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Imaging features of the lung in postmortem computed tomography (CT) scans have been reported in drowning cases. However, it is difficult for forensic pathologists with limited experience to distinguish subtle differences in CT images. In this study, artificial intelligence (AI) with deep learning capability was used to diagnose drowning in postmortem CT images, and its performance was evaluated. The samples consisted of high-resolution CT images of the chest of 153 drowned and 160 non-drowned bodies captured by an 8- or 64-row multislice CT system. The images were captured with an image slice thickness of 1.0 mm and spacing of 30 mm, and 28 images were typically captured. A modified AlexNet was used as the AI architecture. The output result was the drowning probability for each component image. To evaluate the performance of the proposed model, the area under the receiver operating characteristic curve (AUC) was analyzed, and the AUC value of 0.95 was obtained. This indicates that the proposed AI architecture is a useful and powerful complementary testing approach for diagnosing drowning in postmortem CT images. Notably, the accuracy was 81% (62/77) for cases in which resuscitation was performed, and 92% (216/236) for cases in which resuscitation was not attempted. Therefore, the proposed AI method should not be used to diagnose the cause of death when aggressive cardiopulmonary resuscitation was performed. Additionally, because honeycomb lungs are likely to exhibit different morphologies, emphysema cases should also be treated with caution when the proposed AI method is used to diagnose drowning.

It is challenging to diagnose drowning in autopsy even with the help of post-mortem multi-slice computed tomography (MSCT) due to the complex pathophysiology and the shortage of forensic specialists equipped with radiology knowledge. Therefore, a computer-aided diagnosis (CAD) system was developed to help with diagnosis. Most deep learning-based CAD systems only utilize 2D information, which is proper for 2D data such as chest X-ray images. However, 3D information should also be considered for 3D data like CT. Conventional 3D methods require a huge amount of data and computational cost when using 3D methods. In this paper, we proposed a 2.5D method that converts 3D data into 2D images to train 2D deep learning models for drowning diagnosis. The key point of this 2.5D method is that it uses a subset to represent the whole case, covering this case as much as possible while avoiding other repetitive information. To evaluate the effectiveness of the proposed method, conventional 2D, previous 2.5D, and 3D deep learning-based methods were tested using an MSCT dataset obtained from Tohoku university. Then, to provide explainable diagnosis results, a visualization method called Gradient-weighted Class Activation Mapping was employed to visualize features relevant to drowning in CT images. Results on drowning diagnosis showed that our proposed method achieved the best performance compared to other 2D, 2.5D, and 3D methods. The visual assessment also demonstrated that our method could find the saliency regions corresponding to drowning.

To classify the types of hyperdense areas in the heart cavities on post-mortem CT (PMCT) and compare them according to the presence of blood clots in the heart cavities at forensic autopsy. One hundred and twelve cases with CT images taken before forensic autopsy were evaluated. The presence and shape of hyperdense areas in the right or left heart cavities were retrospectively evaluated on PMCT images and were classified into four types (block-like, cast-like, fluid level-like, and unclear). The presence of blood clots was confirmed when there were clots in the heart cavities at forensic autopsy. Of the 112 cases, 57 exhibited blood clots in the heart cavities at forensic autopsy. The hyperdense areas in the right heart cavities on PMCT in 57 cases exhibiting blood clots at forensic autopsy were classified as follows: block-like, 32; fluid level-like, 4; cast-like, 17; and unclear, 4. The sensitivity of block-like and cast-like hyperdense areas in the right heart cavities on PMCT for the presence of clots in the heart cavities at forensic autopsy was 86% (95% confidence interval [CI]: 74–94%); the corresponding specificity, PPV, and NPV were 95% (95% CI: 85–99%), 94% (95% CI: 84–99%), and 87% (95% CI: 75–94%), respectively. Block-like and cast-like hyperdense areas in the right heart cavities on PMCT predicted the presence of intracardiac blood clots at forensic autopsy. • Clinical radiologists likely have no experience of interpreting findings of blood clots on post-mortem CT (PMCT). • The appearance of blood clots on PMCT provides important clues for diagnosing the cause and process of death. • The shapes of the hyperdense areas in the heart cavities were classified into four types, and two of these types could be used to predict the presence of blood clots in the heart cavities at forensic autopsy.

