The radiodensity of cerebrospinal fluid and vitreous humor as indicator of the time since death

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.

Results

Group A showed increasing radiodensity of the CSF and VH over time (r ² CSF, 0.65). PMI overruled the influence of temperature (r = 0.99 and p = 0.000). Groups B and C showed more diversity, with CSF and VH radiodensities below the mean regression line of Group A. The formula of this upper limit indicated the maximum PMI and was correct for >95 % of the cadavers.

Conclusion

The results of group A showed a significant correlation between CSF radiodensity and PMI. The radiodensities in groups B and C were higher than in group A, therefore the maximum PMI can be estimated with the upper 95 % confidence interval of the correlation line of group A.

     

Determination of calcium and magnesium in postmortem human vitreous humor as a test to ascertain the cause and time of death

Summary The concentrations of magnesium and total calcium human vitreous humors obtained postmortem was tested. In the groups of heart disease and asphyxia a correlation between the postmortem interval and calcium or magnesium concentrations was found. There was no correlation between postmortem interval and calcium respectively magnesium in the other causes of death. It seems possible that the analysis of vitreous humor may be useful in both diagnosis and determination of postmortem interval in the cases of heart death and asphyxia.     

When a death apparently associated to sexual assault is instead a natural death due to idiopathic hypereosinophilic syndrome: The importance of gamma-hydroxybutyric acid analysis in vitreous humor

We here report a case involving a 21-year-old female, found dead in a central square of a city in the south of Italy. Initial evidences and circumstances were suggestive of a death associated with a sexual assault. Two peripheral blood and two vitreous humor samples were collected for the purpose of gamma-hydroxybutyric acid (GHB) testing from the dead body at two different post-mortem intervals (PMIs): approximately 2 (t₀) and 36 (t₁) hours. The obtained results showed that, between t₀ and t_1, there was an increase of GHB concentrations in peripheral blood and vitreous humor of 66.3% and 8.1%, respectively.This case was the first evidence of GHB post mortem production in a dead body and not in vitro, showing that vitreous humor is less affected than peripheral blood in GHB post-mortem production.The value detected at t₁ in peripheral blood (53.4 µg/mL) exceeded the proposed cut-off and if interpreted alone would have led to erroneous conclusions. This was not the case of vitreous humor GHB, whose post-mortem increase was minimal and it allowed to exclude a GHB exposure.Only after a broad forensic investigation including a complete autopsy, serological, histological, toxicological and haematology analyses, a diagnosis of idiopathic hypereosinophilic syndrome, a myeloproliferative disorder characterized by persistent eosinophilia associated with damage to multiple organs, was made and the cause of death was due to a pulmonary eosinophilic vasculitis responsible for an acute respiratory failure.     

Post-mortem vitreous ammonium concentrations in estimating the time of death

Summary On a total of 150 specimens of vitreous humor the post-mortem ammonia value was determined by diffusion method. The results established that there existed a regular ammonia increase after a sudden death and that deviating high or low vitreous ammonia values are strongly correlated with the cause of death and with environmental temperature.The ammonia content of the vitreous humor extracted from both eyes at the same and at different post-mortem intervals showed no differences in the concentrations between both specimens sampled at the same moment while an obvious variation in the individual rate of the vitreous ammonia increase is found, especially when hospital cases with antemortem existing disease are concerned.

