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Evaluation of an acetated Ringer-based contrast material mixture for postmortem computed tomography angiography
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Diagnostic and Interventional Imaging (2020) xxx, xxx—xxx
ORIGINAL ARTICLE /Forensic medicine
Evaluation of an acetated Ringer-based contrast material mixture for postmortem computed tomography angiography A.R.J. Péporté a, D. Gascho b, S. Stamou b,c, S. Bensler d, M.J. Thali b, S. Leschka a, P.M. Flach a,b,∗ a
Clinic for Radiology and Nuclear Medicine, Cantonal Hospital Saint-Gallen, 9007 Saint-Gallen, Switzerland b Institute of Forensic Medicine, Virtopsy, University of Zurich, 8057 Zurich, Switzerland c Department of Radiology, Lake Hospital Horgen, 8810 Horgen, Switzerland d Institute for Radiology, Cantonal Hospital Baden, 5404 Baden, Switzerland
KEYWORDS Autopsy; Postmortem computed tomography angiography (PMCTA); Virtopsy; Contrast media mixture; Postmortem computed tomography (PMCT)
Abstract Purpose: The purpose of this study was to compare an established postmortem contrast medium mixture based on polyethylene glycol (PEG) to an isotonic crystalloid with acetated Ringer solution (AR) as the base, both mixed with water-soluble iodinated contrast medium for postmortem computed tomography angiography (PMCTA) with the aim to avoid alterations of the corpse during autopsy. Materials and methods: The study included 20 cadavers; 10 had PMCTA with AR and 10 with PEG. PMCTA images were analyzed with respect to image quality, vascular contrast patterns and artifacts. Autopsy was evaluated for visual, organ, vessel and haptic alterations. The Wilcoxon rank sum test was used to search for differences in image quality between the two groups. Statistical significance was set at P < 0.05. Results: AR provided excellent contrast within the right coronary artery (P < 0.001) but a lack of contrast within the left coronary artery (P = 0.008) whereas PEG showed the opposite. A better image quality was observed in the PEG group by comparison with the AR group for right common carotid artery (P = 0.03), left common carotid artery (P = 0.01) and left coronary artery (P = 0.008). No differences were found for ascending aorta (P = 0.65), aortic arch (P = 0.09), right circle of Willis (P = 0.17), left circle of Willis (P = 0.08), inferior vena cava (P = 0.07) and abdominal aorta (P = 0.08). Severe extravasation occurred in all (10/10; 100%) cadavers in the AR group but in none (0/10; 0%) in the PEG group (P < 0.001). At autopsy, visual alteration with lilac discoloration of the face was observed in 4/10 cadavers (40%) in the AR group and in 9/10 cadavers (90%) in the PEG group (P = 0.057). Haptic alterations were observed in 3/10 cadavers (30%) in the AR group and 10/10 cadavers (100%) in the PEG group (P = 0.003).
∗ Corresponding author. Clinic for radiology and nuclear medicine, Cantonal hospital Saint-Gallen, Haus 03, Rorschacher Strasse 95, 9007 Saint-Gallen, Switzerland. E-mail address: patricia.fl[email protected] (P.M. Flach).
https://doi.org/10.1016/j.diii.2020.01.009 2211-5684/© 2020 Soci´ et´ e franc ¸aise de radiologie. Published by Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: Péporté ARJ, et al. Evaluation of an acetated Ringer-based contrast material mixture for postmortem computed tomography angiography. Diagnostic and Interventional Imaging (2020), https://doi.org/10.1016/j.diii.2020.01.009
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A.R.J. Péporté et al. Conclusion: AR results in contrast medium mixture extravasation in all cadavers, but PEG altered the autopsy more severely. Both carrier substances result in specific substance-related artifacts and dependent opacification of the coronary arteries, but PEG is recommended for PMCTA exclusively with regard to diagnostic imaging. © 2020 Soci´ et´ e franc ¸aise de radiologie. Published by Elsevier Masson SAS. All rights reserved.
Postmortem computed tomography (PMCT) is currently part of the routine examination in forensic medicine [1—7]. PMCT has a potential to support forensic autopsy owing to superior detection of gas embolism and accumulations, fractures and fracture patterns, foreign bodies and even hemorrhage after large vessel ruptures or trauma [8—13]. However, the depiction of vasculature and soft tissue is limited when using unenhanced PMCT, and therefore PMCT angiography (PMCTA) was introduced to increase the accuracy of PMCT [14—23]. Although extensive research has been performed, scarce literature is available on potential artifacts and alterations of the corpses during PMCTA procedures. Bruguier et al. described technique-related artifacts and pitfalls in multiphase PMCTA using Angiofil® (Fumedica AG) [22]. These researchers reported incomplete contrast filling of the cerebral venous system, contrast agent layering in the lumen of the thoracic aorta and enhancement of the gastrointestinal mucosa [24]. However, these imaging findings were undermined by a previous publication by Grabherr et al. that reported exceedingly rare extravasation of Angiofil® when using an appropriate perfusion protocol for PMCTA [15,25]. No studies have described the alterations of the corpse that are seen during autopsy. In daily routine, unwanted alterations are often observed. They include cast-like cruor, increased organ consistency, and macroscopic changes such as patchy organ discoloration, which is especially critical for myocardial assessment, and a slippery touch under polyethylene glycol (PEG) solution-based contrast agent. In clinical emergency settings, slightly hypotonic crystalloid solutions such as acetated Ringer solution (AR) are preferably used for intravascular volume replacement therapy. The buffer ion in AR is acetate and keeps the potential of hydrogen (pH) value up, whereas in a postmortem cadaver, the pH drops significantly over time [26,27]. The purpose of this study was to evaluate an established postmortem contrast media mixture based on PEG compared to isotonic crystalloid AR solution as the base, both mixed with water-soluble iodinated contrast medium for PMCTA in order to avoid alterations of the corpse during autopsy.
Materials and methods Study cadavers The responsible justice department approved PMCT and PMCTA examination and mandated forensic autopsy. Ethical approval was obtained. A prospective analysis was
performed over a 3-year period (2014—2016). The exclusion criteria were decomposition, severe injuries and known trauma, thermal injuries, and age younger than 18 years. Based on pre-autopsy subject history, cadavers with presumed natural death were selected. The time of death was either known as documented by the minute or was estimated based on legal inspection. If estimated, the mean was used between the minimal and maximal estimated time of death. The final AR solution group included 10 cadavers. There were 6 males and 4 females, with a mean age of 57.6 ± 12.02 (standard deviation [SD)) years (median, 56 years; range: 37—76 years). Deaths were due to natural death (n = 8) as the manner of death with cardiac arrest as the cause of death, suicide (n = 1) or accidental with alcohol mixed with illicit drug intoxication (n = 1). The control group (PEG) included 10 cadavers. There were 6 males and 4 females with a mean age of 54.1 ± 9.59 (SD) years (median, 54 years; range: 34—66 years). Deaths were due to cardiac arrest (n = 8) or central regulatory failure (n = 2).