The liver is an organ that is frequently injured by blunt trauma. In clinical medicine, contrast-enhanced computed tomography (CT) is useful for diagnosing liver damage. However, detection of liver injury is difficult with postmortem CT (PMCT) that does not use contrast media. This study aims to identify findings that are useful for diagnosing liver injury with PMCT. This study included 97 high-energy trauma cases that underwent both PMCT without contrast and forensic autopsy between July 2009 and November 2020. PMCT findings in and around the liver in cases of liver injury were collected. The diagnostic accuracy of each finding was calculated. Of 97 cases, 62 had liver injury on autopsy. PMCT detected hepatic surface gas in 31 cases, intrahepatic focal gas in 19 cases, high-density fluid accumulation around the liver in 12 cases, and fracture of a right lower (9th-12th) rib in 48 cases. Abnormal PMCT findings in and around the liver had insufficient diagnostic sensitivity, ranging from 19.4% to 38.7%. By contrast, the finding of a right lower rib fracture was more sensitive for suspected liver injury. Our results indicate that abdominal liver findings (hepatic surface gas, intrahepatic focal gas, and high-density fluid accumulation around the liver) are of limited utility for the diagnosis of liver injury, whereas a right lower rib fracture is a useful indirect finding.

Co1-xMgxFe2O4 (x=0.0, 0.2, 0.4, 0.6, 0.8, 1.0) nanoparticles embedded in amorphous SiO2 with particle sizes of approximately 4.5 nm were prepared using an original wet chemical method. We performed spin-echo magnetic resonance imaging measurements for Co1-xMgxFe2O4 nanoparticles using a 0.3-T MRI system. The particles exhibited a significant T2 shortening effect compared with that of agarose, depending on the composition. All particles exhibited effective relaxivity, R2, and a significant contrast was observed in the phantom image. Furthermore, thiol group was modified to enable particles to bind specifically to maleimide proteins. These particles are expected to be potential theranostic agents.

Magnetic nanoparticles have drawn attention recently due to their interesting nanoscopic features and potential applications. Various kinds of ferrite nanoparticles with diameters between 3 and 34 nm encapsulated by amorphous SiO2 were functionalized and examined for biomedical applications. From dc and ac magnetic susceptibility measurements, it was found that these particles followed the Neel relaxation system. Co–Zn ferrite (Co0.8Zn0.2Fe2O4) nanoparticles were prepared and the increase in temperature in the ac field was estimated for hyperthermia treatment. In vitro experiments using cultured human breast cancer cells were carried out, and a dramatic hyperthermia effect was observed. As one of the diagnostic methods, magnetic resonance (MR) measurements were performed for CoFe2O4 nanoparticles, and the samples were also evaluated as potential contrast media for MR imaging.

Purpose This phantom study aimed to determine the optimal acquisition window size for phase-based respiratory gating in silicon photomultiplier (SiPM)-based fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and its acquisition time in respiratory-gated imaging with the optimal window size. Methods Images of a moving NEMA IEC Body Phantom SetTM with hot spheres were acquired. First, the tumor volume and the maximum standardized uptake value (SUVmax) of images reconstructed using a different window size were evaluated to define the optimal window size. Second, the quality of the images reconstructed using the optimal window size and different acquisition times was evaluated using the detectability score of the 10-mm hot sphere and physical indices. Results The volume and the SUVmax of the 10-mm hot sphere were improved when the window size was narrow, and there were no significant differences among images reconstructed using a window size narrower than 20%. To reconstruct an image using the 20% window size, an acquisition time of 5 min was required to visualize the 10-mm hot sphere. Conclusions The optimal window size for phase-based respiratory gating is 20%. Further, an acquisition time of 5 min should be taken for respiratory-gated imaging with the 20% window size on SiPM-based FDG-PET/CT.

Feasibility of computer-aided diagnosis (CAD) systems has been demonstrated in the field of medical image diagnosis. Especially, deep learning based CAD systems showed high performance thanks to its capability of image recognition. However, there is no CAD system developed for post-mortem imaging diagnosis and thus it is still unclear if the CAD system is effective for this purpose. Particulally, the drowning diagnosis is one of the most difficult tasks in the field of forensic medicine because findings of the post-mortem image diagnosis are not specific. To address this issue, we develop a CAD system consisting of a deep convolution neural network (DCNN) to classify post-mortem lung computed tomography (CT) images into two categories of drowning and non-drowning cases. The DCNN was trained by means of transfer learning and performance evaluation was conducted by 10-fold cross validation using 140 drowning cases and 140 non-drowning cases of the CT images. The area under the receiver operating characteristic curve (AUC-ROC) for the DCNN was achieved 0.88 in average. This high performance clearly demonstrated that the proposed DCNN based CAD system has a potential for post-mortem image diagnosis of drowning.

Using a car-driving simulator created based on the open source engine---TORCS---we investigate human behavior in car-driving within the car-following setup. Five subjects with different skill of driving were involved in these experiments. Here we present the results of experiments comparing two particular versions of car-following setup; within one the lead car speed was fixed, within the other it changed in a certain irregular way. The latter setup was implemented for three different time scales of speed change representing "fast," "intermediate," and "slow" speed variations. In the case of "fast" speed variations a subject just cannot drive the car such that its speed and the lead car speed vary in time synchronically. In the case of "slow" speed variations it is an easy task. The histograms of the headway, velocity, acceleration, jerk, and the time derivative of pedal position (the main control parameter) constructed based on the collected data are compared. Previously we have demonstrated that driver actions should be categorized as human intermittent control. Based on the presented results we draw the conclusion that this type of driver actions is not sensitive to the uncertainty in the lead car motion.

