The radiodensity of cerebrospinal fluid and vitreous humor as indicator of the time since death
The radiodensity of cerebrospinal fluid and vitreous humor as indicator of the time since death
Desire´e H. J. L. M. Koopmanschap 0 1 2 3 4
Alireza R. Bayat 0 1 2 3 4
Bela Kubat 0 1 2 3 4
Henri M. de Bakker 0 1 2 3 4
Mathias W. M. Prokop 0 1 2 3 4
Willemijn M. Klein 0 1 2 3 4
0 Department of Pathology, Netherlands Forensic Institute , Laan van Ypenburg 6, 2497 GB Den Haag , The Netherlands
1 Department of Radiology and Nuclear Medicine, Radboud University Medical Center , Geert Grooteplein Zuid 25, 6525 GA Nijmegen , The Netherlands
2 & Willemijn M. Klein
3 Department of Radiology, Groene Hart Ziekenhuis , Bleulandweg 10, 2803 HH Gouda , The Netherlands
4 Department of Pathology, Maastricht University Medical Center , P. Debyelaan 25, 6229 HX Maastricht , The Netherlands
Purpose After death, a series of changes occur naturally in the human body in a fairly regular pattern. These postmortem changes are detectable on postmortem CT scans (PMCT) and may be useful in estimating the postmortem interval (PMI). The purpose of our study is to correlate the PMCT radiodensities of the cerebrospinal fluid (CSF) and vitreous humor (VH) to the PMI. Methods Three patient groups were included: group A consisted of 5 donated cadavers, group B, 100 in-hospital deceased patients, and group C, 12 out-of-hospital forensic cadavers. Group A were scanned every hour for a maximum of 36 h postmortem, and the tympanic temperature was measured prior to each scan. Groups B and C were scanned once after death (PMI range 0.2-63.8 h). Radiodensities of the VH and CSF were measured in Hounsfield units. Correlation between density and PMI was determined using linear regression and the influence of temperature was assessed by a multivariate regression model. Results from group A were validated in groups B and C.
Postmortem computed tomography; Radiodensity; Cerebrospinal fluid; Vitreous humor; Postmortem interval
Introduction
Estimating the time of death is an important part of
forensic pathology with the postmortem interval (PMI)
being defined as the period of time that has elapsed since a
person has died. In a medico-legal investigation of death,
an accurate estimation of the PMI can be of great
importance. It may aid in identification of the victim and, in cases
of a violent death, limit the number of suspects and help to
validate or reject an alibi and verify witnesses’ statements
[
1
]. Also, in the postmortem diagnostic follow-up in a
clinical setting, knowledge about the PMI is pertinent in
being able to differentiate between normal postmortem
changes and pre- or peri-mortem pathology [
2–4
].
Several techniques can be used if the time of death is
unknown. In the immediate hours after death, medical
examiners and pathologists usually ascertain the PMI
utilizing early postmortem changes such as algor mortis (the
decrease in body temperature after death), livor mortis
(postmortem lividity or hypostasis), and rigor mortis
(chemical change in muscle tissue that causes stiffening)
[
5
]. These traditional methods have been accompanied by
numerous tests or rules-of-thumb such as the drop in body
temperature, which is used in the Henssge nomogram in
combination with body weight and clothing, resulting in a
more precise estimation of PMI [
5, 6
]. Biochemical
measurements such as creatine levels in cerebrospinal fluid
(CSF) and vitreous humor (VH) have been investigated, as
well as CSF pleocytosis and trace amines [
7–11
]. These
markers show a good correlation to the PMI, however, the
wide range of estimated times of death makes them less
accurate than the traditional triad of algor, livor, and rigor
mortis.
For around a decade, postmortem computed tomography
(PMCT) and postmortem magnetic resonance imaging
(PMMRI) have been introduced into clinical and forensic
postmortem investigations, to visualize disease and cause
of death and to serve as a virtual guide for autopsy [
12, 13
].
It is interesting to test the possibilities of PMCT in aiding
the estimation of time of death as these digital scans may
contain more information than just morphology. The
vitreous humor and cerebrospinal fluid may show the least
transformation in the postmortem body, as these are
relatively closed compartments, normally without an open
access to the exterior and usually devoid of bacteria. The
purpose of our study is to correlate the PMCT
radiodensities of the CSF and VH to the PMI.
Materials and methods
Study population
The correlation between PMI and radiodensities of CSF
and VH was determined in 3 distinct groups of cadavers,
with Group A as the standard and Groups B and C
validation groups. In all groups PMCT included head, cervical
spine and a thoracic-abdominal series. For this study
cadavers were scanned in a natural, supine position with
arms next to or on the torso, using the scan parameters as
shown in Table 1. No intravascular contrast agent was
administered, images were ordered caudal to cranial and a
soft filter was applied f (...truncated)