Imaging procedures PMCT technique Each subject underwent PMCT and PMCTA using a dualsource 2 × 128 section CT unit (Somatom Flash® Definition, Siemens Healthineers) with standard parameters at a 100 kVp tube voltage and 350 mAs tube current [13]. The pitch factor was 0.35, and the rotation time was 0.5 s. All reconstructions were obtained in a soft tissue window with a soft kernel and bone window with a hard kernel in an adjusted field of view [13]. A multi-modality workstation was used for image review and reporting (Syngovia® , Version VB10A, Siemens Healthineers).
Contrast media mixture The control group received an established contrast media mixture with a solution of polyethylene glycol (PEG 200, Schaerer and Schlaepfer AG) and water-soluble iodinated contrast agent (ioversol, Optiray 300® , Guerbet) at a ratio of 1:20. The experimental group received a contrast media mixture of AR solution (Fresenius Kabi AG) with the same water-soluble iodinated contrast agent as in the control group at a ratio of 1:17 (60 mL/1000 mL). Both contrast
Please cite this article in press as: Péporté ARJ, et al. Evaluation of an acetated Ringer-based contrast material mixture for postmortem computed tomography angiography. Diagnostic and Interventional Imaging (2020), https://doi.org/10.1016/j.diii.2020.01.009
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Acetated Ringer-based contrast for postmortem CTA medium mixtures had an attenuation value of 350 Hounsfield units (HU).
Angiography technique for PMCTA After unilateral inguinal skin incision, the right or left femoral artery was cannulated via a retrograde approach using a 14-Fr pediatric cannula in polyurethane (Sorin Group) and the femoral vein using an antegrade approach using a 16-Fr cannula (Sorin Group) by the autopsy technicians. The vessels were then ligated to the cannulas, which were connected to a pressure-controlled heart-lung machine (Stöckert-Shiley Computer Aided Perfusion System, Stöckert AG) at a mean flow rate of 800 mL/min by means of an 18-G needle at approximately 60 mm Hg [20]. The administered contrast medium mixture volume varied according to the deceased habitus, stature and weight and was between 1.5- and 3-L in total (mean 2.3 L, median 2.325 L). Because the venous system was prone to more volume administration than the arterial system, the arterial system was filled first, followed by the venous system administration with the arterial cannula left open. The cannulas were left in place after the angiographic procedure, removed and sutured during autopsy. The autopsy technicians drew femoral blood and, if needed, musculature at the same time whilst incising and placing the cannulas prior to PMCTA.
Radiological assessment Radiological analysis and reporting were performed by a forensic experienced board-certified radiologist and a board-certified general radiologist. Assessment was performed in consensus reading by both radiologists. The PEG control group and AR evaluation group were first assessed for image quality using a 5-category Likert-type scale on the basis of intravascular contrast and then for the presence of artifacts such as layering effects of the contrast media mixture within the vasculature and the postmortem settled blood particles, contrast media extravasation and mucosal enhancement within the respiratory, aero-digestive and gastrointestinal tract as well as musculature of the shoulder girdle, upper thorax and gluteal musculature. Physiologically postmortem occurring gas accumulation within the bowel lumen or intrahepatic was evaluated. The Likert scale categories were defined as no contrast filling (score of 1), slight filling 25% (score of 2), moderate 50% filling (score of 3), subtotal filling 75% (score of 4) and complete contrast media opacification (score of 5).
Autopsy assessment Conventional autopsy was used as the standard of reference. It included dissection of the three body cavities (skull, thorax and abdomen). After dissection, a board-certified forensic pathologist, a resident and an autopsy technician provided consensus opinion regarding visual alteration of the corpse, macroscopic organ and vessel changes and haptic alterations blinded to the contrast medium mixture used. Histology and toxicology were not consistently performed and therefore not included in this study.
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Statistical analysis Quantitative variables were expressed as means ± SD, median, first quartile (Q1) third quartiles (Q3) and ranges. Differences in quantitative variables were performed using analysis of variance and differences in qualitative variables with the Fisher exact test. The Wilcoxon rank sum test was used to search for differences in image quality between the two groups. Statistical significance was set at P < 0.05.
Results Study cadavers In the AR solution group, the mean time interval between the time of death and performance of PMCTA was 43.4 ± 29.6 (SD) hours (range: 5.3—92.2 hours; median, 38.4 hours; Q1, 17 hours; Q3, 65 hours) and the mean time interval between death and autopsy was 45 ± 31.8 (SD) hours (range: 6.3—94.3 hours; median, 41 hours; Q1, 18 hours; Q3, 74.5 hours). In the PEG group, the mean time interval between the time of death to PMCTA of 46.0 ± 24.8 (SD) hours (range: 16—92 hours; median, 50 hours; Q1, 19.1 hours; Q3, 62 hours) and the mean time interval between death and autopsy was 48 ± 26.3 (SD) hours (range: 16.4—96.3 hours; median, 52.3 hours; Q1, 19.5 hours; Q3, 63 hours). No differences in time interval between the time of death and performance of PMCTA were found between the two groups (P = 0.834). No differences in time interval between death and autopsy were found between the two groups (P = 0.821). No differences in mean age were found between the two groups (P = 0.481).
Radiological assessment Image quality Table 1 shows the results of the comparison of image quality between the two groups. A better image quality was observed in the AR group by comparison with the PEG group for right coronary artery (P < 0.001). A better image quality was observed in the PEG group by comparison with the AR group for right common carotid artery (P = 0.03), left common carotid artery (P = 0.01) and left coronary artery (P = 0.008). No differences in image quality were found for ascending aorta (P = 0.65), aortic arch (P = 0.09), right circle of Willis (P = 0.17), left circle of Willis (P = 0.08), inferior vena cava (P = 0.07) and abdominal aorta (P = 0.08). AR built a level on top of the posterior settled corpuscular particle in the large vasculature and heart chambers, whereas PEG filled the posterior settled areas and reached the ostium of the left coronary artery but not the right. In the AR group, the right coronary artery showed better degrees of opacification in all cadavers by comparison with the left coronary artery (mean, 2.6; median, 2; Q1—Q3, 1—4.5) (Fig. 1). In the PEG group, the right coronary artery showed lower degrees of opacification compared to the AR group (Fig. 2). One subject in this group died from acute cardiac arrest due to left coronary artery occlusion, thus resulting in poor opacification.