Objectives Gas is a common finding in cervical intervertebral separation. However, intervertebral gas is also found in many decedents without intervertebral separation. Here, we quantified intervertebral gas and examined its value in the diagnosis of cervical intervertebral separation. Methods We retrospectively reviewed data from 1118 decedents who underwent post-mortem computed tomography (CT) and autopsy from May 2011 to July 2016 and selected those with cervical intervertebral gas with or without intervertebral separation. These data comprised 56 cervical intervertebral spaces with gas [intervertebral separation in 19 (33.9%)] in 43 subjects [intervertebral separation in 17 (39.5%)]. We categorised the decedents according to gas volume, position, and shape and determined the significance of the differences between the decedents with and without separation. Results The gas volume did not differ significantly between decedents with and without separation (p = 0.063). However, there were significant differences in the gas position between decedents with and without separation. In the sagittal plane: gas was seen in the “centred” position in the ventral-to-dorsal direction in more decedents without separation than in those with separation (p = 0.018). Gas was seen in the ventral-to-dorsal positions in more decedents with separation than in those without separation (p = 0.049). In the cranio-caudal direction, gas in the upper position was more common in decedents with separation than in those without separation in the sagittal plane (p = 0.03). In the coronal plane: gas was seen in the upper position more frequently in decedents with separation in the cranio-caudal direction than in those without separation (p = 0.001). A significant difference in gas shape was observed only in the coronal plane (p = 0.024); irregular gas was associated with decedents without separation. Conclusion Gas in the ventral-to-dorsal and upper positions in the sagittal plane and in the upper position in the coronal plane was rather indicative of cervical intervertebral separation. An irregular gas shape in the coronal plane was indicative of degenerative changes.

Objectives The presence of an intervertebral separation indicates vertebral ligamentous injuries, and it is occasionally associated with fatal spinal cord injuries. However, it is often difficult to identify the separation using post-mortem computed tomography (CT). This study retrospectively evaluated the correlation between the post-mortem CT findings and autopsy results of cervical intervertebral separation. Materials and methods Forty-two subjects (8 females and 34 males) with cervical intervertebral separation were evaluated. The average age was 67 (range, 29–88) years. A radiologist retrospectively reviewed the cervical spines on axial, sagittal, and coronal CT images and determined whether intervertebral separations could be detected. The radiologist also classified the CT findings in cases with detectable separations. Results Of the 57 cervical intervertebral separations, 39 were detectable on the CT images. The CT findings were grouped into the following six categories: intervertebral gas (n = 19; 40.4%); forward intervertebral widening (n = 10; 21.3%); backward intervertebral widening (n = 1; 2.1%); anteroposterior misalignment (n = 6; 12.8%); spur fracture (n = 7; 14.9%); and hematoma in front of a vertebral body (n = 4; 8.5%). The sensitivity and specificity of intervertebral gas in the diagnosis of cervical intervertebral separation were 33.9% and 99.7%, respectively. Conclusion Approximately 70% of the cases with cervical intervertebral separations had various abnormal findings on CT imaging. The most common finding was intervertebral gas, but the sensitivity of intervertebral gas was not adequate.

Post-mortem computed tomography (CT) is a valuable tool in forensic medicine. Determination of cause of death may require examination of a corpse found in a frozen state. However, most radiologists are unfamiliar with the post-mortem appearance of frozen organs on CT. Here we present two cases that included CT study of the frozen brain. Both bodies were naturally frozen, and autopsies showed that the cause of death was hypothermia in both instances. On post-mortem CT images, the frozen brains exhibited hypodense areas resembling infarctions, but these were not in regions dominated by blood vessels. Residual open sulci were evident, suggesting that oedema was absent. These two features are helpful when diagnosing a frozen brain on CT images.

Many studies have reported that the degree of thyroid cartilage ossification correlates with age. However, its use in forensics has been limited by individual variation, tissue fragility, and observer subjectivity. We examined a new method for age estimation from the degree of ossification of thyroid cartilage using postmortem computed tomography (CT) and Bayesian analysis. The scoring of CT density values, ossification rate, and morphological changes was performed in 131 Japanese males (20-80years old), and an age estimation table was created and verified in 39 other Japanese males. We tried two types of prior probability; one was males undergoing postmortem CT imaging at our institute, and the other was the age composition of the male population in Japan. The differences in percentage in each age group were observed, especially in the ninth decade, but they were not large enough to change the result. Two decedents in their 30s and 80s could not be assigned an age group. Likelihood might have had more significant influence than prior probability. Bayesian approach and new scoring system of thyroid cartilage ossification might be useful as an age estimation method. Although the low posterior probability in decedents the age ≧70 remains a problem, the advantage of Bayesian estimation that it can sequentially update the age estimation table by factoring in exceptional data can solve this problem. In this study, accuracy of age estimation did not dramatically increase, however, Bayesian statistics might become a useful technique for examining any tissue samples subject to age-related calcification.

