DOI:10.2214/AJR.07.3082
AJR 2008; 190:1380-1389
© American Roentgen Ray Society
Postmortem Whole-Body CT Angiography: Evaluation of Two Contrast Media Solutions
Steffen Ross1,
Danny Spendlove1,
Stephan Bolliger1,
Andreas Christe2,
Lars Oesterhelweg1,
Silke Grabherr3,
Michael J. Thali1 and
Erich Gygax4
1 Centre for Forensic Imaging and Virtopsy, Institute of Forensic Medicine,
University of Bern, Buehlstrasse 20, CH-3012 Bern, Switzerland.
2 Department of Radiology, Inselspital Bern, University of Bern, Bern,
Switzerland.
3 Institute of Forensic Medicine, University of Lausanne, Lausanne,
Switzerland.
4 Clinic for Cardiovascular Surgery, Inselspital Bern, University of Bern, Bern,
Switzerland.
Received August 30, 2007;
accepted after revision November 20, 2007.
Address correspondence to S. Ross
(steffen.ross{at}irm.unibe.ch).
Abstract
OBJECTIVE. The objective of our study was to establish a
standardized procedure for postmortem whole-body CT-based angiography with
lipophilic and hydrophilic contrast media solutions and to compare the results
of these two methods.
MATERIALS AND METHODS. Minimally invasive postmortem CT angiography
was performed on 10 human cadavers via access to the femoral blood vessels.
Separate perfusion of the arterial and venous systems was established with a
modified heart–lung machine using a mixture of an oily contrast medium
and paraffin (five cases) and a mixture of a water-soluble contrast medium
with polyethylene glycol (PEG) 200 in the other five cases. Imaging was
executed with an MDCT scanner.
RESULTS. The minimally invasive femoral approach to the vascular
system provided a good depiction of lesions of the complete vascular system
down to the level of the small supplying vessels. Because of the enhancement
of well-vascularized tissues, angiography with the PEG-mixed contrast medium
allowed the detection of tissue lesions and the depiction of vascular
abnormalities such as pulmonary embolisms or ruptures of the vessel wall.
CONCLUSION. The angiographic method with a water-soluble contrast
medium and PEG as a contrast-agent dissolver showed a clearly superior quality
due to the lack of extravasation through the gastrointestinal vascular bed and
the enhancement of soft tissues (cerebral cortex, myocardium, and parenchymal
abdominal organs). The diagnostic possibilities of these findings in cases of
antemortem ischemia of these tissues are not yet fully understood.
Keywords: angiography • contrast media • noninvasive autopsy • postmortem whole-body angiography • virtopsy • virtual autopsy
Introduction
Conventional autopsies are facing increasing objections on behalf of the
families of deceased persons, thus leading to a marked decrease of clinical
autopsies. This, in turn, leads to the loss of a valuable tool for clinical
quality control in evidence-based medicine. Forensic autopsies, which are
commissioned by the district attorney's office (or another comparable
institution) and thus usually cannot be objected to, are also facing
increasing difficulties. Apart from surmountable difficulties such as
objections on behalf of the next of kin and religious groups, the main problem
is reproducibility in court. Currently, autopsy reports are descriptive and
observer dependent and rely on the integrity of the examiner. However, blind
trust in the subjective opinion of medical examiners in court is dwindling,
thus giving rise to calls for a more objective documentation method.
Therefore, a postmortem examination should be as minimally invasive as
possible to reduce the anguish of the next of kin, while still serving quality
control and being reproducible at a later date.
Because cross-sectional imaging techniques, especially CT, have experienced
tremendous improvements since the 1990s, several groups have started to
perform these methods on cadavers with the aim of gaining additional
information to augment autopsy or even to replace conventional autopsy. The
promising results have led to an increased acceptance of postmortem imaging in
the field of forensic pathology.
Indeed, CT has proven to be very useful in diagnosing osseous findings,
foreign bodies, air embolisms, and gross abnormalities of the soft tissue.