Please cite this article in press as: Péporté ARJ, et al. Evaluation of an acetated Ringer-based contrast material mixture for postmortem computed tomography angiography. Diagnostic and Interventional Imaging (2020), https://doi.org/10.1016/j.diii.2020.01.009
Asc. aorta
Aortic arch
Left CCA
Right CW
Left CW
Right CA
Left CA
IVC
Abd. Aorta
3 5 5 2 5 4 5 4 5 5 4.3 ± 1.06 5 (4—5)
3 5 5 2 4 4 5 4 5 5 4.2 ± 1.03 4.5 (4—5)
2 5 1 5 5 5 5 5 5 5 4.3 ± 1.49 5 (5—5)
2 5 5 5 5 5 5 4 3 5 4.4 ± 1.07 5 (4.25—5)
5 5 5 5 5 5 5 5 5 5 5.0 ± 0 5 (5—5)
1 5 3 5 1 1 2 1 2 5 2.6 ± 1.78 2 (1—4.5)
4 5 5 5 5 5 5 4 5 5 4.8 ± 0.42 5 (5—5)
5 3 3 4 5 5 5 5 5 5 4.5 ± 0.85 5 (4.25—5)
5 5 5 5 5 5 5 5 5 5 5.0 ± 0 5 (5—5)
5 5 5 5 5 5 5 5 5 5 5.0 ± 0 5 (5—5)
5 5 5 5 5 5 5 5 5 5 5.0 ± 0 5 (5—5)
5 5 5 5 5 5 5 5 5 5 5.0 ± 0 5 (5—5)
1 5 1 1 1 3 5 2 2 2 2.3 ± 1.57 2 (1—2.75)
5 5 5 5 5 5 2 5 5 5 4.7 ± 0.95 5 (5—5)
4 4 4 4 5 5 2 5 5 4 4.2 ± 0.92 4 (4—5)
5 5 5 5 5 5 5 5 5 5 5.0 ± 0 5 (5—5)
0.03
0.01
0.17
0.08
<0.001
0.008
0.07
0.08
A.R.J. Péporté et al.
Asc. Aorta: ascending aorta; CCA: common carotid artery; CW: circle of Willis; CA: coronary artery; IVC: inferior vena cava; Abd. Aorta: abdominal aorta. The Likert scale categories were defined as no contrast filling (1), slight filling 25% (2), moderate 50% filling (3), subtotal filling 75% (4) and complete contrast media opacification (5). SD: standard deviation; Q1: first quartile (25%); Q3: third quartile (75%).
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Acetated Ringer‘s solution group #1 3 4 #2 4 5 #3 2 2 #4 4 4 #5 4 5 #6 4 5 #7 4 5 #8 5 5 #9 5 4 #10 4 4 Mean ± SD 3.9 ± 0.99 4.3 ± 0.95 Median (Q1—Q3) 4 (4—4) 4.5 (4—5) Polyethylene glycol group #1 4 5 #2 3 5 3 5 #3 #4 5 5 #5 3 5 #6 4 3 #7 3 5 #8 4 5 #9 4 5 #10 5 5 Mean ± SD 3.8 ± 0.79 4.8 ± 0.63 Median (Q1—Q3) 4 (3—4) 5 (5—5) Wilcoxon rank sum test for group comparison P-value 0.65 0.09
Right CCA
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Comparison of the Likert scale rating regarding image quality of acetated Ringer solution and polyethylene glycol-based contrast agent mixtures.
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Table 1
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Acetated Ringer-based contrast for postmortem CTA
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Figure 1. 55-year-old male deceased of natural death (patient # 8). A. CT image in the axial plane obtained during the arterial phase following injection of acetated Ringer (AR) mixture. Excellent contrast within the right coronary artery (black arrow) is seen. B. At a different level of slice, CT image in the axial plane obtained during the arterial phase following injection of AR mixture shows no contrast material within the left coronary artery (white arrow).
Figure 2. 63-year-old male deceased of natural death (patient #1). A. CT image in the axial plane obtained during the arterial phase following injection of polyethylene glycol (PEG)-based mixture shows excellent contrast within the left coronary artery (black arrow). B. CT image in the axial plane obtained during the arterial phase following injection of PEG-based mixture shows no contrast in the right coronary artery (white arrow).
Artifacts
Autopsy assessment
In both groups, intraluminal layering effect was observed in large vessels and heart chambers. AR settled on top of the sedimented blood particles, whereas PEG was located posterior to the intravascular settled blood in all cadavers. Severe extravasation occurred in all (10/10; 100%) cadavers the AR group but in none (0/10; 0%) in the PEG group (P < 0.001) (Figs. 3 and 4). Severe extravasation affected the pancreas in all cadavers of the AR group; with large, peripancreatic contrast material accumulations in 3 cadavers (Fig. 3). In the AR group, the gastric mucosa also showed massive enhancement of the gastric folds and mucosa and slight leakage in 3/10 cadavers (30%) and severe extravasation into the stomach in 1/10 cadaver (10%). Enhancement of pharyngeal, esophageal, duodenal mucosa, small bowel and colon was strong in all cadavers. In the AR group, leakage of contrast material into the trachea was present in three cadavers and in three cadavers at the level of the pharynx, with one of the three showing both. Intramuscular diffuse leakage was present in 4/10 cadavers (40%) in the AR group involving the following musculature: biceps, triceps, pectoral, serratus anterior, scalene, trapezius and gluteal muscles. None of the cadavers showed external signs of putrefaction. Intraluminal gas was present in 8/10 cadavers (80%) in the AR group and 6/10 (60%) in the PEG group (P = 0.628).
At autopsy, visual alteration was observed in 4/10 cadavers (40%) in the AR group and in 9/10 cadavers (90%) in the PEG group (P = 0.057). Haptic alterations were observed in 3/10 cadavers (30%) in the AR group and 10/10 cadavers (100%) in the PEG group (P = 0.003). In the AR group, visual alteration consisted in orbital fluid extravasation (n = 1) and pharyngeal extravasation (n = 3) and thereof one with tracheal extravasation with consecutively oral leakage. Haptic alterations consisted in softened wobbly consistency changes in general. Organ changes were specified as increased consistency of the heart with reddishbrownish coloration (n = 1) and the kidneys (n = 1) as well as edematous swelling of the pancreas with brownish coloration (n = 1). A subcutaneous hematoma had a more glazed appearance (n = 1). The intravascular content was increasingly liquefied in 3/10 cadavers (30%). In the PEG group a visual reddish ‘‘vivid appearance’’ discoloration, especially of the face, was observed in 9/10 cadavers (90%). Haptic alterations were described as slippery and oily in all cadavers. Macroscopic changes were described in 6/10 cadavers (60%) with increased consistency of the heart, liver, pancreas, musculature and parchment changes of the dura and with patchy discoloration of the heart muscle and musculature (Fig. 5). Intraluminal changes
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Figure 3. 37-year-old male deceased of natural death (patient #7). A. CT image in the axial plane obtained during the arterial phase following injection of acetated Ringer (AR) mixture reveals peripancreatic contrast material extravasation (white arrow). B. CT image in the axial plane obtained during the venous phase following injection of AR mixture shows increasing extravasation of AR contrast material (white arrow). Note the mucosal enhancement and the lack of ubiquitous parenchymal enhancement during the venous phase (e.g., liver).
