Nicole Schwendener

Rib fractures at postmortem computed tomography (PMCT) validated against the autopsy

To evaluate the sensitivity of postmortem computed tomography (PMCT) in rib fracture detection validated against autopsy. Fifty-one forensic cases underwent a postmortem CT prior to forensic autopsy. Two image readers (radiologist and forensic pathologist) assessed high resolution CT data sets for rib fractures. Correct recognition rates (CRR), sensitivity and specificity values were calculated over all observations as well as individually for every rib and region. Additionally, for partial rib fractures the sensitivity of autopsy was calculated vice versa. 3876 entries in each study protocol (autopsy, PMCT radiologist and PMCT forensic pathologist) were investigated. A total of 690 fractures (autopsy), 491 (PMCT and radiologist) and 559 (PMCT and forensic pathologist) were detected. The CRR was 0.85. Sensitivity and specificity of PMCT for rib fracture detection were 0.63 (0.58 radiologist, 0.68 forensic pathologist) and 0.97 (both readers 0.97), respectively. Low CRR and sensitivity values were obtained for antero-lateral fractures. Partial rib fractures were better detected by PMCT. PMCT has a rather low sensitivity for rib fracture detection when validated against autopsy and indicates that clinical CT may also demonstrate a reasonable number of false negatives. Partial rib fractures often remain undetected at autopsy.

Coronary thrombus and peracute myocardial infarction visualized by unenhanced postmortem MRI prior to autopsy

Sudden cardiac deaths are common within the community. They also constitute a substantial part of daily pathologic and forensic case work. However, macroscopic myocardial findings indicating acute ischemia are often absent. Then, diagnosis is based on coronary status in combination with indirect signs of acute cardiac failure. We present a case of sudden cardiac death where diagnosis was based on cardiac postmortem magnetic resonance imaging (pmMRI) findings already prior to autopsy: the hearts anterior basal ventricular septum showed hypointensities in T2-weighted images that raised suspicion of peracute ischemia. The lumen of the left anterior descending artery (LAD) exhibited a lack of otherwise discernible postmortem sedimentation of cellular blood components. Instead of a sharp border between serum and erythrocytes a homogeneous signal was seen within the narrowed lumen of the beginning LAD over a length of 1cm. Based on this, a thrombotic occlusion was assumed. Subsequent autopsy confirmed peracute septal myocardial ischemia secondary to a thrombotic occlusion of the LAD as concluded from the pmMRI.

Pulmonary thrombembolism as cause of death on unenhanced postmortem 3T MRI

ObjectivesTo investigate unenhanced postmortem 3-T MR imaging (pmMRI) for the detection of pulmonary thrombembolism (PTE) as cause of death.MethodsIn eight forensic cases dying from a possible cardiac cause but with homogeneous myocardium at cardiac pmMRI, additional T2w imaging of the pulmonary artery was performed before forensic autopsy. Imaging was carried out on a 3-T MR system in the axial and main pulmonary artery adapted oblique orientation in situ. In three cases axial T2w pmMRI of the lower legs was added. Validation of imaging findings was performed during forensic autopsy.ResultsAll eight cases showed homogeneous material of intermediate signal intensity within the main pulmonary artery and/or pulmonary artery branches. Autopsy confirmed the MR findings as pulmonary artery thrombembolism. At lower leg imaging unilateral dilated veins and subcutaneous oedema with or without homogeneous material of intermediate signal intensity within the popliteal vein were found.ConclusionsUnenhanced pmMRI demonstrates pulmonary thrombembolism in situ. PmMR may serve as an alternative to clinical autopsy, especially when consent cannot be obtained.Key Points• Postmortem MRI (pmMRI) provides an alternative to clinical autopsy• Fatal pulmonary thrombembolism (PTE) can now be diagnosed using postmortem MRI (pmMRI).• Special attention has to be drawn to the differentiation of postmortem clots.