---

Zusammenfassung Der Ammoniakgehalt der Glaskörperflüssigkeit wurde gemessen an insgesamt 150 Entnahmen mit bekannter Todeszeit nach der Diffusionsmethode. Die Ergebnisse zeigen einen regelmässigen postmortalen Anstieg des Ammoniaks in plötzlichen Todesfällen während abweichend höhere und niedrigere Messzahlen sich eng korreliert verhalten mit der Todesursache und dem Aussentemperatur. Doppelbestimmungen des Ammoniakgehalts im Corpus Vitreum beider Augen zu gleicher und verschiedener Leichenzeit vorgenommen erweisen keine Konzentrationsunterschiede in den zu gleicher Zeit entnommenen Proben aber eine merkbare Schwankung in dem individuellen Anstieg der Ammoniakwerte des Glaskörpers, besonders wenn Hospitalfälle mit vorherigen Krankheiten betroffen sind. Wegen der Beschränkung einer notwendigen Selektion in bezug auf Ursache und Plötzlichkeit eines Sterbens ist die Methodik der Ammoniakbestimmung im Glaskörperinhalt angesichts der mit zunehmender Liegezeit wachsenden individuellen Streuung nur als zusätzliches Hilfsmittel zur Todeszeitschätzung verwendbar.

     

A pilot study to determine the effect of radiographer training on radiostereometric analysis imaging technique

IntroductionProducing x-ray images for radiostereometric analysis (RSA) is a demanding technique. Suboptimal examinations result in a high percentage of exposure repetition. The aim of this pilot study was to use an experiential training approach to sharpen the skills of radiographers in acquiring images of an optimal quality.MethodsA controlled trial using action research strategy was used. The study entailed a two phased approach. Radiographers were purposefully recruited and trained to perform the required investigations. Each phase included 12 examinations of a total knee arthroplasty phantom followed by 10 patient examinations. The quality of all x-ray images performed during the two phases was characterized by measuring the number of visible beads, the center position of the prosthesis (CP) compared to the center of calibration field (CCF). The number of re-exposures used to obtain a usable image during patient examinations was also recorded.ResultsThe radiographers undergoing the training resulted in a significant improvement in the quality of images produced and visualization of the beads. That is, the ability to move the CP on average 36.1 mm closer to the CCF (p < 0.001), the number of visible beads increased by 3.1 (p < 0.001) and radiographers needed 2.1–2.9 exposures less to obtain RSA images of sufficient qualities during patient examinations in phase 2 (p < 0.001).ConclusionThis study illustrates the value of experiential method of teaching and learning with minimal compromise on patient safety but a significant contribution in terms of establishing quality of RSA images.     

Determination of glucose in human vitreous humor

Summary In twenty cases, human vitreous humor glucose concentrations were measured with five different methods in common use. Striking differences in glucose values were obtained by the various analytical procedures. The reasons for these discrepancies remain obscure. Before interpretation of a given vitreous value, therefore, the analytical method employed must be known.

---

Zusammenfassung In Glaskörper-Flüssigkeit wurde die Glucose-Konzentration mit fünf verschiedenen Methoden, die im allgemeinen Gebrauch sind, in zwanzig Fällen bestimmt. Es wurden hierbei erhebliche Differenzen in den Glucose-Werten mit den verschiedenen Analysenmethoden erhalten, wobei die Ursachen für die Diskrepanzen unklar sind. Bei der Beurteilung von Glucose Konzentrationen im Glaskörper muß daher die angewandte Bestimmungsmethode berücksichtigt werden.

     

Study of vitreous potassium correlation with time since death in the postmortem range from 2 to 110 hours using capillary ion analysis

The time-dependent postmortem increase of potassium concentration in the eye fluids has been studied since the 1960s. However, important discrepancies on the reproducibility of the phenomenon have hampered the use of this parameter in real cases. In recent years, a new analytical approach based on capillary ion analysis (CIA) has been reported. In the present work, the correlation between vitreous potassium and postmortem interval (PMI) has been re-evaluated by using CIA in a group of 164 cases with PMIs ranging from 2 to 110 hours. The correlation of the two parameters was described by the following regression equation: y = 0.1733x + 2.3008 (x = PMI; y = K(+) concentration); correlation coefficient = 0.962. The re-calculation of PMIs on the basis of this equation provided calculated PMIs with an average error of 5.54 hours (SD = 4.16). However, the percent PMI calculation error decreased with the increase of PMI, becoming acceptable for practical application above 24 hours since death.     