Figure 4. 63-year-old male deceased of natural death (patient #3). A. CT image in the axial plane obtained during the arterial phase following injection of polyethylene glycol (PEG)-based mixture shows subtle pancreatic enhancement (arrow) as well as of left kidney. B. CT image in the axial plane obtained during the venous phase following injection of PEG-based mixture shows no peripancreatic leakage (arrow) but a distinct parenchymal enhancement of the liver, kidney, pancreas and no over enhancement of mucosal tissue.
Figure 5. 47-year-old male deceased of natural death (patient #8) who underwent postmortem CT angiography with polyethylene glycolbased mixture. A—C. Photographs show gross features of autopsy specimens. A. Cast-like cruor are present within the lung simultaneously with slippery haptic changes. The liver (B) and the myocardium (C) show patchy discoloration.
were observed in 9/10 cadavers (90%) presenting as castlike, dehydrated postmortem clots (Fig. 5).
Discussion We found that PEG showed better diagnostic features than crystalloid AR. AR as a new base for a contrast media mixture for PMCTA, provided advantages on postmortem contrast-enhanced imaging but displayed multiple drawbacks compared to the PEG-based contrast medium mixture. Regarding image quality, both contrast medium mixtures
showed gravity-dependent features. AR provided excellent contrast within the right coronary artery but limited contrast within the left coronary artery and vice versa for PEG. This drawback may be overcome by turning the corpse from the supine to prone position, resulting in a successful redistribution of blood and contrast media mixture. In addition, the use of a multiphasic protocol, with a third or even fourth dynamic phase with contrast media mixture application may allow for an entire volume filling as suggested by Grabherr et al. for Angiofil® Macro [15]. However, it is unclear to what extent a multiphasic protocol would visually alter the corpse.
Please cite this article in press as: Péporté ARJ, et al. Evaluation of an acetated Ringer-based contrast material mixture for postmortem computed tomography angiography. Diagnostic and Interventional Imaging (2020), https://doi.org/10.1016/j.diii.2020.01.009
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Acetated Ringer-based contrast for postmortem CTA In our study, we found that the dynamic patterns of AR are similar to those described for Angiofil® Macro [25]. Further studies comparing AG and Angiofil® Macro are needed. PEG showed significant results in contrasting the supraaortal vasculature and extra- and intracranial arteries, but the venous system was better depicted using AR, probably due to better venous distribution owing to a lower viscosity. Extravasation due to the use of AR severely impairs the diagnostic value of PMCTA as, should they be present, trauma or lesions to the airways and gastrointestinal tract may be undetectable. In addition, AR may not be applicable to putrefied cadavers. The presence of contrast medium mixture leakage did not correlate to the length of the postmortem interval between time of death and PMCTA. In our study, PEG, showed no leakage, and our current results are consistent with those of Jackowski et al. and Ross et al. [20,17,28]. Intravascular or intrahepatic gas was attributed to normal postmortem changes and does not necessarily correlate with the used contrast media mixture. The slight amount of gas did not impair image quality. Franckenberg et al. have compared PEG-based contrast media mixture and Angiofil® Macro in decomposed cadavers and found that Angiofil® Macro provided more distinct enhancement of the gastric mucosa [19]. However, the diagnostic value of PMCTA was affected by the stage of decomposition [19]. The same study stated that PMCTA in decomposed bodies is feasible, even for heavily decomposed cadavers [19]. On the basis of our results, there is no better postmortem contrast media mixture yet. The highly viscous PEG-based contrast media mixture has the disadvantage of partially severe haptic, visual and macroscopic alterations at autopsy but the benefit of good to excellent imaging features (except for the right coronary artery) and an improved tissue enhancement of the brain, kidneys and myocardium lead to a yet unclear diagnostic benefit [20,28,29]. Our study shows that AR has better distribution in the venous system and provides excellent opacification of the right coronary artery with the major drawback of strong mucosal enhancement and airway as well as digestive system leakage that impairs a proper diagnostic radiological report. Histological alteration of histology samples caused by PEG contrast media mixture has been ruled out according to Higgins et al. [30] and Ross et al. [20]. In our study standard histology was not evaluated as based on literature no adverse effects of either contrast media mixtures had to be expected. Histology was only taken if necessary, for the evaluation of the cause of death during autopsy and therefore not consistently. Considerations for the development of a future improved contrast media mixture should potentially include a mixture of high and low viscosity carrier substances (e.g., PEG and hypertonic crystalloid or saline solution). Another hypothesis would be to use icodextrin, which is a starchderived, branched, water-soluble glucose polymer with an average molecular weight between 5000 to 6500 g/mol (PEG 600 g/mol). Icodextrin is used for peritoneal dialysis and reduces extracellular water, which could be beneficial for PMCTA and avoidance of leakage [31]. Further, if oily, not hydrophilic, solutions are used, attention has to be paid to
7 the environmental biodegradability of the substances and potential histologically alterations. A limitation of this study is the limited study population and the lack of full age and cause of death in the matched control group. Additionally, not all major vascular levels and peripheral vasculature were evaluated. In conclusion, the AR-based contrast media mixture did not prove superior to PEG regarding diagnostic image quality but altered autopsy findings contrary to the PEG-based contrast media mixture. Both carrier substances (AR and PEG) had specific substance-related artifacts and dependent opacification of the coronary arteries, but PEG did not cause extravasation. Therefore, PEG-based contrast media mixture should preferably be used for diagnostic benefits. The autopsy technicians and forensic pathologist get adapted to the alterations caused by PEG over time — until an improved contrast media mixture is established.
Ethical statement Ethical approval was obtained.
Funding No financial support.
Author contributions Péporté ARJ: • investigation: equal; • methodology: equal; • supervision: equal; • validation: equal; • writing — original draft: equal; • writing — review and editing: lead. • • • • • •
Gascho D: conceptualization: equal; data curation: lead; formal analysis: lead; resources: lead; supervision: equal; writing — review and editing: equal.
Stamou S: • supervision: equal; • validation: equal; • writing — review and editing: supporting. • • • •
Bensler S: project administration: equal; validation: equal; writing — original draft: supporting; writing — review and editing: supporting.
• • • • •
Thali MJ: conceptualization: equal; investigation: lead; methodology: supporting; project administration: supporting; writing — review and editing: supporting.
Please cite this article in press as: Péporté ARJ, et al. Evaluation of an acetated Ringer-based contrast material mixture for postmortem computed tomography angiography. Diagnostic and Interventional Imaging (2020), https://doi.org/10.1016/j.diii.2020.01.009
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• • • •
Leschka S: conceptualization: supporting; project administration: supporting; writing — original draft: supporting; writing — review and editing: supporting.
