Postmortem contrast-enhanced computed tomography via direct large-vessel puncture.

The aim of this study was to assess the usefulness of postmortem contrast-enhanced CT (PMeCT) performed via direct large-vessel puncture when routine postmortem CT suggests a vascular lesion as the cause of death. PMeCT was performed in 9 cases (4 male, 5 female) with a mean age of 76 years (range 52-92) at the time of death. The mean time elapsed since death was 29.1 h (12.0-72.0). The location of the target vessel for puncture was determined based on the CT table position and a grid placed on the body surface. An 18-G spinal needle was advanced to the puncture site, and the needle tip was confirmed to have reached the intended blood vessel. Using negative pressure with a 20-ml syringe, the needle tip was advanced until reverse bleeding was confirmed. Diluted contrast medium was injected slowly to ensure its dispersion within the blood vessels. Following confirmation of no extravasation, additional doses of diluted contrast agent were injected in 3-4 divided doses, with CT scans obtained at each step to track the distribution of contrast agent over time. PMeCT was successful in all cases, revealing cardiac tamponade in 7 (ascending aortic dissection, n = 6; cardiac rupture, n = 1), thoracic aortic aneurysm rupture, n = 1, and iliac artery aneurysm rupture, n = 1. There were no cases of procedure-related extravasation (pseudo-lesions). When postmortem CT reveals pericardial hematoma or bleeding in the thoracic or abdominal cavity, PMeCT can identify the source of bleeding.

Objective evaluation of changes in serum transmittance over time using a portable color digitizer.

Forensic pathologists empirically understand that postmortem changes can decrease serum transparency and change its color. Such changes are potential indicators for estimating postmortem intervals; however, reports on color changes focusing on postmortem changes in serum are scarce. To elucidate the effect of postmortem intervals on serum levels, we quantitatively evaluated and investigated the relationship between serum color and time using venous blood samples obtained from three healthy male volunteers. The serum samples were separated at 0 (1 h), 1, 2, 3, 4, 7, 10, 16, 21, and 28 days of storage. Serum transmittance and color were measured using a portable color digitizer and a custom-made measurement tool, respectively. Additionally, serum sodium (Na) and potassium (K) concentrations were measured. Serum transmittance showed a logistic curve-like decrease from 0.652 ± 0.016 (0 days) to 0.101 ± 0.014 (28 days) over time. The color changed from greenish yellow (dominant wavelength: 574.4 ± 0.63 nm) to reddish orange (603.97 ± 1.31 nm). Serum Na concentration decreased, whereas serum K concentration increased along the logistic curve. Strong (0.89, p < 0.001) and inverse correlations (-0.93, p < 0.001) were observed between the serum transmittance decrease and the Na concentration decrease and the K concentration increase, respectively. Serum transmittance decreased over time, indicating a transition from bright to dark. Moreover, a strong correlation was observed between serum transmittance and electrolytes, indicating a relationship between time course, serum transmittance, and electrolytes. These findings may contribute to the estimation of postmortem intervals in the future.

Postmortem kinetic CT of the cervical spine and an objective index for diagnosing anterior disc space widening: A retrospective utility analysis.

Postmortem CT has limitations in identifying cervical spine injuries. Injuries at the level of the intervertebral disc (anterior disc space widening), such as rupture of the anterior longitudinal ligament or intervertebral disc, may be difficult to distinguish from normal images depending on the imaging position. We performed postmortem kinetic CT of the cervical spine in the extended position in addition to CT in the neutral position. The difference in intervertebral angles between the neutral and extended positions was defined as the intervertebral range of motion (ROM), and the utility of postmortem kinetic CT of the cervical spine for the diagnosis of anterior disc space widening and its objective index were examined based on the intervertebral ROM. Of 120 cases, 14 had anterior disc space widening: 11 had one lesion and 3 had two lesions. The intervertebral ROM for the 17 lesions was 11.85° ± 5.25° and that for the normal vertebrae was 3.78° ± 2.81°, with a significant difference between the two. ROC analysis of the intervertebral ROM between vertebrae with anterior disc space widening and the normal vertebral spaces showed an AUC of 0.903 (95 % confidence interval 0.803-1) and a cutoff value of 8.61° (sensitivity 0.96, specificity 0.82). Postmortem kinetic CT of the cervical spine revealed that the intervertebral ROM of the anterior disc space widening was increased, which facilitated identification of the injury. An intervertebral ROM that exceeds 8.61° facilitates a diagnosis of anterior disc space widening.

Objective evaluation of chest findings in infants by postmortem computed tomography.

PURPOSE: The purpose of this study was to review the findings of computed tomography (CT) performed early postmortem on infants and to clarify the postmortem CT lung findings that occur in the absence of abnormal histopathological findings. MATERIALS AND METHODS: From July 2016 to March 2022, 72 infants were autopsied with postmortem CT (41 boys 31 girls, aged 0-36 (mean 8.2) months). Autopsy and postmortem CT lung findings were compared with the causes of death identified by the autopsies, namely sudden infant death syndrome (n = 37), acute circulatory system disease (18), drowning (7), asphyxia (5), and dehydration/undernutrition (5). RESULTS: The %aerated lung volume (-700 HU or less) ranged from 0 % to 33 % (mean 1.5 %, median 0 %), being <1 % in 61 cases (84.7 %) and >3 % in 3/5 (60 %) of the dehydration/undernutrition group. The dehydration/undernutrition group showed significant preservation of lung field air content compared with the other causes of death groups (p < 0.05). Receiver characteristic curve analysis showed a cut off value of 0.8 % and area under the curve of 0.88806. The drowning group had significantly greater pleural cavity fluid retention than the other causes of death groups (p < 0.05). No correlation was found between postmortem interval and pleural cavity fluid retention. However, resuscitation time and pleural cavity fluid retention were correlated. CONCLUSION: Evaluation of CT values on postmortem lung fields of infants usually reveals a marked decrease in air content. When air content exceeds 0.8% on infant postmortem CT, dehydration/undernutrition should be considered in the differential diagnosis.