MRI, on the other hand, is better suited for the detection of smaller
soft-tissue lesions and organ abnormalities
[1,
2]. CT-guided biopsies for the
histologic evaluation of findings (e.g., cancer research) are easily performed
[3]. One of the last
"blind spots" of postmortem imaging is the displaying of vascular
abnormalities. The unenhanced examination using CT or MRI gives little
information about damage to major vessels. Therefore, conventional, albeit
time-consuming, autopsy techniques are the method of choice for the
examination of the vascular bed of an organ. However, the visualization of the
vascular system of an entire cadaver is technically impossible.
A form of limited postmortem angiography has often augmented the
above-mentioned conventional techniques regarding the vascular bed. Indeed,
this technique has a long history starting with the experiments of Leonardo da
Vinci in the 16th century. Several experiments were made with the injection of
casts, oily liquids, and corpuscular and hydrophilic preparations
[4]. In most cases, isolated
organs were perfused. There are few reports about angiographies of human
fetuses
[5–7].
Although a whole-body angiography would be useful for screening for the
presence of vascular abnormalities, successful complete whole-body postmortem
CT imaging in adults has not been achieved to date.
For this objective, our group studied the implementation of several
contrast media, of which two proved useful: an iodinated oily contrast agent
and a water-soluble iodinated contrast agent
[8–10].
Both agents showed different advantages and disadvantages. The oily solution
offered a longer intravascular phase (more than 72 hours) with the possibility
of an extended interval between injection and imaging. The major drawback was
the unwanted extravasation through damaged vessel walls in areas of early
autolysis (gastrointestinal tract), making correct detection of traumatic
vessel lesions in these areas impossible. The mixture of a water-soluble,
hydrophilic contrast medium with polyethylene glycol (PEG) as a large
molecular (polymerized) carrier substance showed the potential to overcome the
already known rapid penetration through the undamaged vessel wall with
successive edema of the surrounding tissue. We performed the present study to
evaluate the practicability of whole-body angiography with these two contrast
media mixtures and to assess the respective advantages and drawbacks.
Materials and Methods
The responsible justice department and the ethics committee of the
University of Bern approved of this study. Ten cadavers delivered to the
Institute of Forensic Medicine for forensic autopsy were studied
(Table 1). Three were women and
seven were men. The mean age at time of death was 59.2 years, ranging from 25
to 96 years. The mean interval between estimated times of death and imaging
was 29.3 hours, ranging from 12 to 60 hours. A conventional autopsy with
sampling of histologic specimens was performed in every case for a direct
comparison with the radiologic findings. Samples of peripheral blood and urine
were collected before the angiographic procedures.
A compound of paraffin oil and iodized oil (Lipiodol Ultra Fluide, Guerbet)
was administered in the first five bodies in a mixture ratio of 15:1 (mean
radiodensity, 600 H). The remaining five bodies underwent perfusion with a
solution of PEG (PEG 200, Schaerer and Schlaepfer AG) and iopentol (Imagopaque
300, GE Healthcare) in a mixture ratio of 10:1 (mean radiodensity, 600 H). The
radiodensity of the contrast media was raised in comparison with clinical
antemortem examinations for better contrast in the vascular peri phery and
better depiction of small extravasations.
Access to the arterial and venous systems was gained through a unilateral
inguinal incision and preparation of the femoral vessels, with subsequent
retrograde cannulation of the femoral artery and antegrade cannulation of the
femoral vein (arterial, 16-French; venous, 20-French)
(Fig. 1). The fixed cannulas
were con nected to a pressure-controlled modified heart–lung machine
(HL20, Maquet) (Fig. 2). The
arterial can nula was turned around in a second step to inject the arteries
distal from the femoral access point. Perfu sion of the vascular system was
performed using the following parameters. For the head, neck, and thorax
including the upper extremi ties and abdomen: perfu sion volume, 
2,000
mL; pressure gradient, 80 mm Hg; flow rate, 800 mL/min. For the
lower extrem ities: perfusion volume, 400 mL; pressure gradient,
50 mm Hg; flow rate, 200 mL /min.