New evidence for old lore – Urinary bladder distension on post-mortem computed tomography is related to intoxication ☆

INTRODUCTION Distension of the urinary bladder is reported to be a sign of intoxication at autopsy. The purpose of this study was to compare radiologically calculated urinary bladder volume (UBV) to autopsy measurements of UBV, and to investigate the relationship between intoxication and calculated UBV. MATERIALS AND METHODS Autopsy reports, toxicology reports and post-mortem CTs of 332 adult human cadavers were retrospectively analyzed, 259 cases were included in the final population. Spearmans rho test was used to compare calculated UBV to autopsy measurements. Significance levels for UBV in relation to toxicology results were investigated with the Mann-Whitney test. Spearmans rho test was also used to correlate the widest left-right bladder diameter on axial images to calculated UBV. Both calculated UBV and axial diameters were subjected to receiver operating characteristics curve analysis. Sensitivity and specificity were calculated for individual cutoff values. RESULTS There is a strong correlation and high consistency (r=0.92, p<0.001) between the measured and calculated UBV. Positive toxicology results strongly correlate with calculated UBV (p<0.001). Additionally, there is a strong correlation between calculated UBV and axial urinary bladder diameter (p<0.001). UBV of 182 ml and >330 ml indicate positive toxicology results with a sensitivity/specificity of 40%/87% and 25%/97% respectively. Axial urinary bladder diameter of 8.5 cm and >10 cm indicate positive toxicology results with a sensitivity/specificity of 36%/85% and 16%/95% respectively. CONCLUSIONS Radiologically calculated UBV accurately represents the autoptically measured UBV. The occurrence of urinary bladder distension on post-mortem imaging should raise suspicion of intoxication.

Detection and differentiation of early acute and following age stages of myocardial infarction with quantitative post-mortem cardiac 1.5 T MR

Recently, quantitative MR sequences have started being used in post-mortem imaging. The goal of the present study was to evaluate if early acute and following age stages of myocardial infarction can be detected and discerned by quantitative 1.5T post-mortem cardiac magnetic resonance (PMCMR) based on quantitative T1, T2 and PD values. In 80 deceased individuals (25 female, 55 male), a cardiac MR quantification sequence was performed prior to cardiac dissection at autopsy in a prospective study. Focal myocardial signal alterations detected in synthetically generated MR images were MR quantified for their T1, T2 and PD values. The locations of signal alteration measurements in PMCMR were targeted at autopsy heart dissection and cardiac tissue specimens were taken for histologic examinations. Quantified signal alterations in PMCMR were correlated to their according histologic age stage of myocardial infarction. In PMCMR seventy-three focal myocardial signal alterations were detected in 49 of 80 investigated hearts. These signal alterations were diagnosed histologically as early acute (n=39), acute (n=14), subacute (n=10) and chronic (n=10) age stages of myocardial infarction. Statistical analysis revealed that based on their quantitative T1, T2 and PD values, a significant difference between all defined age groups of myocardial infarction can be determined. It can be concluded that quantitative 1.5T PMCMR quantification based on quantitative T1, T2 and PD values is feasible for characterization and differentiation of early acute and following age stages of myocardial infarction.

Type II DeBakey dissection with complete aortic rupture visualized by unenhanced postmortem imaging

We present postmortem computed tomography (pmCT) as well as postmortem magnetic resonance (pmMR) imaging findings in a case of type II DeBakey aortic dissection with a complete rupture of the ascending aorta compared to the findings obtained at forensic autopsy. PmCT only allowed a presumptive diagnosis of aortic dissection based on an anterior mediastinal enlargement. However, at pmMR the dissection including the aortic rupture was clearly visible. Visualization was realized in an unenhanced manner without the need for postmortem angiography.

Post-mortem 1.5T MR quantification of regular anatomical brain structures

Recently, post-mortem MR quantification has been introduced to the field of post-mortem magnetic resonance imaging. By usage of a particular MR quantification sequence, T1 and T2 relaxation times and proton density (PD) of tissues and organs can be quantified simultaneously. The aim of the present basic research study was to assess the quantitative T1, T2, and PD values of regular anatomical brain structures for a 1.5T application and to correlate the assessed values with corpse temperatures. In a prospective study, 30 forensic cases were MR-scanned with a quantification sequence prior to autopsy. Body temperature was assessed during MR scans. In synthetically calculated T1, T2, and PD-weighted images, quantitative T1, T2 (both in ms) and PD (in %) values of anatomical structures of cerebrum (Group 1: frontal gray matter, frontal white matter, thalamus, internal capsule, caudate nucleus, putamen, and globus pallidus) and brainstem/cerebellum (Group 2: cerebral crus, substantia nigra, red nucleus, pons, cerebellar hemisphere, and superior cerebellar peduncle) were assessed. The investigated brain structures of cerebrum and brainstem/cerebellum could be characterized and differentiated based on a combination of their quantitative T1, T2, and PD values. MANOVA testing verified significant differences between the investigated anatomical brain structures among each other in Group 1 and Group 2 based on their quantitative values. Temperature dependence was observed mainly for T1 values, which were slightly increasing with rising temperature in the investigated brain structures in both groups. The results provide a base for future computer-aided diagnosis of brain pathologies and lesions in post-mortem magnetic resonance imaging.