• • • • • • • • • •
Flach PM: conceptualization: lead; funding acquisition: lead; investigation: lead; methodology: lead; project administration: lead; supervision: lead; validation: lead; visualization: lead; writing — original draft: lead; writing — review and editing: lead.
Disclosure of interest The authors declare that they have no competing interest.
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9 the liver, kidneys and left ventricle of the heart. Forensic Sci Med Pathol 2017;13:317—27. [31] Cnossen TT, Konings CJ, van der Sande FM, Leunissen KM, Kooman JP. Clinical effects of icodextrin in peritoneal dialysis. NDT Plus 2008;1 [iv18-22].
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ORIGINAL ARTICLE /Forensic medicine
Evaluation of an acetated Ringer-based contrast material mixture for postmortem computed tomography angiography A.R.J. Péporté a, D. Gascho b, S. Stamou b,c, S. Bensler d, M.J. Thali b, S. Leschka a, P.M. Flach a,b,∗ a
Clinic for Radiology and Nuclear Medicine, Cantonal Hospital Saint-Gallen, 9007 Saint-Gallen, Switzerland b Institute of Forensic Medicine, Virtopsy, University of Zurich, 8057 Zurich, Switzerland c Department of Radiology, Lake Hospital Horgen, 8810 Horgen, Switzerland d Institute for Radiology, Cantonal Hospital Baden, 5404 Baden, Switzerland
KEYWORDS Autopsy; Postmortem computed tomography angiography (PMCTA); Virtopsy; Contrast media mixture; Postmortem computed tomography (PMCT)
Abstract Purpose: The purpose of this study was to compare an established postmortem contrast medium mixture based on polyethylene glycol (PEG) to an isotonic crystalloid with acetated Ringer solution (AR) as the base, both mixed with water-soluble iodinated contrast medium for postmortem computed tomography angiography (PMCTA) with the aim to avoid alterations of the corpse during autopsy. Materials and methods: The study included 20 cadavers; 10 had PMCTA with AR and 10 with PEG. PMCTA images were analyzed with respect to image quality, vascular contrast patterns and artifacts. Autopsy was evaluated for visual, organ, vessel and haptic alterations. The Wilcoxon rank sum test was used to search for differences in image quality between the two groups. Statistical significance was set at P < 0.05. Results: AR provided excellent contrast within the right coronary artery (P < 0.001) but a lack of contrast within the left coronary artery (P = 0.008) whereas PEG showed the opposite. A better image quality was observed in the PEG group by comparison with the AR group for right common carotid artery (P = 0.03), left common carotid artery (P = 0.01) and left coronary artery (P = 0.008). No differences were found for ascending aorta (P = 0.65), aortic arch (P = 0.09), right circle of Willis (P = 0.17), left circle of Willis (P = 0.08), inferior vena cava (P = 0.07) and abdominal aorta (P = 0.08). Severe extravasation occurred in all (10/10; 100%) cadavers in the AR group but in none (0/10; 0%) in the PEG group (P < 0.001). At autopsy, visual alteration with lilac discoloration of the face was observed in 4/10 cadavers (40%) in the AR group and in 9/10 cadavers (90%) in the PEG group (P = 0.057). Haptic alterations were observed in 3/10 cadavers (30%) in the AR group and 10/10 cadavers (100%) in the PEG group (P = 0.003).
∗ Corresponding author. Clinic for radiology and nuclear medicine, Cantonal hospital Saint-Gallen, Haus 03, Rorschacher Strasse 95, 9007 Saint-Gallen, Switzerland. E-mail address: patricia.fl[email protected] (P.M. Flach).
https://doi.org/10.1016/j.diii.2020.01.009 2211-5684/© 2020 Soci´ et´ e franc ¸aise de radiologie. Published by Elsevier Masson SAS. All rights reserved.
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A.R.J. Péporté et al. Conclusion: AR results in contrast medium mixture extravasation in all cadavers, but PEG altered the autopsy more severely. Both carrier substances result in specific substance-related artifacts and dependent opacification of the coronary arteries, but PEG is recommended for PMCTA exclusively with regard to diagnostic imaging. © 2020 Soci´ et´ e franc ¸aise de radiologie. Published by Elsevier Masson SAS. All rights reserved.
Postmortem computed tomography (PMCT) is currently part of the routine examination in forensic medicine [1—7]. PMCT has a potential to support forensic autopsy owing to superior detection of gas embolism and accumulations, fractures and fracture patterns, foreign bodies and even hemorrhage after large vessel ruptures or trauma [8—13]. However, the depiction of vasculature and soft tissue is limited when using unenhanced PMCT, and therefore PMCT angiography (PMCTA) was introduced to increase the accuracy of PMCT [14—23]. Although extensive research has been performed, scarce literature is available on potential artifacts and alterations of the corpses during PMCTA procedures. Bruguier et al. described technique-related artifacts and pitfalls in multiphase PMCTA using Angiofil® (Fumedica AG) [22]. These researchers reported incomplete contrast filling of the cerebral venous system, contrast agent layering in the lumen of the thoracic aorta and enhancement of the gastrointestinal mucosa [24]. However, these imaging findings were undermined by a previous publication by Grabherr et al. that reported exceedingly rare extravasation of Angiofil® when using an appropriate perfusion protocol for PMCTA [15,25]. No studies have described the alterations of the corpse that are seen during autopsy. In daily routine, unwanted alterations are often observed. They include cast-like cruor, increased organ consistency, and macroscopic changes such as patchy organ discoloration, which is especially critical for myocardial assessment, and a slippery touch under polyethylene glycol (PEG) solution-based contrast agent. In clinical emergency settings, slightly hypotonic crystalloid solutions such as acetated Ringer solution (AR) are preferably used for intravascular volume replacement therapy. The buffer ion in AR is acetate and keeps the potential of hydrogen (pH) value up, whereas in a postmortem cadaver, the pH drops significantly over time [26,27]. The purpose of this study was to evaluate an established postmortem contrast media mixture based on PEG compared to isotonic crystalloid AR solution as the base, both mixed with water-soluble iodinated contrast medium for PMCTA in order to avoid alterations of the corpse during autopsy.
Materials and methods Study cadavers The responsible justice department approved PMCT and PMCTA examination and mandated forensic autopsy. Ethical approval was obtained. A prospective analysis was
performed over a 3-year period (2014—2016). The exclusion criteria were decomposition, severe injuries and known trauma, thermal injuries, and age younger than 18 years. Based on pre-autopsy subject history, cadavers with presumed natural death were selected. The time of death was either known as documented by the minute or was estimated based on legal inspection. If estimated, the mean was used between the minimal and maximal estimated time of death. The final AR solution group included 10 cadavers. There were 6 males and 4 females, with a mean age of 57.6 ± 12.02 (standard deviation [SD)) years (median, 56 years; range: 37—76 years). Deaths were due to natural death (n = 8) as the manner of death with cardiac arrest as the cause of death, suicide (n = 1) or accidental with alcohol mixed with illicit drug intoxication (n = 1). The control group (PEG) included 10 cadavers. There were 6 males and 4 females with a mean age of 54.1 ± 9.59 (SD) years (median, 54 years; range: 34—66 years). Deaths were due to cardiac arrest (n = 8) or central regulatory failure (n = 2).
