Multiphase Postmortem Computed Tomography Angiography Research Articles

Biochemical investigations performed in pericardial fluid in forensic cases that underwent postmortem angiography

Postmortem biochemical investigations in vitreous humor samples collected before and after performing multiphase postmortem computed tomography angiography were performed in the past and demonstrated that specific contrast material injection allowed perfusion and radiological identification of the main vessels of the eye to be obtained without any changes in vitreous humor composition. In the study presented herein, we aimed to test whether the injection of the same contrast material using the same postmortem angiography protocol might influence pericardial fluid composition. Postmortem biochemical investigations were performed on pericardial fluid samples collected from bodies that underwent postmortem angiography (n = 16) prior to and post angiography. Two pericardial fluid samples were analyzed. No statistically significant differences were noticed among levels of any tested markers (urea nitrogen, creatinine, uric acid, C-reactive protein, procalcitonin, beta-hydroxybutyrate, and total IgE levels) in pericardial fluid samples collected prior to and post angiography, leading to the conclusion that pericardial fluid sampling can be delayed until after postmortem angiography when a specific contrast material injection is used.

Postmortem Imaging: An Update

Postmortem imaging is a fascinating field of forensic radiology that has seen extraordinary growth in the last 10 years. Indeed, if autopsy represents the sole reliable method of determining the definitive cause of death, imaging may provide an efficient guide to supplement conventional autopsy. This is particularly true because of several techniques that are currently available, such as postmortem computed tomography, multiphase postmortem computed tomography angiography, and postmortem magnetic resonance imaging. In this review, we explore the newer imaging techniques in forensic radiology.

Visualization of Myocardial Infarction in Postmortem Multiphase Computed Tomography Angiography: A Feasibility Study.

Recent studies have indicated that multiphase postmortem computed tomography angiography (MPMCTA) allows detection of a pathological enhancement of the myocardium in regions that correlate with the localization of the infarction at histology. The aim of this study was to verify this hypothesis by examining MPMCTA images in cases of myocardial infarction. Therefore, we investigated 10 autopsy cases where death was attributed to myocardial infarction or which showed cardiovascular pathology. As a control group, we selected 10 cases of non-natural (namely, not cardiac) death. The MPMCTA was performed in both groups to ascertain whether a pathological enhancement could be observed. We detected a myocardial enhancement in all cardiac death cases, in the same region that showed infarction at histology. No enhancement was observed in control cases. These results have important implications in the routine management of sudden cardiac death cases. In fact, MPMCTA can not only orient about the cause of death before autopsy, but can especially help to identify affected regions for guiding and improving the sampling for microscopic examination.

Towards multi-phase postmortem CT angiography in children: a study on a porcine model.

Multi-phase postmortem computed tomography angiography (MPMCTA) is a growing technique, which is standardized for adults. Application of this protocol for a children population is not so well defined. Our study aims to adapt the adult's protocol to children, using a porcine model. Three groups of 18 pigs were studied, with a weight distribution between 4 and 48kg. Different pump devices were used. Pigs of group I were studied using the Virtangio® machine, whereas pigs of groups II and III were studied using used the Medrad® machine. Study of vascular opacification was possible using a semi-quantitative method based on 26 arterial and 26 venous segments that were distributed over the entire body from the cephalic extremity to the posterior pawns. While thoracic, abdominal, and pelvic vascular opacification were complete for each individual pig in a group, group III showed better vascular opacification for the cephalic extremity. This was also true for anterior and posterior pawns vascular opacification. Spearman correlation tests showed a significant relationship between anthropometric characteristics of pigs, injection parameters, and percentage of opacified segments. A higher percentage of opacification was obtained for individuals of lower weights, with comparatively lower quantities of contrast agent injected. Postmortem computed tomography angiography (PMCTA) was possible for all the individuals, particularly for small weights (4kg) using the Medrad® machine. However, further studies are needed to better understand the procedure.

Variations in the anatomy of the vertebral artery cervical loop segment - a potential predisposing factor for traumatic basal subarachnoid hemorrhage?

Fatal traumatic basal subarachnoid hemorrhage (TBSAH) is a characteristic forensic pathological entity, the investigation of which requires special techniques. In Liverpool, post-mortem room angiography is undertaken, followed by complete removal of the vertebral arteries and histological examination. It has been observed that the arterial anatomy can be highly variable, particularly the length and course of the loop segments located between the C2 vertebra and the dura. In a number of cases of TBSAH the loop segments of torn vessels have appeared relatively short. Having observed this phenomenon subjectively in our case work, a radiological study was undertaken with the aim of quantifying vertebral artery loop anatomy variation in a 'normal' population. Multiphase post-mortem computed tomography angiography (MPMCTA) scans of 98 subjects were reviewed and the lengths of the different portions of the loop segments (foramen magnum to the upper border of C1, between C1 and C2, and the bony foramina themselves) of each vertebral artery were measured using semi-automated vessel analysis software. The measurements obtained provide objective evidence of marked anatomical variation, with some loop segments more than twice the length of others. These results are important because a short vertebral artery loop segment might be a significant factor in predisposing an individual to TBSAH following a blow to the head or neck.

Diagnosis of myocardial ischemia combining multiphase postmortem CT-angiography, histology, and postmortem biochemistry.