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Fig. 1 —Photograph shows minimally invasive access to vascular system
through right femoral incision and cannulation of femoral artery (red
arrow) and vein (blue arrow). Removable ligatures ensure
fixation of cannulas and ligation of vessels opened during preparation
process.
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Postmortem imaging was executed on a 6-MDCT scanner (Somaton Emotion 6,
Siemens Medical Solutions). All examinations included a triphasic scanning
protocol (unenhanced, arterial injection, venous injection) in the supine
position. Imaging of the thorax and abdomen with raised arms was performed. A
change to the prone position was per formed in case of incomplete filling of
the coronary arteries. The primary angiographic CT scan followed in every case
directly after the complete administration of the contrast media solution (3
seconds). The second injection (arterial or venous dependent on the case) was
done with a minimum interval of 15 minutes (maximum, 30 minutes). Raw data
acquisition was performed with the following settings: 110 kV; 100 mAs;
collimation, 6 x 1 mm whole body and 6 x 0.5 mm in selected
regions. Image reconstruction was performed in slice thicknesses of 5, 1.25,
and 0.625 mm, each with an increment of half the slice thickness, soft tissue,
and bone-weighted recon struction kernel. Pri mary image review and 3D
reconstructions were performed on a CT work station (Leonardo, Siemens Medical
Solutions). For the intra- and interindividual comparison, a PACS workstation
was used (IDS5, Sectra AB).
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Fig. 3A —Cadaver after osteoclastic craniotomy at right side and
clipping of M1 segment of right medial cerebral artery. (case 1; iodized oil
[Lipiodol, Guerbet] and paraffin oil solution) Maximum-intensity-projection
(MIP) images of cerebral vasculature in axial (A) and coronal
(B) reconstructions show even peripheral vessels are displayed exactly.
Note asymmetric enhancement of vessels in area of craniotomy and
asymmetrically contrasted lentigostriatic branches in coronal reconstruction
(B). Cerebral cortex shows no enhancement. Fetal origin of left
posterior artery is anatomic variant.
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Fig. 3B —Cadaver after osteoclastic craniotomy at right side and
clipping of M1 segment of right medial cerebral artery. (case 1; iodized oil
[Lipiodol, Guerbet] and paraffin oil solution) Maximum-intensity-projection
(MIP) images of cerebral vasculature in axial (A) and coronal
(B) reconstructions show even peripheral vessels are displayed exactly.
Note asymmetric enhancement of vessels in area of craniotomy and
asymmetrically contrasted lentigostriatic branches in coronal reconstruction
(B). Cerebral cortex shows no enhancement. Fetal origin of left
posterior artery is anatomic variant.
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Fig. 4A —Cadaver with subdural hematoma. (case 10; iopentol
[Imagopaque, GE Healthcare] and polyethylene glycol) Axial reconstruction
image (A) shows large, right subdural hematoma (asterisks)
with active extravasation of contrast media solution in anterior parts
(closed arrow). Asymmetric enhancement of cortex and basal ganglia
with depiction of massive midline shift to left can be seen in A and
subfalcial and infratentorial herniation of brain tissue to left (open
arrows) in coronal view (B). Absent cortical enhancement in
supplying area of right anterior cerebral artery and posterior branches of
left medial cerebral arteries suggests antemortem infarction. Note hypodensity
of subdural hematoma due to adaptation of window level and width on enhancing
cortex.