Traditional autopsy has changed little in the past century. In Japan, the rate of forensic autopsy in cases of unusual death is very low. Therefore, multi-slice computed tomography (CT) has been used to obtain imaging data instead of or in addition to autopsy in suspicious forensic cases. In our institute, postmortem multi-slice CT has been performed since 2009, and by 2014 there were over 1,000 cases. Our extensive experience with postmortem CT shows that in many cases of death by drug overdose, stomach contents exhibit high X-ray absorption. This article reviews the relationship between CT findings of stomach contents and toxicological analysis results in 23 cases of death by drug overdose. All cases (12 females and 11 males, aged 44 ± 11 years) known to have orally ingested drugs were included in this study. We assessed the slices of all stomach areas on consecutive axial CT images. Twenty cases (87%) showed high X-ray absorption in the stomach, while the other three did not demonstrate radio-dense stomach contents even though drug analysis detected lethal concentrations of drugs in the blood. In conclusion, drugs were frequently, but not always, visualized as contents with high X-ray absorption in the stomach. Postmortem gastric CT images can provide useful information in cases of oral drug intoxication if there are empty drug packages or a suicide note at the death scene. However, precise determination of the cause of death requires full autopsy in cases where there is no indication of suicide at the death scene.

This case report describes a woman who developed fatal gastric dilatation after binge eating. She called an ambulance because of stomach pain. When she arrived at the hospital, she did not look seriously ill. However, she rapidly became unconscious and collapsed immediately after she was laid on the examination table in a supine position. Postmortem chest x-ray and computed tomography showed right shift of the mediastinum and raised left diaphragm caused by massive gastric distension. Computed tomography showed no visible inferior vena cava. We think that her sudden deterioration was caused by movement of her stomach contents. Radiographic images provided some clues to the cause of her rapid collapse and death.

Reported risk factors for food/foreign body asphyxia include old age, poor dentition, and certain types of foods. The present report describes a rare autopsy case of a Japanese patient who ate mochi, a traditional rice cake, and died of asphyxiation. Multislice computed tomography (MSCT) as part of the pre-autopsy screening showed an impacted mochi cake in the lower tracheal space, facilitating forensic autopsy planning. In this report, we discuss the role of MSCT in cases of fatal food choking.

Sexual dimorphisms and age-dependent morphological features of the human coxal bone were quantitatively analyzed using homologous models created from three-dimensional (3D) computed tomography images of the pelvis (male: 514 samples, female: 388 samples, age 16-100). Bilateral average coxal images of each sex and age decade were generated separately through principle component analyses (PCA). By measuring average point-to-point distances of 8472 corresponding points (average corresponding point differences [ACPDs]) between each homologous coxal image and the average images, the sex of more than 93% of the samples was correctly assigned. Some principal components (PCs) detected in PCA of the homologous models of the samples correlated fairly well with age and are affected by features of the curvature of the iliac crest, the arcuate line and the greater sciatic notch. Moreover, separate PCA using the average images of each age decade successfully detected the first PCs, which were strongly correlated with age. However, neither multiple regression analysis using PCs related to age nor comparison of ACPDs with the average images of each age decade could produce accurate results for age decade assignment of unknown (blind) samples. Therefore, more detailed analysis of age-dependent morphological features would be necessary for actual age estimation. In addition, some laterality or left and right shape difference of the coxal bone images was also elucidated, and was more significant in females. Analysis of 3D structures using homologous models and PCA appears to be a potential technique to detect subsistent morphological changes of bones.

Objectives Infant cases frequently show a diffuse increase in the concentration of lung fields on post-mortem computed tomography (PMCT). However, the lungs often show simply atelectasis at autopsy in the absence of any other abnormal changes. Thus, we retrospectively reviewed the PMCT findings of lungs following sudden infant death and correlated them with the autopsy results. Materials and methods We retrospectively reviewed infant cases (0 year) who had undergone PMCT and a forensic autopsy at our institution between May 2009 and June 2013. Lung opacities were classified according to their type; consolidation, ground-glass opacity and mixed, as well as distribution; bilateral diffuse and areas of sparing. Statistical analysis was performed to assess the relationships among lung opacities, causes of death and resuscitation attempt. Results Thirty infant cases were selected, which included 22 sudden and unexplained deaths and 8 other causes of death. Resuscitation was attempted in 22 of 30 cases. Bilateral diffuse opacities were observed in 21 of the 30 cases. Of the 21 cases, 18 were sudden and unexplained deaths. Areas of sparing were observed in 4 sudden and unexplained deaths and 5 other causes of death. Distribution of opacities was not significantly associated with causes of death or resuscitation attempt. The 21 cases with bilateral diffuse opacities included 6 consolidations (4 sudden and unexplained deaths, 2 other causes of death), 4 ground-glass opacities (3 sudden and unexplained deaths and 1 other) and 11 mixed (11 sudden and unexplained deaths). Types of opacities were not significantly associated with causes of death or resuscitation attempt. Conclusion Atelectasis is very common in sudden and unexplained death of infants. Bilateral diffuse mixed opacity was observed only in sudden and unexplained deaths. Bilateral diffuse pure consolidation or ground-glass opacity was also observed in other causes of death.