The aim of this study was to assess whether the identification of pathological myocardial enhancement at multiphase postmortem computed tomography angiography was correlated with increased levels of troponin T and I in postmortem serum from femoral blood as well as morphological findings of myocardial ischemia. We further aimed to investigate whether autopsy cases characterized by increased troponin T and I concentrations as well as morphological findings of myocardial ischemia were also characterized by pathological myocardial enhancement at multiphase postmortem computed tomography angiography. Two different approaches were used. In one, 40 forensic autopsy cases that had pathological enhancement of the myocardium (mean Hounsfield units ≥95) observed at postmortem angiography were retrospectively selected. In the second approach, 40 forensic autopsy cases that had a cause of death attributed to acute myocardial ischemia were retrospectively selected. The preliminary results seem to indicate that the identification of a pathological enhancement of the myocardium at postmortem angiography is associated with the presence of increased levels of cardiac troponins in postmortem serum and morphological findings of ischemia. Analogously, a pathological enhancement of the myocardium at postmortem angiography can be retrospectively found in the great majority of autopsy cases characterized by increased cardiac troponin levels in postmortem serum and morphological findings of myocardial ischemia. Multiphase postmortem computed tomography angiography is a useful tool in the postmortem setting for investigating ischemically damaged myocardium.

The usefulness of post-mortem CT angiography in injuries caused by falling from considerable heights: three fatal cases.

Post-mortem computed tomography is a diagnostic tool forming part of the arsenal available to forensic pathologists today. In addition to its usefulness in detecting bone lesions, which has long been recognized, this technique has nowadays been enhanced by the development of CT angiography. The role of multiphase post-mortem computed tomography angiography (multiphase PMCTA) is primordial, improving detection of solid organ lesions and permitting vascular lesions to be visualized directly. Our paper presents a series of three deaths by falling from a considerable height recorded since the beginning of 2012. We report the usefulness of PMCTA and the various mechanisms involved in the trauma. Most of the lesions were diagnosed by both PMCTA and autopsy, including the rare lesions, but the peripheral bone lesions and the hemopneumatocele were diagnosed only by PMCTA, while dislocation of vertebrae and the testicular fractures were detected solely by autopsy. PMCTA is a new, minimally-invasive technique which, combined with autopsy, provides better visualization and detection of certain lesions, particularly in the case of death by falling from a great height.

Pitfalls in post-mortem CT-angiography – intravascular contrast induces post-mortem pericardial effusion

We present a case where multi-phase post-mortem computed tomography angiography (PMCTA) induced a hemorrhagic pericardial effusion during the venous phase of angiography. Post-mortem non-contrast CT (PMCT) suggested the presence of a ruptured aortic dissection. This diagnosis was confirmed by PMCTA after pressure controlled arterial injection of contrast. During the second phase of multi-phase PMCTA the presence of contrast leakage from the inferior cava vein into the pericardial sac was noted. Autopsy confirmed the post-mortem nature of this vascular tear. This case teaches us an important lesson: it underlines the necessity to critically analyze PMCT and PMCTA images in order to distinguish between artifacts, true pathologies and iatrogenic findings. In cases with ambiguous findings such as the case reported here, correlation of imaging findings with autopsy is elementary.

Multiphase post-mortem computed tomography angiography in seven lethal cases of great height falls: Preliminary results of a French experience

Background The use of enhanced multislice computed tomography (MSCT) in forensic sciences has been recently developed in order to improve radiological vascular and organs injuries detection. Methods Seven suicidal cases of great height falls (4 women, and 3 men) underwent a multiphase post-mortem computed tomography angiography (MPMCTA) before medico-legal autopsy. The estimated height falls varied from 5 to 15 m. All corpses were prepared with a surgical cannulation of femoral vessels. After a non-MSCT exploration, a controlled perfusion device (Virtangio ® machine) was used with paraffin oil mixed with specific contrast agent (Angiofil ® ), allowing three time-different acquisitions (arterial, venous, dynamic). Two radiologists proceeded to images analysis. The forensic pathologist undergoing autopsies knew preliminary imaging results. Results The results of MPMCTA explorations and autopsies differed concerning detection of gas, bone fractures, and vascular ruptures (mainly cerebral), with a superiority of the MPMCTA. Autopsies were superior to MPMCTA for detection of some superficial skin lesions, which were easily accessible to external examination. Discussion Both techniques were able to diagnose some classical and typical bone, visceral and vascular lesions. Additionally, some rare injuries were found like coronary desinsertion, double thoracic aortic ruptures, inferior vena cava laceration extended to the right atrium, and pulmonary vein disruption. These findings were found with both techniques, but MPMCTA permitted better in situ lesions' illustration and documentation. Furthermore, realization of different-time acquisitions was essential for detection and comprehension of abnormal traumatic communication between cardiac cavities. Conclusion This study illustrates the complementarity of MPMCTA and autopsy in traumatic cases, and especially for cases of lethal great height falls.

Multi-phase post-mortem CT angiography: development of a standardized protocol

The objective of this work was to develop an easily applicable technique and a standardized protocol for high-quality post-mortem angiography. This protocol should (1) increase the radiological interpretation by decreasing artifacts due to the perfusion and by reaching a complete filling of the vascular system and (2) ease and standardize the execution of the examination. To this aim, 45 human corpses were investigated by post-mortem computed tomography (CT) angiography using different perfusion protocols, a modified heart-lung machine and a new contrast agent mixture, specifically developed for post-mortem investigations. The quality of the CT angiographies was evaluated radiologically by observing the filling of the vascular system and assessing the interpretability of the resulting images and by comparing radiological diagnoses to conventional autopsy conclusions. Post-mortem angiography yielded satisfactory results provided that the volumes of the injected contrast agent mixture were high enough to completely fill the vascular system. In order to avoid artifacts due to the post-mortem perfusion, a minimum of three angiographic phases and one native scan had to be performed. These findings were taken into account to develop a protocol for quality post-mortem CT angiography that minimizes the risk of radiological misinterpretation. The proposed protocol is easy applicable in a standardized way and yields high-quality radiologically interpretable visualization of the vascular system in post-mortem investigations.