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Fig. 4A —Cadaver with subdural hematoma. (case 10; iopentol
[Imagopaque, GE Healthcare] and polyethylene glycol) Axial reconstruction
image (A) shows large, right subdural hematoma (asterisks)
with active extravasation of contrast media solution in anterior parts
(closed arrow). Asymmetric enhancement of cortex and basal ganglia
with depiction of massive midline shift to left can be seen in A and
subfalcial and infratentorial herniation of brain tissue to left (open
arrows) in coronal view (B). Absent cortical enhancement in
supplying area of right anterior cerebral artery and posterior branches of
left medial cerebral arteries suggests antemortem infarction. Note hypodensity
of subdural hematoma due to adaptation of window level and width on enhancing
cortex.
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Image interpretation was performed by one board-certified radiologist with
2 years of experience in forensic imaging and by an advanced radiologic
resident with 3 years of experience in clinical radiology and 1.5 years of
experience in for ensic CT. Each whole-body data set (unenhanced and arterial
and venous injection) underwent a complete evaluation, similar to an
examination in clinical radiology. For each case, a detailed written report of
the findings was created. Image quality was evaluated by objective parameters
in terms of complete filling of the vessel lumen and obvious iatrogenic
extravasations (gastrointestinal tract, femoral cannulation). Through the
interindividual differences of the postmortem interval and the associated
tissue degradation, the parenchymal enhancement (brain, myocardium, upper
abdominal organs, and peripheric soft tissue) was evaluated as a subjective
criterion.
Results
Head and Neck
Both contrast media solutions showed excellent visualization of the basal
cerebral arteries. Anatomic variants of the circle of Willis and
postinterventional changes with resulting perfusion deficits of the cerebral
arteries (Fig. 3A,
3B) were clearly depicted with
both contrast media solutions. Extravasation into intracerebral hematomas is
suggestive of active bleeding at the time of death. The gray matter of the
brain showed a unique enhancement after the injection of the PEG contrast
solution, which improved visualization of the brain tissue distinctively.
Brain structures that were affected by subfalcial or infratentorial
herniations became much better visualized than in unenhanced CT (Fig.
4A,
4B). This kind of delineation
of the cortex and the basal ganglia was not seen in the cases injected with
the oily contrast compound. The arteriovenous vascularity of the neck was also
clearly depicted by both contrast media solutions. Malignant tissues showed
contrast enhancement after injection of the PEG contrast solution as well, as
seen in a case with a partly necrotic laryngeal carcinoma. The enhancement of
the submandibular glands after injection was a unique finding in the cases
with PEG contrast solution (Fig.
5). Traumatic intramuscular and subcutaneous hematomas
(Fig. 6) were seen
radiographically as an extravasation of both contrast media solutions.
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Fig. 5 —Axial CT image of neck shows partly necrotic laryngeal
carcinoma with enhancing part on left side (dashed circle).
Enhancement of musculature of neck is most likely due to reanimation attempts.
Autopsy showed no evidence of metastatic disease. Note enhancement of right
submandibular gland (arrow). (case 7; iopentol [Imagopaque, GE
Healthcare] and polyethylene glycol)
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Fig. 6 —Large intramuscular extravasation in left sternocleidomastoid
muscle, identified at autopsy as intramuscular hematoma. (case 3; iodized oil
[Lipiodol, Guerbet] and paraffin oil solution)
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Thorax and Abdomen
The perfusion of the right coronary artery in a supine position was in some
cases problematic, most likely due to an incomplete filling of the ventral
parts of the ascending thoracic aorta. This problem was overcome by placing
the cadaver in a prone position because this led to a good filling of the more
ventrally positioned right coronary artery
(Fig. 7). After injection of
the PEG contrast solution, the myocardium of both ventricles displayed
significant enhancement, a finding not observed in the cases with oily
contrast media. A perforation of the right cardiac ventricle by a bullet was
clearly identified by showing the holes in the myocardium and the
extravasation into the pericardial space (Fig.
8A,
8B).