This report describes the case of a man who developed fatal sigmoid volvulus that was identified on postmortem radiography before forensic autopsy. Postmortem radiography is useful for visualizing the body prior to autopsy. We discuss postmortem multidetector computed tomography that was tailored for optimum image quality to allow reconstruction of the fatal findings in multiple axes and in three dimensions, helping to pinpoint the anatomical sites of interest. This involves techniques such as manipulation of the scanning beam pitch and overlapping CT section acquisition. These techniques are best performed by personnel with CT technology training.

Objectives To evaluate the post-mortem computed tomography (PMCT) findings of intervertebral separation. Methods 10 subjects who had undergone PMCT and forensic autopsy were evaluated. The median age was 69 years (range, 25–89 years), and all subjects were men. 19 intervertebral separations were identified at autopsy. 2 radiologists reviewed the CT findings such as misalignment of the spine, intervertebral space widening, gas in the intervertebral space, and haemorrhage in the tissues surrounding the spine before and after autopsy using a 3D DICOM workstation. Results The observers detected 6 of 19 (32%) intervertebral separations before autopsy. After autopsy, they reviewed the CT considering the autopsy results and detected 13 of 19 (68%) intervertebral separations; misalignment ( n =7; 37%), widening ( n =5; 26%), gas ( n =2; 11%), and haemorrhage ( n =7; 37%). No finding indicating intervertebral separation was detected in 6 intervertebral separations. Conclusion Re-evaluation with autopsy results improved the detectability of intervertebral separation on PMCT. Adequate experience and training regarding the interpretation are required.

We sought to compare postmortem chest computed tomography (CT) features of drowning cases with autopsy findings, and to classify these features.We performed a retrospective analysis of high-resolution and multi-planar reconstruction chest CT images of drowning in 92 adults (54 men, 38 women; mean age 65.4 years) scanned before forensic autopsy. The average lung CT number was calculated from whole-lung images reconstructed on a 3D workstation. The statistically significant differences of CT numbers were assessed with an alpha level of 0.05.Postmortem chest CT image patterns were classified into six types: the two main types were ground-glass opacities with thickened pulmonary interstitium (n = 31), and a centrilobular distribution of ill-defined nodules along the airways (n = 38). Some cases were mixed type (n = 10). There were significant differences in CT numbers between each type. The remaining three types were consolidation (n = 5), emphysema and/or fibrosis (n = 4), and unclassifiable (n = 4).Postmortem CT images of drowning cases can be classified into three major types with a few exceptions.

A 3-year-old girl with no particular medical history complained of a stomachache and died on the way to the hospital. The autopsy revealed marked right ventricular hypertrophy and dilation with no other cardiac abnormalities. Microscopically, the pulmonary small arteries showed marked medial hypertrophy and varying degrees of intimal and adventitial thickening. We supposed that the cause of death was attributable to pulmonary arterial hypertension (PAH). PAH is a rare disease that can cause sudden, unexpected death at any age. Forensic pathologists should consider PAH in the differential diagnosis of sudden death.

Recent studies have reported that drowning victims frequently have fluid accumulation in the paranasal sinuses, most notably the maxillary and sphenoid sinuses. However, in our previous study, many non-drowning victims also had fluid accumulation in the sinuses. Therefore, we evaluated the qualitative difference in fluid accumulation between drowning and non-drowning cases in the present study. Thirty-eight drowning and 73 non-drowning cases were investigated retrospectively. The fluid volume and density of each case were calculated using a DICOM workstation. The drowning cases were compared with the non-drowning cases using the Mann-Whitney U-test because the data showed non-normal distribution. The median fluid volume was 1.82 (range 0.02-11.7) ml in the drowning cases and 0.49 (0.03-8.7) ml in the non-drowning cases, and the median fluid density was 22 (-14 to 66) and 39 (-65 to 77) HU, respectively. Both volume and density differed significantly between the drowning and non-drowning cases (p=0.001, p=0.0007). Regarding cut-off levels in the ROC analysis, the points on the ROC curve closest (0, 1) were 1.03ml (sensitivity 68%, specificity 68%, PPV 53%, NPV 81%) and 27.5 HU (61%, 70%, 51%, 77%). The Youden indices were 1.03ml and 37.8 HU (84%, 51%, 47%, 86%). When the cut-off level was set at 1.03ml and 27.5HU, the sensitivity was 42%, specificity 45%, PPV 29% and NPV 60%. When the cut-off level was set at 1.03ml and 37.8HU, sensitivity was 58%, specificity 32%, PPV 31% and NPV 59%.

