Systematic analysis of the radiologic findings of aortic dissections on unenhanced postmortem computed tomography

Challenges to Acute Aortic Dissection in a Regional Hospital

Acute aortic dissection is often a life-threatening disorder; in particular, type A aortic dissection necessitates urgent surgical intervention. Therefore, in regions where there are no cardiovascular surgeons, its treatment is quite challenging. Our facility, the Nasu Red Cross Hospital, located in the northern part of Tochigi Prefecture, is a core hospital for advanced emergency medical care, with eight cardiologists who can provide emergency coronary angioplasty for patients with acute coronary syndrome. However, we have no cardiovascular surgery section, so it is challenging to treat patients who require urgent surgical intervention. Therefore, we promptly transfer patients with type A aortic dissection to 8 facilities inside and outside the prefecture that have cardiovascular surgery sections. In regional hospitals like ours, without cardiovascular surgeons, it is necessary to provide a qualified diagnosis, initiate treatment for patients with acute aortic dissection including immediate blood pressure lowering and pain control using narcotics, and transfer patients eligible for urgent surgical intervention promptly to facilities with cardiovascular surgery sections. For smooth patient transfer, it is essential to build a close medical cooperation system that has daily interactions.

Postmortem contrast-enhanced computed tomography via direct large-vessel puncture

The aim of this study was to assess the usefulness of postmortem contrast-enhanced CT (PMeCT) performed via direct large-vessel puncture when routine postmortem CT suggests a vascular lesion as the cause of death. PMeCT was performed in 9 cases (4 male, 5 female) with a mean age of 76 years (range 52-92) at the time of death. The mean time elapsed since death was 29.1 h (12.0-72.0). The location of the target vessel for puncture was determined based on the CT table position and a grid placed on the body surface. An 18-G spinal needle was advanced to the puncture site, and the needle tip was confirmed to have reached the intended blood vessel. Using negative pressure with a 20-ml syringe, the needle tip was advanced until reverse bleeding was confirmed. Diluted contrast medium was injected slowly to ensure its dispersion within the blood vessels. Following confirmation of no extravasation, additional doses of diluted contrast agent were injected in 3-4 divided doses, with CT scans obtained at each step to track the distribution of contrast agent over time. PMeCT was successful in all cases, revealing cardiac tamponade in 7 (ascending aortic dissection, n = 6; cardiac rupture, n = 1), thoracic aortic aneurysm rupture, n = 1, and iliac artery aneurysm rupture, n = 1. There were no cases of procedure-related extravasation (pseudo-lesions). When postmortem CT reveals pericardial hematoma or bleeding in the thoracic or abdominal cavity, PMeCT can identify the source of bleeding.

Incidence and characteristics of acute aortic dissection in patients with out-of-hospital cardiopulmonary arrest evaluated by non-contrast computed tomography

Background

The exact epidemiology of acute aortic dissection, including cases of out-of-hospital cardiopulmonary arrest, is unclear. We aimed to investigate the incidence and characteristics of acute aortic dissection in patients with out-of-hospital cardiopulmonary arrest transferred to our institution and validate the related factors to out-of-hospital cardiopulmonary arrest in Stanford type A acute aortic dissection.

Methods

We retrospectively reviewed the acute-phase computed tomography data of patients with out-of-hospital cardiopulmonary arrest who visited our hospital between 1 January 2015 and 31 December 2017.

Results

Among 1011 consecutive patients with out-of-hospital cardiopulmonary arrest, excluding those aged 17 years and younger and exogenous out-of-hospital cardiopulmonary arrest, such as suicide and trauma, 934 underwent computed tomography examination and 71 (7.6%) were diagnosed with acute aortic dissection: 66 with Stanford type A and five with type B acute aortic dissection (out-of-hospital cardiopulmonary arrest group). Seventy-five patients without out-of-hospital cardiopulmonary arrest with Stanford type A acute aortic dissection visited our institution during the same period (non-out-of-hospital cardiopulmonary arrest group). Age, incidence of massive bloody pericardial effusion and massive intrathoracic haemorrhage were significantly higher in the out-of-hospital cardiopulmonary arrest than in the non-out-of-hospital cardiopulmonary arrest group (78 ± 8 years, 72.7% and 24.2% vs. 70 ± 13 years, 26.7% and 1.3%, respectively; all P < 0.01). These variables were independently related to out-of-hospital cardiopulmonary arrest.

Conclusions

There may be more patients with acute aortic dissection with out-of-hospital cardiopulmonary arrest than previously thought. Aortic rupture into the pericardial space or thoracic cavity is the major cause of out-of-hospital cardiopulmonary arrest in these cases. Non-contrast computed tomography can be used to diagnose acute aortic dissection in patients with out-of-hospital cardiopulmonary arrest. Our study is one of a few to evaluate the real circumstances surrounding acute aortic dissection and its epidemiology.

Non-contrast computed tomography of type A acute aortic dissection in patients with out-of-hospital cardiopulmonary arrest: a case series

Background

The prognosis of patients admitted for acute aortic dissection (AAD) has remarkably improved. However, we must also consider out-of-hospital cardiopulmonary arrest (OHCPA) patients while assessing the prognosis. In recent years, autopsy imaging has become more common as an alternative to conventional autopsy. Therefore, we reviewed our OHCPA patients with type A AAD using acute phase non-contrast computed tomography (CT).