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Fig. 7 —On volume-rendering technique image of coronaries, no
relevant stenoses were diagnosed. Complete depiction of both coronary arteries
was achieved by second scanning in prone position for better filling of more
ventrally situated right coronary ostium. (case 8; iopentol [Imagopaque, GE
Healthcare] and polyethylene glycol)
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Fig. 8A —Gunshot victim. (case 9; iopentol [Imagopaque, GE Healthcare]
and polyethylene glycol Axial CT image (A) and photograph of autopsy
specimen (B) show gunshot to chest with perforation of inferior right
cardiac ventricle (arrow, B) and massive hemorrhagic
pericardial tamponade (asterisks, A). Note extravasation of
contrast media solution in pericardial space. Scale (B) = cm.
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Fig. 8B —Gunshot victim. (case 9; iopentol [Imagopaque, GE Healthcare]
and polyethylene glycol Axial CT image (A) and photograph of autopsy
specimen (B) show gunshot to chest with perforation of inferior right
cardiac ventricle (arrow, B) and massive hemorrhagic
pericardial tamponade (asterisks, A). Note extravasation of
contrast media solution in pericardial space. Scale (B) = cm.
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The antegrade perfusion of the venous system allowed excellent
visualization of the pulmonary arteries via the right atrium and ventricle. We
diagnosed pulmonary embolism (central and paracentral) (Fig.
9A,
9B) as a cause of death with
both contrast media solutions (Table
1). Minor filling defects of the sub-segmental pulmonary arteries
were found in three other cases. Histology proved these to be small postmortem
clots, which were pushed from the right ventricle in the pulmonary
periphery.
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Fig. 9A —Pulmonary embolism. (case 8; iopentol [Imagopaque, GE
Healthcare] and polyethylene glycol) Axial CT image (A) and photograph
of autopsy specimen (B) with frontal view of opened pulmonary trunk
after removal of heart show massive central and peripheral pulmonary embolism
(arrows) with filling defects in pulmonary trunk and lobe arteries of
both lungs. Thrombotic genesis of material was confirmed at autopsy.
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Fig. 9B —Pulmonary embolism. (case 8; iopentol [Imagopaque, GE
Healthcare] and polyethylene glycol) Axial CT image (A) and photograph
of autopsy specimen (B) with frontal view of opened pulmonary trunk
after removal of heart show massive central and peripheral pulmonary embolism
(arrows) with filling defects in pulmonary trunk and lobe arteries of
both lungs. Thrombotic genesis of material was confirmed at autopsy.
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All cases of injections with the oily contrast solution showed
extravasations in the areas with early autolysis (pancreas, gastrointestinal
tract, intra-, and extraluminal) with no autoptic correlate of a lesion in the
organ tissue or the adjacent vasculature. Furthermore, no significant decrease
in enhancement of the vessels between the arterial and venous injections
during the CT examinations was noted. The injection series with the PEG-mixed
water-soluble contrast media showed no uncorrelated extravasations in any
scans. However, there was intensive enhancement of the vascular bed in the
parenchyma of the organs in the upper abdomen and the gastrointestinal wall,
enabling the depiction of parenchymal lesions in these areas (Fig.
10A,
10B). We were able to display
lesions of the abdominal aorta and the inferior vena cava after the injection
with PEG contrast media (Figs.
11A,
11B,
11C and
12A,
12B), with the corresponding
intra- and retroperitoneal extravasates. Even tiny lesions of branches of the
superior mesenteric arteries could be displayed well
(Fig. 13). With the PEG
contrast solution, an intravascular contrast decrease of about 50% in 15
minutes was found and allowed an almost separate imaging of the abdominal
arterial and venous systems (Fig.
14A,
14B).
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Fig. 10A —Gunshot to chest. (case 9; iopentol [Imagopaque, GE
Healthcare] and polyethylene glycol) Sagittal multiplanar reconstruction image
(A) and photograph of autopsy specimen (B) show bullet track
(dashed line, A) through inferior sternum, with final position
of projectile in intervertebral space L1–L2. Penetration of left lobe of
liver with parenchymal extravasation of contrast media solution along
intrahepatic bullet track (arrow, A) and in omental bursa can
also be seen. Note retrosternal gas bubbles. Because of postmortem decreased
lung volume and cadaver lying on back, heart and liver have been shifted
cranially from original bullet track.