Gastromalacia is a postmortem artifact resulting from autolysis of the gastric walls. Gastromalacia is autolytic rupture of the stomach caused by endogenous enzymes, and it is devoid of any vital reactions. The left leaf of the diaphragm is occasionally perforated by a ragged fenestration, with escape of gastric contents into the pleural cavity. This rupture may lead to pneumoperitoneum or pneumothorax. For diagnostic radiologists, gastromalacia is rarely encountered. Therefore, they should be aware of this entity to avoid misdiagnosis when performing postmortem radiography.

Referring to our experience with post-mortem computed tomography (CT), many hypothermic death cases presented a lack of increase in lung-field concentration, blood clotting in the heart, thoracic aorta or pulmonary artery, and urine retention in the bladder. Thus we evaluated the diagnostic performance of post-mortem CT on hypothermic death based on the above-mentioned three findings. Twenty-four hypothermic death subjects and 53 non-hypothermic death subjects were examined. Two radiologists assessed the presence or lack of an increase in lung-field concentration, blood clotting in the heart, thoracic aorta or pulmonary artery, and measured urine volume in the bladder. Pearson's chi-square test and Mann-Whitney U-test were used to assess the relationship between the three findings and hypothermic death. The sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of the diagnosis were also calculated. Lack of an increase in lung-field concentration and blood clotting in the heart, thoracic aorta or pulmonary artery were significantly associated with hypothermic death (p=0.0007, p

BackgroundOptimal contrast enhancement is crucial for the detection of coronary artery stenoses and atherosclerotic changes in coronary CT angiography (CTA).PurposeTo demonstrate the feasibility of using the cardiac output (CO) obtained from the test bolus injection data-set (COtest) as a factor in contrast injection rate revision of the following coronary CTA.Material and MethodsThe test bolus injection data-sets of 52 consecutive coronary CTAs were examined. COtest was calculated from the test bolus data-set. Aortic peak enhancement (APE) was measured on the following coronary CTA. We simulated the APE at a fixed contrast injection rate of 4 mL/s (simAPE) in each patient.ResultsThe ranges of COtest and simAPE were 2.82-7.56 L/min and 194-527 Hounsfield Units, respectively. There was a significant negative correlation (R = -0.802, P < 0.001) between simAPE and COtest.ConclusionCOtest can be used for injection rate revision on coronary CTA.

A 4-year-old girl who had been treated for asthma since the age of 2 years had a severe coughing fit and died suddenly. The patient had a history of occasional severe coughing fits, and these fits had been worsening in severity during the week before her death. Prior to death, she was taken to a clinician, and thymic hypertrophy was suspected based on chest X-ray findings. The clinician recommended that she visit a general hospital at a later date; however, she died that night. Postmortem radiology and autopsy revealed a large mass in the anterior mediastinum compressing the heart and airway, and no other findings attributable to sudden death were observed. Therefore, we concluded that the patient's death was attributable to acute respiratory and cardiac circulatory failure secondary to the pressure induced by the mass. Microscopically, the mass showed a cavernous structure composed of cystically dilated, thin-walled large vessels filled with blood. The final diagnosis was a cavernous hemangioma. Hemangiomas are the most common benign vascular anomalies seen in young children; however, mediastinal hemangiomas are rare and can cause life-threatening complications because of their size and location. Therefore, forensic pathologists should include hemangioma as a differential diagnosis in children with anterior mediastinal masses.

Gunshot injury has always been an important field of investigation in postmortem forensic radiology. The localization and retrieval of the bullet and of potentially important fragments are vital to these cases. Using postmortem multidetector-row computed tomography (MDCT) prior to forensic autopsy, we sought to illustrate the importance of this modality in the noninvasive characterization of gunshot wounds. We obtained and analyzed MDCT images in three cases of gunshot wounds (accidental close-range shotgun shooting, suicidal contact gunshot to the head and accidental long-range buckshot shooting). We discuss the value of postmortem MDCT findings in gunshot wound cases by comparing with forensic autopsy findings in Japan, a developing country with miserably low autopsy rate.

A female infant was found unresponsive at home. The mother alleged that she delivered the baby at home 13 days prior to the death. The mother did not have any prenatal examinations during the pregnancy and the infant was not examined by a doctor until death. The autopsy revealed that the cause of death was hypoplastic left heart syndrome (HLHS) and the infant's chest showed bilateral breast enlargement. Forensic pathologists may encounter very rare pathological findings with unexpected infant deaths. Some, like HLHS, are serious congenital heart defects related to the cause of death, and others are unique phenomena unrelated to the cause of death such as breast swelling and discharge called "witch's milk." In this case, we observed both findings.