When the prey gets too big: an uncommon road accident involving a motorcyclist, a car and a bird

We present the postmortem findings of a fatal road accident involving a motorcyclist, a car, and a common buzzard. Both the motorcyclist and the bird died on the scene of the accident and were examined by postmortem full-body CT and autopsy. In addition, a facial injury of the motorcyclist was compared with the dimensions of the buzzard’s beak and claws by 3D scan technologies. Blood splatters collected on the bird’s beak, feet, and tail were examined by DNA analysis. The overall findings suggested a collision of a common buzzard with a motorcyclist in full speed, causing the motorcyclist to lose control of his vehicle and crash with an approaching car on the oncoming lane.

Rigor mortis at the myocardium investigated by post-mortem magnetic resonance imaging.

INTRODUCTION Post-mortem cardiac MR exams present with different contraction appearances of the left ventricle in cardiac short axis images. It was hypothesized that the grade of post-mortem contraction may be related to the post-mortem interval (PMI) or cause of death and a phenomenon caused by internal rigor mortis that may give further insights in the circumstances of death. METHOD AND MATERIALS The cardiac contraction grade was investigated in 71 post-mortem cardiac MR exams (mean age at death 52 y, range 12-89 y; 48 males, 23 females). In cardiac short axis images the left ventricular lumen volume as well as the left ventricular myocardial volume were assessed by manual segmentation. The quotient of both (LVQ) represents the grade of myocardial contraction. LVQ was correlated to the PMI, sex, age, cardiac weight, body mass and height, cause of death and pericardial tamponade when present. In cardiac causes of death a separate correlation was investigated for acute myocardial infarction cases and arrhythmic deaths. RESULTS LVQ values ranged from 1.99 (maximum dilatation) to 42.91 (maximum contraction) with a mean of 15.13. LVQ decreased slightly with increasing PMI, however without significant correlation. Pericardial tamponade positively correlated with higher LVQ values. Variables such as sex, age, body mass and height, cardiac weight and cause of death did not correlate with LVQ values. There was no difference in LVQ values for myocardial infarction without tamponade and arrhythmic deaths. CONCLUSION Based on the observation in our investigated cases, the phenomenon of post-mortem myocardial contraction cannot be explained by the influence of the investigated variables, except for pericardial tamponade cases. Further research addressing post-mortem myocardial contraction has to focus on other, less obvious factors, which may influence the early post-mortem phase too.

Post-mortem CT and MR brain imaging of putrefied corpses

IntroductionPutrefaction of the brain is a challenge to a forensic pathologist because it may lead to considerable organ alterations and restrict documenting reliable autopsy findings.ObjectivesThis study aims to present a new and systematic evaluation of possible benefits of post-mortem MR Neuroimaging (1.5 Tesla, sequences: T1w, T2w) in putrefied corpses in comparison to PMCT and autopsy.MethodsA post-mortem MRI brain examination was conducted on 35 adult, putrefied corpses after performing a whole body CT scan prior to a forensic autopsy. Imaging data and autopsy findings were compared with regard to brain symmetry, gray and white matter junction, ventricular system, basal ganglia, cerebellum, brain stem, and possible pathological findings.ResultsAt autopsy, a reliable assessment of the anatomical brain structures was often restricted. MR imaging offered an assessment of the anatomical brain structures, even at advanced stages of putrefaction. In two cases, MR imaging revealed pathological findings that were detectable neither by CT scans nor at autopsy.ConclusionsPost-mortem MR imaging of putrefied brains offers the possibility to assess brain morphology, even if the brain is liquefied. Post-mortem MR imaging of the brain should be considered if the assessment of a putrefied brain is crucial to the evaluation of a forensic autopsy case.