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Fig. 10B —Gunshot to chest. (case 9; iopentol [Imagopaque, GE
Healthcare] and polyethylene glycol) Sagittal multiplanar reconstruction image
(A) and photograph of autopsy specimen (B) show bullet track
(dashed line, A) through inferior sternum, with final position
of projectile in intervertebral space L1–L2. Penetration of left lobe of
liver with parenchymal extravasation of contrast media solution along
intrahepatic bullet track (arrow, A) and in omental bursa can
also be seen. Note retrosternal gas bubbles. Because of postmortem decreased
lung volume and cadaver lying on back, heart and liver have been shifted
cranially from original bullet track.
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Fig. 11A —Gunshot to chest. (case 9, iopentol [Imagopaque, GE
Healthcare] and polyethylene glycol) Axial CT image after arterial perfusion
(A), photograph of gross autopsy specimen (B), and histologic
specimen (elastic Van Gieson stain) (C) show laceration of right
lateral wall of abdominal aorta (arrows) with local aortic dissection
and intraperitoneal extravasation (asterisk, A). Note
enhancement of renal cortex. Scale (B) = cm. Magnification (C) =
x 20.
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Fig. 11B —Gunshot to chest. (case 9, iopentol [Imagopaque, GE
Healthcare] and polyethylene glycol) Axial CT image after arterial perfusion
(A), photograph of gross autopsy specimen (B), and histologic
specimen (elastic Van Gieson stain) (C) show laceration of right
lateral wall of abdominal aorta (arrows) with local aortic dissection
and intraperitoneal extravasation (asterisk, A). Note
enhancement of renal cortex. Scale (B) = cm. Magnification (C) =
x 20.
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Fig. 11C —Gunshot to chest. (case 9, iopentol [Imagopaque, GE
Healthcare] and polyethylene glycol) Axial CT image after arterial perfusion
(A), photograph of gross autopsy specimen (B), and histologic
specimen (elastic Van Gieson stain) (C) show laceration of right
lateral wall of abdominal aorta (arrows) with local aortic dissection
and intraperitoneal extravasation (asterisk, A). Note
enhancement of renal cortex. Scale (B) = cm. Magnification (C) =
x 20.
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Fig. 12A —Gunshot to chest. (case 9, iopentol [Imagopaque, GE
Healthcare] and polyethylene glycol) Axial CT image (A) and photograph
of autopsy specimen (B) show laceration of left lateral wall of
inferior vena cava (arrows). Note local and
perihepatic–perisplenic (asterisk, A) extravasation of
contrast media solution.
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Fig. 12B —Gunshot to chest. (case 9, iopentol [Imagopaque, GE
Healthcare] and polyethylene glycol) Axial CT image (A) and photograph
of autopsy specimen (B) show laceration of left lateral wall of
inferior vena cava (arrows). Note local and
perihepatic–perisplenic (asterisk, A) extravasation of
contrast media solution.
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Fig. 13 —Coronal maximum-intensity-projection reconstruction of
superior mesenteric artery shows extravasation around left proximal branch of
vessel. Rupture was caused by massive compression of thorax and upper abdomen.
Note enhancement of pancreatic parenchyma and walls of gastrointestinal tract.
(case 6; iopentol [Imagopaque, GE Healthcare] and polyethylene glycol)
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Fig. 14A —Same case after contrast injection. (case 6; iopentol
[Imagopaque, GE Healthcare] and polyethylene glycol)
Maximum-intensity-projection reconstruction images after arterial (A)
and venous (B) injection of contrast media solution provide detailed
depiction of thoracoabdominal vasculature. Note decreasing arterial
enhancement during interval (15 minutes) between injections, allowing almost
separate imaging of arteries and veins.
