Journal of Forensic Radiology and Imaging最新文献

At the Zurich Institute of Forensic Medicine, post-mortem computed tomography (PMCT) has an important role. During an autopsy, access to the PMCT images can be important to localize findings. We present an approach to overcome the limitations of current systems for displaying medical image data during autopsy. The presented system uses augmented reality to display DICOM image stacks with basic functionality. In addition, we report the first test of the system during autopsy.

The high cost of commercial components and parts for post-mortem computed tomography angiography (PMCTA) has resulted in the development of a very low cost PMCTA-kit. It contains ubiquitous parts from hardware stores, and rapid prototyping derived models for 3D-printing. Design specifications have been tested and improved after finite-element modelling. A case study performed in using the final PMCTA kit parts for a PMCTA shows perfect vascular contrast without relevant leaks.

Purpose

To determine whether the use of post-mortem computed tomography (PMCT) measurements of blood radio-density within the right atrium could differentiate decedents grouped according to cause of death as controls, fresh-water or salt-water drowning.

Methods

PMCT images from drowning cases comprising fresh-water (n = 34) and salt-water (n = 30) incidents and also controls (n = 48) were selected from a forensic database. Four regions of interest (ROIs) were placed within the right atrium of the heart using a standardised procedure that accounted for sedimentation effects. Statistical analysis was undertaken using a two-way random effect inter-class correlation (ICC) test set for absolute agreement and then a repeated measures ANOVA test.

Results

ICC tests demonstrated very good agreement for the readings for all ROIs (ICC ≥ 0.90). A statistically significant sedimentation effect was observed across the anterior middle and posterior regions of the right atrium (F(2,218) = 212, p < .001). There was no significant effect of Group (F(2,109) = 0.481, p = .620), nor was there a significant interaction between group and Region (F(4,218) = 2.09, p = .083).

Conclusions

Aspiration of fluid while drowning may cause changes in blood concentration. Blood concentration is measured using radio-density on PMCT images. PMCT radio-density data extracted from regional ROIs demonstrates the presence of the sedimentation effect but is not supportive of classification of drowning. There was good agreement between readers in the performance of this task.

Body packing is the internal concealment of illicit substances within the alimentary tract with the intention of smuggling them across borders and evading law enforcement. Medical imaging plays an important role in the management of suspected body packers through the identification of drug packets, as well as recognising medical complications. This literature review aims to determine whether abdominal radiography (AXR) or computed tomography [CT] is the most appropriate imaging modality for the detection of illegal substances in suspected body packers, taking into consideration the sensitivity, specificity and radiation dose. In addition, whether CT could completely replace the use of radiography given the radiation dose of CT can be decreased to levels that can be comparable to x-ray. AXR is a widely available and relatively low-dose modality commonly performed as the first line of imaging for suspected body packers but is very unreliable due to its highly variable sensitivity of 40–90% and high false positive and false negative rates. CT has a reported sensitivity and specificity of close to 100% but is not used as an initial imaging modality due to its higher radiation dose. CT is not only superior in sensitivity and specificity, but radiologists are also able to accurately identify the number of packets and their locations within the body while delivering radiation doses similar or even below the average dose of an AXR. The use of a low-dose CT protocol with reduced mAs is now preferred as the initial screening tool for suspected body packers over AXR.

Forensic injury interpretation can be greatly enhanced by the use of 3D-surface documentation, also in conjunction with full body scans. For static juxtapositioning, a rigid shape transfer from weapon or injury causing object to the victim's skin or bone will be assumed for patterned injuries, upon which an object's shape directly explains the shape of an injury. Forensic pathology expertise may be essential in reading the resulting 3D shape match attempts, particularly when in due process of injury causation, deformation of either the object/weapon or victim's tissues occurred, causing a dynamic rather than rigid shape transfer.

In this case, a 3D match using manual forensic juxtapositioning of punctate and elongated striate forehead skin abrasions and a hairbrush yielded a partial but not perfect match. Qualitative medicolegal appreciation of the partial match result clearly indicated centrifugal brush bristle deformation after impact, causing a centrifugal abrasion pattern, thus having dynamically extended an initially stationary punctate abrasion and bristle end shape match. This was corroborated by both the elasticity of the bristles and the brush frame fracture. Presence and location of the fracture indicated a relatively high force between the brush handle on one hand and the bristles on the other.

This case shows how the application of targeted forensic pathology interpretation can elucidate what technically only is a partial 3D match and add re-constructive meaning. Generally, more research is needed in establishing just how technical sciences and specific medicolegal expertise are best integrated.

We present two cases of diffusely decreased liver attenuation on post-mortem computed tomography (CT) which is lower than that on ante-mortem CT. Cases include a 37-year-old female whose cause of death was related to myelodysplastic syndrome (Case #1) and an 88-year-old female whose cause of death was related to malignant lymphoma (Case #2). We compared post-mortem CT (PMCT) liver attenuations with those on ante-mortem CT (AMCT). For Case #1, average AMCT values of the right/left liver were 46.1/50.0 Hounsfield Units (HU) 2 days ante-mortem and PMCT values of the right/left liver were 33.9/38.4 HU 3 h post-mortem. For Case #2, average AMCT values were 61.4/54.9 HU 5 days ante-mortem and PMCT values of the right/left liver were 38.2/40.6 HU 2 h post-mortem. In both Case # 1 and #2, decreased liver attenuations were found on PMCT. Further, autopsy revealed diffuse hepatocellular hemorrhage, deficits, and necrosis in Case #1, and liver infiltration of lymphoma in Case #2. These pathological findings were considered to be related to diffusely decreased liver attenuation on PMCT in conjunction with remarkable deterioration of hepatobiliary function before death. The observed decreases in liver attenuation on PMCT may be attributed mainly to hepatic pathological changes just prior to death. PMCT liver attenuation does not necessarily reflect the ante-mortem state some time before death, and it is therefore necessary to be careful when presuming the ante-mortem hepatic pathological conditions from only PMCT. This attenuation change should be taken into account during PMCT interpretation.

The purpose of this study is to evaluate the usefulness of a simple method for readjustment of positioning in post-mortem (PM) head computed tomography (CT) imaging. Two hundred and twenty-five autopsied cases were used to test our proposed method. The coordinates of 5 landmarks on axial planes in PM head CT images were determined manually to calculate Yaw, Pitch, and Roll angles for the sake of readjustment. A radiologist and a forensic pathologist evaluated the readjustment by mutual agreement. Intraclass correlation coefficients (ICCs) for Yaw, Pitch, and Roll angles were measured for 3 operators. Similarity in AM and PM images after the readjustment was tested for 18 cases to evaluate the usefulness of the readjustment in personal identification for forensic cases. If similarity of the same person showed the highest value among all combinations in 18 cases, it was regarded as the correct identification. The processing time of our readjustment was limited to within 2 min per case. The orbitomeatal line (OML) was included in a single axial plane in 96.4% (217/225) of the cases after the readjustment. Reproducibility for determining landmarks showed acceptable ICC. Moreover, rank-one identification rate before and after readjustment were 16.7% (3/18) and 88.9% (16/18), respectively. Thus, our method for semi-automated readjustment exhibited potential usefulness in forensic cases. A simple method for semi-automatic readjustment would be a useful tool for post-mortem CT imaging with high reproducibility and a short processing time.