Prospective study with specific Re-Assessment time points to determine time to recovery following a Sports-Related Concussion in university-aged student-athletes

BackgroundTime to recovery for symptom burden and neurocognition following a Sports-Related Concussion (SRC) has previously been determined by consolidating varying re-assessment time points into a singular point, and has not been established for Vestibular-Ocular-Motor (VOM) function or academic ability.ObjectivesEstablish when recovery of symptom burden, neurocognition, VOM function, and academic ability occurs in university-aged student-athletes.MethodsStudent-athletes completed an assessment battery (Post-Concussion Symptom Scale (PCSS), Immediate Post-Concussion Assessment and Cognitive Test (ImPACT), Vestibular Ocular-Motor Screening (VOMS), Perceived Academic Impairment Tool (PAIT)) during pre-season (n = 140), within 48 hours, 4, 8 and 14 days post-SRC and prior to Return To Play (RTP) and were managed according to the Rugby Football Union’ community pathway (n = 42). Student-athletes were deemed recovered or impaired according to Reliable Change Index’ (RCI) or compared to their individual baseline.ResultsSymptom burden recovers by four days post-SRC on RCI and to baseline by eight days. VOM function and academic ability recovers by 8 days. Some student-athletes demonstrated worse performance at RTP on all tests by RCI and to baseline, except for on VOMS score and near point convergence by RCI change.ConclusionsVariation in individual university-aged student-athletes requires a multi-faceted approach to establish what dysfunctions post-SRC exist and when recovery occurs.     

Application of the Cozart DDS system to postmortem screening of drugs of abuse in vitreous humor

The analysis of drugs of abuse in human specimens is essential in forensic medicine. This study evaluated the use of Cozart DDS for postmortem screening of some drugs of abuse in vitreous humor (VH) prior to forensic autopsies. The Cozart DDS is an on-site drug detection system that has been validated for oral fluid. Seventy-one VH specimens were obtained from cadavers. Causes of death included injury, drug poisoning, natural disorders, and traffic accidents. The samples were tested for cannabis, cocaine, opiate, amphetamine, and methamphetamine. Thirty-three of 71 samples were positive for drugs of abuse (42% for cocaine, 28% for cannabis, 26% for opiates, and 3% for methamphetamine). The positive specimens for opiates and methamphetamine were reexamined by gas chromatography-mass spectrometry (GC-MS); benzoylecgonine (cocaine product) was detected by liquid chromatography-tandem mass spectrometry (LC-MS-MS). All positive results for cocaine or its products and opiates by the Cozart test were confirmed by MS analysis, whereas one positive result for methamphetamine was negative by MS. The Cozart DDS system is generally a useful screening test for VH specimens prior to autopsies, because of its simplicity and rapidness.     

Interpretation of drug concentrations in an alternative matrix: the case of meprobamate in vitreous humor

The use of vitreous humor (VH) as an alternative matrix to blood in the field of forensic toxicology has been described for numerous drugs. Interpretation of drug concentrations measured in VH, as in other matrices, requires statistical analysis of a data set obtained on a significant series. In the present study, two diagnostic tests interpreting postmortem VH concentrations of meprobamate in 117 sets of autopsy data are reported. (1) A VH meprobamate concentration threshold of 28 mg/l was statistically equivalent to that of blood meprobamate concentration threshold of 50 mg/l distinguishing overdose from therapeutic use in blood. The intrinsic qualities of the test were good, with sensitivity of 0.95 and absolute specificity of 1. (2) A novel interpretation tool is proposed, allowing blood concentration range to be evaluated, with a known probability, from VH concentration.     