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Fig. 14B —Same case after contrast injection. (case 6; iopentol
[Imagopaque, GE Healthcare] and polyethylene glycol)
Maximum-intensity-projection reconstruction images after arterial (A)
and venous (B) injection of contrast media solution provide detailed
depiction of thoracoabdominal vasculature. Note decreasing arterial
enhancement during interval (15 minutes) between injections, allowing almost
separate imaging of arteries and veins.
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Extremities
With both contrast media solutions, the arteries of the upper extremities
showed a sufficient enhancement, even of the phalangeal arteries (Fig.
15A,
15B). The vessels of the thigh
and the lower leg were also excellently depicted. This even allowed for the
detection of peripheral arterial occlusive disease (Fig.
16A,
16B).
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Fig. 15A —Imaging of arm and hand. (case 7; iopentol [Imagopaque, GE
Healthcare] and polyethylene glycol) Volume-rendered technique image of right
brachial arteries after arterial filling provides complete visualization of
radial and ulnar arteries. Osseous structures have been removed by volume
editing.
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Fig. 15B —Imaging of arm and hand. (case 7; iopentol [Imagopaque, GE
Healthcare] and polyethylene glycol) Volume-rendered technique image of right
hand, palmar view, provides visualization of even small phalangeal
arteries.
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Fig. 16A —Imaging of leg and foot. Volume-rendered technique image
shows trifurcation of right popliteal artery, with signs of peripheral
arterial occlusive disease of right leg, mainly seen as lumen irregularities
in right peroneal artery (arrows). (case 7; iopentol [Imagopaque, GE
Healthcare] and polyethylene glycol)
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The retrograde filling of the venous bed of the extremities was
occasionally unsatisfying. Depending on the sufficient functioning of the
venous valves, only a proximal portion of the veins of the limbs filled with
contrast media solution. Subcutaneous and intramuscular hemorrhages were
consistently characterized by contrast extravasations.
Discussion
Both contrast media solutions allowed for postmortem whole-body
angiographies. The most distinct difference of the two solutions is the
enhancement of physiologically well-perfused tissues (cerebral cortex,
myocardium, pancreatic and splenic tissue, renal cortex, and liver) seen with
the PEG contrast solution and the unwanted extravasation through the pancreas
and the intestines with the oily contrast compound. This enhancement
phenomenon may be due to the molecular size of the oily compound, with a
molecular size approximately equal to that of paraffin oil and Lipiodol.
The PEG and water-soluble contrast media solution consists, by contrast, of
a large polymerized part (PEG 200) and an unpolymerized part with smaller
molecular dimensions (Imagopaque). The oily compound, including the contrast
agent, may seep through small vascular leaks in areas of early decomposition
and may therefore give rise to unwanted extravasation. However, PEG, by virtue
of its greater molecule size, will tend to remain in unharmed vessels and
therefore be more decomposition-artifact resistant. The enhancement of
well-vascularized tissues probably arises from a diffusion of the small
molecular hydrophilic contrast media in the interstitial and intracellular
spaces. This mechanism enables the separate visualization of the arterial and
venous system with PEG, but it also raises the need of an instant CT
examination after the injection. The oily compound of paraffin oil and
Lipiodol remains in the greater vessels for a couple of hours, leaving more
time between the injection and scanning. If the contrast media injection is
performed in the CT room, this apparent advantage of the oily solution is
negligible.
In conclusion, postmortem angiography with PEG has clear advantages in
displaying abnormalities of well-vascularized tissues and avoids unwanted
extravasations in the gastrointestinal tract. With this method, whole-body
angiography with visualization of vascular abnormalities is possible. This may
augment clinical and forensic postmortem examinations and, in combination with
imaging-guided specimen sampling for histology and toxicology and whole-body
CT and MRI, serve as a viable compromise to autopsy while ensuring clinical
quality control and forensic assessment. Furthermore, the acquired data can be
reevaluated at any time and is therefore fully reproducible for future
research and counter-expertise.
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Abstract
Introduction