Imaging procedures PMCT technique Each subject underwent PMCT and PMCTA using a dualsource 2 × 128 section CT unit (Somatom Flash® Definition, Siemens Healthineers) with standard parameters at a 100 kVp tube voltage and 350 mAs tube current [13]. The pitch factor was 0.35, and the rotation time was 0.5 s. All reconstructions were obtained in a soft tissue window with a soft kernel and bone window with a hard kernel in an adjusted field of view [13]. A multi-modality workstation was used for image review and reporting (Syngovia® , Version VB10A, Siemens Healthineers).
Contrast media mixture The control group received an established contrast media mixture with a solution of polyethylene glycol (PEG 200, Schaerer and Schlaepfer AG) and water-soluble iodinated contrast agent (ioversol, Optiray 300® , Guerbet) at a ratio of 1:20. The experimental group received a contrast media mixture of AR solution (Fresenius Kabi AG) with the same water-soluble iodinated contrast agent as in the control group at a ratio of 1:17 (60 mL/1000 mL). Both contrast
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Acetated Ringer-based contrast for postmortem CTA medium mixtures had an attenuation value of 350 Hounsfield units (HU).
Angiography technique for PMCTA After unilateral inguinal skin incision, the right or left femoral artery was cannulated via a retrograde approach using a 14-Fr pediatric cannula in polyurethane (Sorin Group) and the femoral vein using an antegrade approach using a 16-Fr cannula (Sorin Group) by the autopsy technicians. The vessels were then ligated to the cannulas, which were connected to a pressure-controlled heart-lung machine (Stöckert-Shiley Computer Aided Perfusion System, Stöckert AG) at a mean flow rate of 800 mL/min by means of an 18-G needle at approximately 60 mm Hg [20]. The administered contrast medium mixture volume varied according to the deceased habitus, stature and weight and was between 1.5- and 3-L in total (mean 2.3 L, median 2.325 L). Because the venous system was prone to more volume administration than the arterial system, the arterial system was filled first, followed by the venous system administration with the arterial cannula left open. The cannulas were left in place after the angiographic procedure, removed and sutured during autopsy. The autopsy technicians drew femoral blood and, if needed, musculature at the same time whilst incising and placing the cannulas prior to PMCTA.
Radiological assessment Radiological analysis and reporting were performed by a forensic experienced board-certified radiologist and a board-certified general radiologist. Assessment was performed in consensus reading by both radiologists. The PEG control group and AR evaluation group were first assessed for image quality using a 5-category Likert-type scale on the basis of intravascular contrast and then for the presence of artifacts such as layering effects of the contrast media mixture within the vasculature and the postmortem settled blood particles, contrast media extravasation and mucosal enhancement within the respiratory, aero-digestive and gastrointestinal tract as well as musculature of the shoulder girdle, upper thorax and gluteal musculature. Physiologically postmortem occurring gas accumulation within the bowel lumen or intrahepatic was evaluated. The Likert scale categories were defined as no contrast filling (score of 1), slight filling 25% (score of 2), moderate 50% filling (score of 3), subtotal filling 75% (score of 4) and complete contrast media opacification (score of 5).
Autopsy assessment Conventional autopsy was used as the standard of reference. It included dissection of the three body cavities (skull, thorax and abdomen). After dissection, a board-certified forensic pathologist, a resident and an autopsy technician provided consensus opinion regarding visual alteration of the corpse, macroscopic organ and vessel changes and haptic alterations blinded to the contrast medium mixture used. Histology and toxicology were not consistently performed and therefore not included in this study.
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Statistical analysis Quantitative variables were expressed as means ± SD, median, first quartile (Q1) third quartiles (Q3) and ranges. Differences in quantitative variables were performed using analysis of variance and differences in qualitative variables with the Fisher exact test. The Wilcoxon rank sum test was used to search for differences in image quality between the two groups. Statistical significance was set at P < 0.05.
Results Study cadavers In the AR solution group, the mean time interval between the time of death and performance of PMCTA was 43.4 ± 29.6 (SD) hours (range: 5.3—92.2 hours; median, 38.4 hours; Q1, 17 hours; Q3, 65 hours) and the mean time interval between death and autopsy was 45 ± 31.8 (SD) hours (range: 6.3—94.3 hours; median, 41 hours; Q1, 18 hours; Q3, 74.5 hours). In the PEG group, the mean time interval between the time of death to PMCTA of 46.0 ± 24.8 (SD) hours (range: 16—92 hours; median, 50 hours; Q1, 19.1 hours; Q3, 62 hours) and the mean time interval between death and autopsy was 48 ± 26.3 (SD) hours (range: 16.4—96.3 hours; median, 52.3 hours; Q1, 19.5 hours; Q3, 63 hours). No differences in time interval between the time of death and performance of PMCTA were found between the two groups (P = 0.834). No differences in time interval between death and autopsy were found between the two groups (P = 0.821). No differences in mean age were found between the two groups (P = 0.481).
Radiological assessment Image quality Table 1 shows the results of the comparison of image quality between the two groups. A better image quality was observed in the AR group by comparison with the PEG group for right coronary artery (P < 0.001). A better image quality was observed in the PEG group by comparison with the AR group for right common carotid artery (P = 0.03), left common carotid artery (P = 0.01) and left coronary artery (P = 0.008). No differences in image quality were found for ascending aorta (P = 0.65), aortic arch (P = 0.09), right circle of Willis (P = 0.17), left circle of Willis (P = 0.08), inferior vena cava (P = 0.07) and abdominal aorta (P = 0.08). AR built a level on top of the posterior settled corpuscular particle in the large vasculature and heart chambers, whereas PEG filled the posterior settled areas and reached the ostium of the left coronary artery but not the right. In the AR group, the right coronary artery showed better degrees of opacification in all cadavers by comparison with the left coronary artery (mean, 2.6; median, 2; Q1—Q3, 1—4.5) (Fig. 1). In the PEG group, the right coronary artery showed lower degrees of opacification compared to the AR group (Fig. 2). One subject in this group died from acute cardiac arrest due to left coronary artery occlusion, thus resulting in poor opacification.