Case summary

Here, we report a case series of three patients who developed OHCPA and were diagnosed with type A AAD using non-contrast CT. Although the direct causes of death varied in each case, we could easily determine the direct causes of death from clinical course of the condition and from non-contrast CT.

Discussion

Although non-contrast CT does not completely replace autopsy, if its convenience and non-invasiveness make it possible for more patients to undergo the procedure, the real prognosis (including morbidity and mortality) may be better understood. Therefore, we considered it significant to use non-contrast CT for investigating the cause of sudden death.

Evidence of aortic dissection and Marfan syndrome in a mummy from the Capuchin Catacombs of Palermo, Sicily

The authors report on the assessment of an anthropogenic mummy of a young man from the Capuchin Catacombs of Palermo, Sicily, tentatively dated from the mid- to late 19^th century AD. The mummy was investigated by full-body CT examination. CT images clearly showed aortic dissection classified as Stanford-A. Due to the relation of aortic dissection to inherited connective tissue diseases in young people, such as Marfan syndrome, conspicuous and pathological findings possibly indicating the presence of underlying Marfan syndrome were assessed. Several systemic features were scored that supported the presence of underlying Marfan syndrome in this mummy. These findings were: pectus carinatum and chest asymmetry, dural ectasia, protrusio acetabuli, dolichocephaly, down-slanting palpebral fissures, malar hypoplasia and (probable) reduced elbow extension. Aortic dissection, a cardinal feature of Marfan syndrome, turned out to be the diagnostic key for the paleoradiological diagnosis of this disease. The demonstrated CT findings contribute to the spectrum of cardiovascular diseases and inherited connective tissue disease in the fields of paleopathology and paleoradiology.

Accuracy of non-contrast PMCT for determining cause of death

The aim of this study was (1) to compare levels of accuracy regarding the categorization of causes of death between non-contrast post-mortem computed tomography (PMCT) and the final forensic report as well as between autopsy and the final forensic report, and (2) to assess levels of confidence regarding the categorization of causes of death after non-contrast PMCT and after autopsy. This prospective study was conducted over a 5 month period during which 221 cases were admitted to our institute for forensic investigations. Whole-body PMCT and forensic autopsy were performed in every case. Of these, 101 cases were included in the final study population. Inclusion criteria were: (1) age > 18 years, (2) presence of at least one of the two principal investigators at the time of admission. One radiologist and one forensic pathologist independently read all PMCT datasets using a report template. Cause of death category and confidence levels were determined by consensus. Forensic autopsy was performed by two forensic pathologists; both unblinded to imaging results. Both post-imaging and post-autopsy cause of death categorization were compared against the final cause of death, as stated in the forensic expert report, which included findings from histology and/or toxicology. Accuracy of post-imaging cause of death categorization in reference to the final cause of death category was substantial (82%, 83/101 cases, Kappa 0.752). Accuracy of post-autopsy cause of death categorization in reference to the final cause of death category was near perfect (89%, 90/101 cases, Kappa 0.852). Post-imaging sensitivity and specificity regarding the categorization of causes of death were 82% and 97%, respectively. Post-autopsy sensitivity and specificity regarding the categorization of causes of death were 89% and 98%, respectively. There was a high consistency between the accuracy of post-imaging cause of death categorization and post-imaging levels of confidence. There was less consistency between accuracy of post-autopsy cause of death categorization and post-autopsy levels of confidence. In this study categorization of causes of death based on non-contrast enhanced PMCT alone, and on PMCT and macroscopic autopsy together, proved to be consistent with the final cause of death-category as determined based on all available information including PMCT, autopsy, and (if available) histology and/or toxicology in more than 82% and 89% of all cases, respectively. There was higher consistency between levels of confidence and accuracy of causes of death categorization was higher post-imaging than post-autopsy. These results underline the fact that the diagnostic potential of PMCT goes beyond the assessment of trauma cases.

Differentiation of hemopericardium due to ruptured myocardial infarction or aortic dissection on unenhanced postmortem computed tomography

The aim of the study was to evaluate unenhanced postmortem computed tomography (PMCT) in cases of non-traumatic hemopericardium by establishing the sensitivity, specificity and accuracy of diagnostic criteria for the differentiation between aortic dissection and myocardial wall rupture due to infarction. Twenty six cases were identified as suitable for evaluation, of which ruptured aortic dissection could be identified as the underlying cause of hemopericardium in 50% of the cases, and myocardial wall rupture also in 50% of the cases. All cases underwent a PMCT and 24 of the cases also underwent one or more additional examinations: a subsequent autopsy, or a postmortem magnetic resonance (PMMR), or a PMCT angiography (PMCTA), or combinations of the above. Two radiologists evaluated the PMCT images and classified each case as "aortic dissection", "myocardial wall rupture" or "undetermined". Quantification of the pericardial blood was carried out using segmentation techniques. 17 of 26 cases were correctly identified, either as aortic dissections or myocardial ruptures, by both readers. 7 of 13 myocardial wall ruptures were identified by both readers, whereas both readers identified correctly 10 of 13 aortic dissection cases. Taking into account the responses of both readers, specificity was 100% for both causes of hemopericardium and sensitivity as well as accuracy was higher for aortic dissections than myocardial wall ruptures (72.7% and 87.5% vs 53.8% and 75% respectively). Pericardial blood volumes were constantly higher in the aortic dissection group, but a statistical significance of these differences could not be proven, since the small count of cases did not allow for statistical tests. This study showed that diagnostic criteria for the differentiation between ruptured aortic dissection and myocardial wall rupture due to infarction are highly specific and accurate.