Decision-making models in the analysis of portal films: a clinical pilot study

Portal films continue to play an important role in the verification of radiotherapy treatment. There is still some discussion, however, as to what action should be taken after a port film has shown a radiation field deviation from the prescribed volume. It was the aim of the present pilot study to investigate the performance of three decision-making models ('Amsterdam', 'Quebec' and 'Newcastle') and an expert panel basing their decision on intuition rather than formal rules after portal film acquisition in a clinical setting. Portal films were acquired on every day during the first week of treatment for five head and neck and five prostate cancer patients (diagnostic phase). If required, the field position was modified according to our normal practice following the recommendation of the expert panel. In order to analyse the results of the models, however, additional port films were taken in the following 3 treatment weeks with the patient moved as required by the different models (intervention phase). The portal films were taken over 4 consecutive days, positioning the patient according to each of the different models on one day each. None of the models diagnosed a field misplacement in the head and neck patients, while the 'Amsterdam' and 'Quebec' models predicted a move in one prostate patient. The 'Newcastle' model, which is based on Hotelling's T2 statistic, proved to be more sensitive and diagnosed a systematic displacement for three prostate patients. The intervention phase confirmed the diagnosis of the model, even if the three portal films taken with the patient position adjusted as required by the model proved to be insufficient to demonstrate an improvement. The 'Newcastle' model does not rely on assumptions about the random movement of patients and requires five portal films before a decision can be reached. This approach lends itself well to incorporation into electronic portal imaging 'packages', where repeated image acquisitions present no logistical difficulty.     

Estimating the time of death with infrared tympanic thermometer: a new prospective study in France

International Journal of Legal Medicine - Very few studies are available on the use of infrared tympanic thermometer to estimate the postmortem interval. The purpose is to observe the decrease of...     

Pharmacokinetics of heroin and its metabolites in vitreous humor and blood in a living pig model

Vitreous humor (VH) is an alternative matrix for drug analysis in forensic toxicology. However, little is known about the distribution of xenobiotics, such as opioids, into VH in living organisms. The aim of this study was to simultaneously measure heroin and metabolite concentrations in blood and VH after injection of heroin in a living pig model. Six pigs were under non-opioid anesthesia during the surgical operation and experiment. Ocular microdialysis was used to acquire dialysate from VH, and a venous catheter was used for blood sampling. Twenty milligrams of heroin was injected intravenously with subsequent sampling of blood and dialysate for 6 h. The samples were analyzed by ultra-performance liquid chromatography–tandem mass spectrometry. Heroin was not detected in VH; 6-monoacetylmorphine (6-MAM) and morphine were first detected in VH after 60 min. The morphine concentration in VH thereafter increased throughout the experimental period. For 6-MAM, C _max was reached after 230 min in VH. In blood, 6-MAM reached C _max after 0.5 min, with a subsequent biphasic elimination phase. The blood and VH 6-MAM concentrations reached equilibrium after 2 h. In blood, morphine reached C _max after 4.3 min, with a subsequent slower elimination than 6-MAM. The blood and VH morphine concentrations were in equilibrium about 6 h after injection of heroin. In conclusion, both 6-MAM and morphine showed slow transport into VH; detection of 6-MAM in VH did not necessarily reflect a recent intake of heroin. Because postmortem changes are expected to be small in VH, these experimental results could assist the interpretation of heroin deaths.     

High variation in hypoxanthine determination after analytical treatment of vitreous humor samples

In the field of legal medicine the correct determination of the time of death is of great importance because an error in calculating the post-mortem interval (PMI) could be crucial in a criminal investigation. The quantification of hypoxanthine (Hx) concentration in the vitreous humor (VH) as a means to estimate PMI is useful when dealing with a recent time interval of death and has several advantages over other biological matrices. However, due to its viscous nature, VH has to be liquefied prior to its analysis, and the different procedures to liquefy it may cause alterations in Hx concentration, and hence in estimation of PMI. The aim of this study was to determine differences in Hx concentration after applying several pre-analytical treatments to different aliquots of the same VH sample. Enzymatic digestion, sonication, centrifugation and heat were the liquefying methods applied to reduce the viscosity of 105 VH samples. Analysis was performed using solid phase extraction and liquid chromatography in tandem with mass spectrometry. Statistically significant differences in the measured Hx concentrations were found between enzymatic digestion and the other three methods analyzed (sonication, centrifugation, and heat). Additionally, high data dispersion was found under heat treatment but was not observed for centrifugation or sonication, where similar and more moderate results were found. We conclude that high variations in Hx determination are observed when enzymatic digestion or heat treatment is used and we therefore recommend sonication or centrifugation to quantify Hx concentration in the VH.     