Rationale: Total count data of a nuclear medicine image are calculated using a definite integral over total acquisition time (T), although γ-rays are completely random and irregular irrespective of their direction and gamma camera detector incidence location. However, random events could be used to create images by rearranging the time series and changing the data observation direction. We examined a filtering method wherein a time series of the count data from four directions is observed, four approximation equations are created, and the matrix size is enlarged by complementing it two-fold. Methods: Two phantoms and patient data were used here. Static and dynamic acquisition (T: 60 s or 300 s, time units: 1 s) were performed. The image data were a 3-dimensional data array within the timeline for each pixel, and the data analysis was performed for all pixels by fixing and varying the timeline in the data array. The set acquisition time data was rearranged into four patterns, a linear approximation equation was determined for each pattern (the least squares method), and then replotted in a 2-fold larger matrix area. Results: All approximation equations exhibited a correlation of R2 0.79. Four patterns: Normal, Inverse, Forward, and Backward, were constructed from the time series of acquisitions for a set time, and approximation equation data for four pixels were created from the data of one pixel. The apparent resolution increases when an image is partially enlarged, but this fell well short of the data that were actually acquired, although the apparent resolution was increased by implementing the proposed technique. Discussion: We proposed a novel filtering method that changes the matrix size without extending the imaging time by utilizing the acquisition events’ irregularity. Although the proposed technique requires changes in data processing software, it is extremely cost-effective because equipment modifications are unnecessary.

To evaluate the difference in sinus fluid volume and density between saltwater and freshwater drowning and diagnose saltwater drowning in distinction from freshwater drowning.Ninety-three drowning cases (22 saltwater and 71 freshwater) were retrospectively investigated; all had undergone post-mortem CT and forensic autopsy. Sinus fluid volume and density were calculated using a 3D-DICOM workstation, and differences were evaluated. Diagnostic performance of these indicators for saltwater drowning was evaluated using a cut-off value calculated by receiver operating characteristic (ROC) analysis.The median sinus fluid volume was 5.68 mL in cases of saltwater drowning (range 0.08 to 37.55) and 5.46 mL in cases of freshwater drowning (0.02 to 27.68), and the average densities were 47.28 (14.26 to 75.98) HU and 32.56 (-14.38 to 77.43) HU, respectively. While sinus volume did not differ significantly (p = 0.6000), sinus density was significantly higher in saltwater than freshwater drowning cases (p = 0.0002). ROC analysis for diagnosis of saltwater drowning determined the cut-off value as 37.77 HU, with a sensitivity of 77 %, specificity of 72 %, PPV of 46 % and NPV of 91 %.The average density of sinus fluid in cases of saltwater drowning was significantly higher than in freshwater drowning cases; there was no significant difference in the sinus fluid volume.• Sinus fluid density of saltwater drowning is significantly higher than freshwater drowning. • Cut-off value was 37.77 HU based on the ROC analysis. • The cut-off value translated to 91 % NPV for diagnosis of saltwater drowning.

An elderly woman was found dead in the aftermath of a fire. External inspection before autopsy showed no abnormal posture or hypermobility of the spine. Postmortem computed tomography and autopsy revealed a severe disruption of the 11th thoracic vertebra with extensive lordosis of the cervical spine and hyperkyphosis of the thoracic spine. The antemortem posture was able to be virtually rebuilt, clearly depicting the initial vertebral malposition. This led to a better understanding by lay people and helped in determination of the cause of death.

Gallbladder injuries are extremely rare in blunt trauma, with a reported incidence of

Recent reports have detailed common computed tomography (CT) findings in drowning victims, most notably fluid accumulation in the maxillary and sphenoidal sinuses. This CT finding could help forensic doctors to diagnose drowning. This study retrospectively investigated 151 subjects: 39 drowning and 112 non-drowning cases. Pearson's chi-square tests demonstrated that fluid accumulation in the maxillary or sphenoidal sinuses was associated significantly with drowning (p=0.0001). The sensitivity of the drowning diagnosis was 97%, specificity was 35%, accuracy was 51%, positive predictive value was 34% and negative predictive value was 98%. Drowning was significantly associated with fluid accumulation in the maxillary and sphenoidal sinuses, but the specificity and positive predictive value of the drowning diagnosis were poor. Although the presence of fluid in the maxillary and sphenoidal sinuses cannot be used to diagnose drowning, the absence of the fluid can be used to virtually exclude drowning.