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Asc. aorta
Aortic arch
Left CCA
Right CW
Left CW
Right CA
Left CA
IVC
Abd. Aorta
3 5 5 2 5 4 5 4 5 5 4.3 ± 1.06 5 (4—5)
3 5 5 2 4 4 5 4 5 5 4.2 ± 1.03 4.5 (4—5)
2 5 1 5 5 5 5 5 5 5 4.3 ± 1.49 5 (5—5)
2 5 5 5 5 5 5 4 3 5 4.4 ± 1.07 5 (4.25—5)
5 5 5 5 5 5 5 5 5 5 5.0 ± 0 5 (5—5)
1 5 3 5 1 1 2 1 2 5 2.6 ± 1.78 2 (1—4.5)
4 5 5 5 5 5 5 4 5 5 4.8 ± 0.42 5 (5—5)
5 3 3 4 5 5 5 5 5 5 4.5 ± 0.85 5 (4.25—5)
5 5 5 5 5 5 5 5 5 5 5.0 ± 0 5 (5—5)
5 5 5 5 5 5 5 5 5 5 5.0 ± 0 5 (5—5)
5 5 5 5 5 5 5 5 5 5 5.0 ± 0 5 (5—5)
5 5 5 5 5 5 5 5 5 5 5.0 ± 0 5 (5—5)
1 5 1 1 1 3 5 2 2 2 2.3 ± 1.57 2 (1—2.75)
5 5 5 5 5 5 2 5 5 5 4.7 ± 0.95 5 (5—5)
4 4 4 4 5 5 2 5 5 4 4.2 ± 0.92 4 (4—5)
5 5 5 5 5 5 5 5 5 5 5.0 ± 0 5 (5—5)
0.03
0.01
0.17
0.08
<0.001
0.008
0.07
0.08
A.R.J. Péporté et al.
Asc. Aorta: ascending aorta; CCA: common carotid artery; CW: circle of Willis; CA: coronary artery; IVC: inferior vena cava; Abd. Aorta: abdominal aorta. The Likert scale categories were defined as no contrast filling (1), slight filling 25% (2), moderate 50% filling (3), subtotal filling 75% (4) and complete contrast media opacification (5). SD: standard deviation; Q1: first quartile (25%); Q3: third quartile (75%).
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Acetated Ringer‘s solution group #1 3 4 #2 4 5 #3 2 2 #4 4 4 #5 4 5 #6 4 5 #7 4 5 #8 5 5 #9 5 4 #10 4 4 Mean ± SD 3.9 ± 0.99 4.3 ± 0.95 Median (Q1—Q3) 4 (4—4) 4.5 (4—5) Polyethylene glycol group #1 4 5 #2 3 5 3 5 #3 #4 5 5 #5 3 5 #6 4 3 #7 3 5 #8 4 5 #9 4 5 #10 5 5 Mean ± SD 3.8 ± 0.79 4.8 ± 0.63 Median (Q1—Q3) 4 (3—4) 5 (5—5) Wilcoxon rank sum test for group comparison P-value 0.65 0.09
Right CCA
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Comparison of the Likert scale rating regarding image quality of acetated Ringer solution and polyethylene glycol-based contrast agent mixtures.
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Table 1
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Acetated Ringer-based contrast for postmortem CTA
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Figure 1. 55-year-old male deceased of natural death (patient # 8). A. CT image in the axial plane obtained during the arterial phase following injection of acetated Ringer (AR) mixture. Excellent contrast within the right coronary artery (black arrow) is seen. B. At a different level of slice, CT image in the axial plane obtained during the arterial phase following injection of AR mixture shows no contrast material within the left coronary artery (white arrow).
Figure 2. 63-year-old male deceased of natural death (patient #1). A. CT image in the axial plane obtained during the arterial phase following injection of polyethylene glycol (PEG)-based mixture shows excellent contrast within the left coronary artery (black arrow). B. CT image in the axial plane obtained during the arterial phase following injection of PEG-based mixture shows no contrast in the right coronary artery (white arrow).
Artifacts
Autopsy assessment
In both groups, intraluminal layering effect was observed in large vessels and heart chambers. AR settled on top of the sedimented blood particles, whereas PEG was located posterior to the intravascular settled blood in all cadavers. Severe extravasation occurred in all (10/10; 100%) cadavers the AR group but in none (0/10; 0%) in the PEG group (P < 0.001) (Figs. 3 and 4). Severe extravasation affected the pancreas in all cadavers of the AR group; with large, peripancreatic contrast material accumulations in 3 cadavers (Fig. 3). In the AR group, the gastric mucosa also showed massive enhancement of the gastric folds and mucosa and slight leakage in 3/10 cadavers (30%) and severe extravasation into the stomach in 1/10 cadaver (10%). Enhancement of pharyngeal, esophageal, duodenal mucosa, small bowel and colon was strong in all cadavers. In the AR group, leakage of contrast material into the trachea was present in three cadavers and in three cadavers at the level of the pharynx, with one of the three showing both. Intramuscular diffuse leakage was present in 4/10 cadavers (40%) in the AR group involving the following musculature: biceps, triceps, pectoral, serratus anterior, scalene, trapezius and gluteal muscles. None of the cadavers showed external signs of putrefaction. Intraluminal gas was present in 8/10 cadavers (80%) in the AR group and 6/10 (60%) in the PEG group (P = 0.628).
At autopsy, visual alteration was observed in 4/10 cadavers (40%) in the AR group and in 9/10 cadavers (90%) in the PEG group (P = 0.057). Haptic alterations were observed in 3/10 cadavers (30%) in the AR group and 10/10 cadavers (100%) in the PEG group (P = 0.003). In the AR group, visual alteration consisted in orbital fluid extravasation (n = 1) and pharyngeal extravasation (n = 3) and thereof one with tracheal extravasation with consecutively oral leakage. Haptic alterations consisted in softened wobbly consistency changes in general. Organ changes were specified as increased consistency of the heart with reddishbrownish coloration (n = 1) and the kidneys (n = 1) as well as edematous swelling of the pancreas with brownish coloration (n = 1). A subcutaneous hematoma had a more glazed appearance (n = 1). The intravascular content was increasingly liquefied in 3/10 cadavers (30%). In the PEG group a visual reddish ‘‘vivid appearance’’ discoloration, especially of the face, was observed in 9/10 cadavers (90%). Haptic alterations were described as slippery and oily in all cadavers. Macroscopic changes were described in 6/10 cadavers (60%) with increased consistency of the heart, liver, pancreas, musculature and parchment changes of the dura and with patchy discoloration of the heart muscle and musculature (Fig. 5). Intraluminal changes
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Figure 3. 37-year-old male deceased of natural death (patient #7). A. CT image in the axial plane obtained during the arterial phase following injection of acetated Ringer (AR) mixture reveals peripancreatic contrast material extravasation (white arrow). B. CT image in the axial plane obtained during the venous phase following injection of AR mixture shows increasing extravasation of AR contrast material (white arrow). Note the mucosal enhancement and the lack of ubiquitous parenchymal enhancement during the venous phase (e.g., liver).
