Elsevier

Legal Medicine

Volume 12, Issue 5, September 2010, Pages 215-222
Legal Medicine

Review Article
Clinical radiology and postmortem imaging (Virtopsy) are not the same: Specific and unspecific postmortem signs

https://doi.org/10.1016/j.legalmed.2010.05.005Get rights and content

Abstract

The aim of this article is to disclose the characteristics of postmortem forensic imaging; give an overview of the several possible findings in postmortem imaging, which are uncommon or new to clinical radiologists; and discuss the possible pitfalls. Unspecific postmortem signs are enlisted and specific signs shall be presented, which are typical for one cause of death.

Unspecific signs. Livor mortis may not only be seen from the outside, but also inside the body in the lungs: in chest CT internal livor mortis appear as ground glass opacity in the dependent lower lobes. The aortic wall is often hyperdense in postmortem CT due to wall contraction and loss of luminal pressure. Gas bubbles are very common postmortem due to systemic gas embolism after major open trauma, artificial respiration or initial decomposition; in particular putrefaction produces gas bubbles globally.

Specific signs. Intracranial bleeding is hyperattenuating both in radiology and in postmortem imaging. Signs of strangulation are hemorrhage in the soft tissue of the neck like skin, subcutaneous tissue, platysma muscle and lymph nodes. The “vanishing” aorta is indicative for exsanguination. Fluid in the airways with mosaic lung densities and emphysema (aquosum) is typical for fresh-water drowning.

Introduction

Medical imaging like computed-tomography (CT) and magnetic resonance imaging (MRI) play a major role in clinical medicine. Without evidence based, accurate diagnostic there is no effective treatment. In all disciplines in medicine, radiology got more and more important over the past decades with the development of new techniques (MRI) and better resolutions (CT). Imaging revolutionized forensic medicine not only for diagnostic reasons but also for documentation, which is even applicable in court.

At the beginning of postmortem imaging in 2000 [1], nobody knew the “normal” appearance of all the organs with the sedimentation effect of the blood, the gas formation during decomposition and the altered body temperature. Furthermore, radiologists nowadays are much more used to contrast enhanced imaging methods than to non-contrast examination like postmortem imaging. Although postmortem contrast enhanced examination techniques with promising results have been recently described by Ross et al. [2], [3], [4] the aim of this article is to describe the differences between radiology and non-contrast postmortem imaging (Virtopsy). All basic postmortem changes that may appear in dead people but are perfectly “normal” in this setting shall be described: over the past years we gained more experience and several unspecific postmortem radiological signs could be established [5], [6], [7], [8], [13], [14], [15]. Also postmortem signs that are specific for a certain cause of death will be described [9], [10], [11], [12], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [5], [28], [29], [30], [31], [32], [33], [34], [35], [36].

Section snippets

Technical aspects of Virtopsy

Virtopsy is a specific method, where deceased persons get a classic forensic autopsy combined with postmortem pre-autoptic multislice-computed-tomography (CT) and optional magnetic resonance imaging (MRI) of the whole body without contrast media application [37]. At the beginning of Virtopsy CT was performed on a GE Lightspeed QX/I unit (General Electric, Milwaukee, WI, USA), today it is done on a Somatom 6 unit (Siemens Medical Solutions, Erlangen, Germany). Axial slices are acquired with a

Loss of cortico-medullary differentiation

For the brain the act of dying is patho-physiologically like suffering a stroke: postmortem hypoxia leads to edema formation which obscures the border between white and grey matter. In CT the difference of attenuation between cortex and medulla of the brain decreases rather fast (Fig. 1). This sign is also known in living patients, but it is not compatible with regular brain function. It is usually seen in brain-death patients.

In MRI the cortico-medullary differentiation remains much longer and

Strangulation

Specific signs for strangulation have been shortly established in imaging [11], [25], [26]. There are some common signs in clinical radiology and in postmortem imaging: hemorrhage into the skin, subcutaneous and intramuscular hemorrhage are common (Fig. 8). The sternocleidomastoid and platysma muscle are frequently affected. Hemorrhagic and edematous lymph nodes are a specific sign of strangulation and occur from the venous congestion like the forensic ophthalmologic petechiae. Forensic

Motion artifacts

This rather specific sign for live occurs only in radiology due to respiration, swallowing or beating of the heart during data acquisition. Therefore the border of the diaphragm and the heart can be blurred or doubled (Fig. 9a). Pulsation-artifacts of the aorta may even simulate a dissection membrane (Fig. 9b). These artifacts can be diminished with proper breathing commands and electrocardiogram triggered scans. Obviously these problems do not exist in Virtopsy. Of course, there is need to

Low contrast

Generally in CT the structures of organs and the pathologies are better visible after contrast administration; therefore, abdominal imaging of the living has the higher potential. But MRI helps a lot in detecting edematous pathologies, because of the water-sensibility of the T2 sequences.

“Vanishing” aorta

After fatal hemorrhage the abdominal vessels behave like the big thoracic arteries and veins. Fatal bleeding empties the blood vessel globally. But death generally leads to a loss of intravascular pressure that

Conclusion

The difference in imaging the living or the dead is sometimes unapparent like in the detection of cranial hemorrhage. Sometimes the lack of contrast in postmortem imaging is so obvious like in aortic imaging, where one has difficulties to find an aortic tear. The lack of contrast in postmortem imaging is compensated by an additional modality: a combined CT and MRI analysis helps to increase the accuracy of forensic imaging. A main aim of this article is to give an overview of the several

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