Integrin receptor imaging of breast cancer: a proof-of-concept study to evaluate 99mTc-NC100692.

The present study was a proof-of-concept study to provide an initial indication of the efficacy and safety of imaging malignant breast tumors using (99m)Tc-NC100692. The agent is a small peptide with high affinity for integrin receptors that are upregulated and expressed preferentially on proliferating endothelial cells. METHODS: Sixteen patients with suggestive mammographic findings and 4 patients with benign lesions were included. The "standard of truth" was based on the histopathologic diagnosis of the recruited patients. All subjects received up to 75 microg of (99m)Tc-NC100692 with an average (99m)Tc activity of 694 MBq (range, 561-747 MBq). Safety endpoints were treatment-emergent adverse events (AEs) and changes in a limited physical examination, electrocardiogram (ECG) recordings, blood biochemistry, hematology, coagulation, vital signs, and urine analysis after administration of (99m)Tc-NC100692 and throughout the 24-h follow-up. Static images and SPECT were acquired between 40 min and 2.5 h after injection of the agent. Two experienced nuclear medicine physicians read the images in a nonblinded fashion. RESULTS: Nineteen of 22 malignant lesions were detected using (99m)Tc-NC100692 scintigraphy. Twenty lesions confirmed as malignant by histopathology were seen on mammography or ultrasound. Two additional lesions were identified from histopathology alone. Safety parameters evaluated through the follow-up period of 2.5 h included clinical laboratory tests, vital signs, and ECG. Five of 20 subjects experienced nonserious AEs, and all AEs were classified as mild. One subject experienced an AE (dysgeusia) possibly related to administration of (99m)Tc-NC100692. This AE was mild and lasted only for a few minutes. No deaths, serious AEs, or withdrawals due to AEs occurred during the study. CONCLUSION: Nineteen of 22 malignant lesions (86%) were clearly detected via scintigraphic imaging after administration of (99m)Tc-NC100692. Overall, the efficacy data in subjects with suspected breast lesions suggest that (99m)Tc-NC100692 scintigraphy may be effective in detecting malignant lesions. The use of (99m)Tc-NC100692 in subjects with breast cancer is safe and well tolerated. Further studies are warranted to assess the clinical potential of (99m)Tc-NC100692.     

Analysis of age-related carbonylation of human vitreous humor proteins as a tool for forensic diagnosis

Age-related changes of protein carbonylation due to oxidative damage in human vitreous humors were analyzed. The vitreous samples were collected from 51 autopsied bodies (male: 27, 13-87 years-old, female: 24, 18-80 years-old) whose postmortem interval was less than 4 days. Total protein carbonyl content was assessed by colorimetry using 2,4-dinitrophenylhydrazine and particular carbonylated proteins were identified by immunostaining of vitreous proteins resolved by SDS-PAGE and MALDI-TOF MS with peptide mass fingerprinting. No significant correlation was found between total protein carbonyl content and biological age. However, two major proteins, albumin and transferrin, were found to be heavily carbonylated in the samples from individuals age 40 or over. Furthermore, an immunostained cluster of proteins at 50-60 kDa was discernible in the samples of aged individuals, and it was revealed to contain alpha enolase, pigment epithelial differentiating factor, type 2 keratin subunit protein, and S-arrestin. The results of this study suggest that some retinal proteins detected in the vitreous humor sample would be markers of age-related oxidative stress and biological age.