Background The Fourier transform (FT) is an image-processing tool that can be used to analyze space or linear systems. We used the FT to analyze the shape of the subpubic line (SL) and the right greater sciatic notch area line (GSNAL) of the pelvis to identify sexing in computed tomographic (CT) images. Methods 120 bodies (60 male, 60 female) were scanned by multislice CT before autopsy. SL and GSNAL images were reconstructed using an image workstation. The range of the SL is between the bottom ends of the bilateral acetabulum, and the range of the right GSNAL is from the posterior superior iliac spine to the ischial tuberosity. Coordinates ( x , y ) of the bone outline were extracted from CT images and calculated by fast FT. The Mann–Whitney U test comparing the amplitude of each frequency was used to determine significant differences between the two populations. Multiple regression analyses were performed to find statistically significant amplitudes of each frequency. We verified the accuracy of prediction of the regression equation, and a Cohen's kappa coefficient was measured. Results Statistically significant differences of amplitude were found in the 2nd, 3rd, and 4th frequencies of the SL and the 1st, 3rd, and 4th frequencies of GSNAL. Adjusted R 2 using all amplitudes having a significant difference was 0.772. The accuracy was 0.983. Kappa coefficient was 0.983. Conclusion We could determine sexing from SL and GSNAL of the pelvis using FT with high accuracy. FT is a useful tool to analyze the curved shape of human bone.

A heat haematoma is an epidural haematoma often found in severely burned bodies as a heat-induced artefact.1e4 This haematoma is observed with intense burns of the head, which cause the dura mater to contract and exfoliate from the skull, resulting in the exudation of blood from the venous sinuses. A heat haematoma is formed when heat causes this exuded blood to coagulate. Macroscopically, a heat haematoma is brick red. It is not a vital reaction. In forensics, one must carefully distinguish a heat haematoma from an epidural haematoma caused by blunt trauma. Given the current wide use of post-mortem computed tomography (CT), the examiner should be able to distinguish these two haematomas on CT. The CT findings of heat haematomas are seldom reported.5,6 We report a case of heat haematoma in a post-mortem CT examination.

Since May 2009, we have performed multislice computed tomography (MSCT) prior to forensic autopsy for cases of suspicious death. In the present case, innumerable widely scattered nodules in both pulmonary fields on MSCT were indicative of miliary tuberculosis (TB). At autopsy, both lungs were submerged in formalin fluid immediately after removal from the body. Miliary TB was finally diagnosed based on microscopic findings. TB is a disease that autopsy room workers need to be aware of to protect themselves. Unfortunately, because little medical information about deceased individuals is usually available before forensic autopsy, the diagnosis of TB is frequently not made until autopsy. This leads to a much higher incidence of TB in autopsy room staff members even if they wear protective clothing. Therefore, MSCT before forensic autopsy may identify suspected cases of miliary TB in advance and thus help to prevent TB infection in forensic autopsy personnel.

A body in an advanced stage of mummification was found in a concrete apartment in Japan. Natural complete mummification is very rare in Japan’s humid and temperate climate. We performed multi-slice computed tomography (MSCT) to obtain information on the body prior to autopsy. MSCT clearly illustrated old fractures in the right lower leg. Bone resists destruction during body decomposition. If antemortem medical records of the deceased are available, MSCT scanning can provide information for positive identification. At autopsy, the cervical tissues presented as a dried mass, and it was difficult to separately remove the hyoid bone and thyroid cartilage. Fractures of the large horn of the hyoid bone and superior horn of the thyroid cartilage, which are not observed in all strangulation cases, strongly suggest criminal activity. The diagnosis of these fractures is of great value. In our case, MSCT revealed that there was no fracture in the hyoid bone or ossified area of the thyroid cartilage. Hard tissues are usually well preserved in mummies. Although MSCT images have limits in mummies because of the severe dryness of soft tissues and organs, they could become a useful tool not only for personal identification, but also for the identification of neck compression.

The use of post-mortem radiological imaging is becoming increasing widespread in forensic medicine. These images can help improve the quality and safety of autopsy. We report two cases of homicide victims that had broken pieces of a weapon in their skull. Postmortem multislice computed tomography (MSCT) demonstrated metal artifacts in the skull of two homicide cases. Autopsy showed that both artifacts were pieces broken off of a sharp instrument. Some possible benefits of postmortem MSCT include the ability to reconstruct visual images of weapons and the possible prevention of injury to autopsy personnel.

Gd2O3 nanoparticles were synthesized by using our original method for application as MRI contrast agents. The sample diameters were controlled in the range 18–66 nm by adjusting the annealing temperature between 773 and 1273 K in air or in an Ar atmosphere. Magnetization measurements were performed at 300 K, and the effective magnetic moment of each sample was calculated. They showed paramagnetism at 300 K and they had large effective magnetic moment μeff of 7.15–8.05 μB. MRI measurements were performed in 0.8 wt% agarose solution, and the Gd2O3 nanoparticles were found to work as effective T1-shortening MRI contrast agents.