Figure 4. 63-year-old male deceased of natural death (patient #3). A. CT image in the axial plane obtained during the arterial phase following injection of polyethylene glycol (PEG)-based mixture shows subtle pancreatic enhancement (arrow) as well as of left kidney. B. CT image in the axial plane obtained during the venous phase following injection of PEG-based mixture shows no peripancreatic leakage (arrow) but a distinct parenchymal enhancement of the liver, kidney, pancreas and no over enhancement of mucosal tissue.
Figure 5. 47-year-old male deceased of natural death (patient #8) who underwent postmortem CT angiography with polyethylene glycolbased mixture. A—C. Photographs show gross features of autopsy specimens. A. Cast-like cruor are present within the lung simultaneously with slippery haptic changes. The liver (B) and the myocardium (C) show patchy discoloration.
were observed in 9/10 cadavers (90%) presenting as castlike, dehydrated postmortem clots (Fig. 5).
Discussion We found that PEG showed better diagnostic features than crystalloid AR. AR as a new base for a contrast media mixture for PMCTA, provided advantages on postmortem contrast-enhanced imaging but displayed multiple drawbacks compared to the PEG-based contrast medium mixture. Regarding image quality, both contrast medium mixtures
showed gravity-dependent features. AR provided excellent contrast within the right coronary artery but limited contrast within the left coronary artery and vice versa for PEG. This drawback may be overcome by turning the corpse from the supine to prone position, resulting in a successful redistribution of blood and contrast media mixture. In addition, the use of a multiphasic protocol, with a third or even fourth dynamic phase with contrast media mixture application may allow for an entire volume filling as suggested by Grabherr et al. for Angiofil® Macro [15]. However, it is unclear to what extent a multiphasic protocol would visually alter the corpse.
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Acetated Ringer-based contrast for postmortem CTA In our study, we found that the dynamic patterns of AR are similar to those described for Angiofil® Macro [25]. Further studies comparing AG and Angiofil® Macro are needed. PEG showed significant results in contrasting the supraaortal vasculature and extra- and intracranial arteries, but the venous system was better depicted using AR, probably due to better venous distribution owing to a lower viscosity. Extravasation due to the use of AR severely impairs the diagnostic value of PMCTA as, should they be present, trauma or lesions to the airways and gastrointestinal tract may be undetectable. In addition, AR may not be applicable to putrefied cadavers. The presence of contrast medium mixture leakage did not correlate to the length of the postmortem interval between time of death and PMCTA. In our study, PEG, showed no leakage, and our current results are consistent with those of Jackowski et al. and Ross et al. [20,17,28]. Intravascular or intrahepatic gas was attributed to normal postmortem changes and does not necessarily correlate with the used contrast media mixture. The slight amount of gas did not impair image quality. Franckenberg et al. have compared PEG-based contrast media mixture and Angiofil® Macro in decomposed cadavers and found that Angiofil® Macro provided more distinct enhancement of the gastric mucosa [19]. However, the diagnostic value of PMCTA was affected by the stage of decomposition [19]. The same study stated that PMCTA in decomposed bodies is feasible, even for heavily decomposed cadavers [19]. On the basis of our results, there is no better postmortem contrast media mixture yet. The highly viscous PEG-based contrast media mixture has the disadvantage of partially severe haptic, visual and macroscopic alterations at autopsy but the benefit of good to excellent imaging features (except for the right coronary artery) and an improved tissue enhancement of the brain, kidneys and myocardium lead to a yet unclear diagnostic benefit [20,28,29]. Our study shows that AR has better distribution in the venous system and provides excellent opacification of the right coronary artery with the major drawback of strong mucosal enhancement and airway as well as digestive system leakage that impairs a proper diagnostic radiological report. Histological alteration of histology samples caused by PEG contrast media mixture has been ruled out according to Higgins et al. [30] and Ross et al. [20]. In our study standard histology was not evaluated as based on literature no adverse effects of either contrast media mixtures had to be expected. Histology was only taken if necessary, for the evaluation of the cause of death during autopsy and therefore not consistently. Considerations for the development of a future improved contrast media mixture should potentially include a mixture of high and low viscosity carrier substances (e.g., PEG and hypertonic crystalloid or saline solution). Another hypothesis would be to use icodextrin, which is a starchderived, branched, water-soluble glucose polymer with an average molecular weight between 5000 to 6500 g/mol (PEG 600 g/mol). Icodextrin is used for peritoneal dialysis and reduces extracellular water, which could be beneficial for PMCTA and avoidance of leakage [31]. Further, if oily, not hydrophilic, solutions are used, attention has to be paid to
7 the environmental biodegradability of the substances and potential histologically alterations. A limitation of this study is the limited study population and the lack of full age and cause of death in the matched control group. Additionally, not all major vascular levels and peripheral vasculature were evaluated. In conclusion, the AR-based contrast media mixture did not prove superior to PEG regarding diagnostic image quality but altered autopsy findings contrary to the PEG-based contrast media mixture. Both carrier substances (AR and PEG) had specific substance-related artifacts and dependent opacification of the coronary arteries, but PEG did not cause extravasation. Therefore, PEG-based contrast media mixture should preferably be used for diagnostic benefits. The autopsy technicians and forensic pathologist get adapted to the alterations caused by PEG over time — until an improved contrast media mixture is established.
Ethical statement Ethical approval was obtained.
Funding No financial support.
Author contributions Péporté ARJ: • investigation: equal; • methodology: equal; • supervision: equal; • validation: equal; • writing — original draft: equal; • writing — review and editing: lead. • • • • • •
Gascho D: conceptualization: equal; data curation: lead; formal analysis: lead; resources: lead; supervision: equal; writing — review and editing: equal.
Stamou S: • supervision: equal; • validation: equal; • writing — review and editing: supporting. • • • •
Bensler S: project administration: equal; validation: equal; writing — original draft: supporting; writing — review and editing: supporting.
• • • • •
Thali MJ: conceptualization: equal; investigation: lead; methodology: supporting; project administration: supporting; writing — review and editing: supporting.
Please cite this article in press as: Péporté ARJ, et al. Evaluation of an acetated Ringer-based contrast material mixture for postmortem computed tomography angiography. Diagnostic and Interventional Imaging (2020), https://doi.org/10.1016/j.diii.2020.01.009
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A.R.J. Péporté et al.
• • • •
Leschka S: conceptualization: supporting; project administration: supporting; writing — original draft: supporting; writing — review and editing: supporting.
• • • • • • • • • •
Flach PM: conceptualization: lead; funding acquisition: lead; investigation: lead; methodology: lead; project administration: lead; supervision: lead; validation: lead; visualization: lead; writing — original draft: lead; writing — review and editing: lead.
Disclosure of interest The authors declare that they have no competing interest.
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Please cite this article in press as: Péporté ARJ, et al. Evaluation of an acetated Ringer-based contrast material mixture for postmortem computed tomography angiography. Diagnostic and Interventional Imaging (2020), https://doi.org/10.1016/j.diii.2020.01.009