the sternum, ribs, atria and great vessels. The right and left ventricles were not compressed, but moved laterally and inferiorly, further into the left chest cavity. The left hemi-diaphragm, stomach and liver moved inferiorly. The sternum, ventricles, hemi-diaphragm, stomach and liver all moved back to their original position on incremental release. CONCLUSION The study suggests that with further protocol modification and access to human cadavers as near to death as possible, chest compression post mortem computed angiography (CCPMCTA) could be used as a model for the study of human vascular flow and heart movement during CPR.