Pseudolesion in the right parafissural liver parenchyma on CT: The base is found in embryology and collagen content.

BACKGROUND: Computed tomography (CT) images of livers may show a hypo-attenuated structure alongside the falciform ligament, which can be a focal fatty pseudolesion and can mimic a malignancy. The preferred location is on the right parafissural site, ventral in segment IVa/b. The etiology is not clear, nor is it known how the histology of this location develops. These are evaluated in this study. METHODS: 40 adult cadavers with autopsy and / or postmortem CT in a university hospital and a forensic center were included. Liver biopsies were taken at the left side of the falciform ligament as control, and at the right side as the possible precursor of a pseudolesion; these were examined for collagen and fat content. Cadavers with steatotic (>5% fat) or fibrotic (>2% collagen) control samples were excluded. RESULTS: Significantly more collagen was present in the right parafissural liver parenchyma: median 0.68% (IQR: 0.32-1.17%), compared to the left side 0.48% (IQR: 0.21-0.75%) (p 0.008), with equal fat content and CT attenuation values. The etiophysiology goes back to the demise of the umbilical venes in the early embryonic and neonatal period. CONCLUSIONS: The right parafissural area contains more collagen and an equal amount of fat compared to the control left side. This supports the hypothesis of delayed, 'third' inflow: the postnatal change in blood supply from umbilical to portal leaves the downstream parafissural area hypoperfused leading to hypoxia which in turn results in collagen accumulation and the persistence of paraumbilical veins of Sappey.

Automatic entry point planning for robotic post-mortem CT-based needle placement.

INTRODUCTION: Post-mortem computed tomography guided placement of co-axial introducer needles allows for the extraction of tissue and liquid samples for histological and toxicological analyses. Automation of this process can increase the accuracy and speed of the needle placement, thereby making it more feasible for routine examinations. To speed up the planning process and increase safety, we developed an algorithm that calculates an optimal entry point and end-effector orientation for a given target point, while taking constraints such as accessibility or bone collisions into account. TECHNIQUE: The algorithm identifies the best entry point for needle trajectories in three steps. First, the source CT data is prepared and bone as well as surface data are extracted and optimized. All vertices of the generated surface polygon are considered to be potential entry points. Second, all surface points are tested for validity within the defined hard constraints (reachability, bone collision as well as collision with other needles) and removed if invalid. All remaining vertices are reachable entry points and are rated with respect to needle insertion angle. Third, the vertex with the highest rating is selected as the final entry point, and the best end-effector rotation is calculated to avoid collisions with the body and already set needles. DISCUSSION: In most cases, the algorithm is sufficiently fast with approximately 5-6 s per entry point. This is the case if there is no collision between the end-effector and the body. If the end-effector has to be rotated to avoid collision, calculation times can increase up to 24 s due to the inefficient collision detection used here. In conclusion, the algorithm allows for fast and facilitated trajectory planning in forensic imaging.

Computer-assisted virtual autopsy using surgical navigation techniques.

UNLABELLED: OBJECTIVE; Virtual autopsy methods, such as postmortem CT and MRI, are increasingly being used in forensic medicine. Forensic investigators with little to no training in diagnostic radiology and medical laypeople such as state's attorneys often find it difficult to understand the anatomic orientation of axial postmortem CT images. We present a computer-assisted system that permits postmortem CT datasets to be quickly and intuitively resliced in real time at the body to narrow the gap between radiologic imaging and autopsy. CONCLUSION: Our system is a potentially valuable tool for planning autopsies, showing findings to medical laypeople, and teaching CT anatomy, thus further closing the gap between radiology and forensic pathology.

Virtobot 2.0: the future of automated surface documentation and CT-guided needle placement in forensic medicine.

In this paper we present the second prototype of a robotic system to be used in forensic medicine. The system is capable of performing automated surface documentation using photogrammetry, optical surface scanning and image-guided, post-mortem needle placement for tissue sampling, liquid sampling, or the placement of guide wires. The upgraded system includes workflow optimizations, an automatic tool-change mechanism, a new software module for trajectory planning and a fully automatic computed tomography-data-set registration algorithm. We tested the placement accuracy of the system by using a needle phantom with radiopaque markers as targets. The system is routinely used for surface documentation and resulted in 24 surface documentations over the course of 11 months. We performed accuracy tests for needle placement using a biopsy phantom, and the Virtobot placed introducer needles with an accuracy of 1.4 mm (±0.9 mm). The second prototype of the Virtobot system is an upgrade of the first prototype but mainly focuses on streamlining the workflow and increasing the level of automation and also has an easier user interface. These upgrades make the Virtobot a potentially valuable tool for case documentation in a scalpel-free setting that uses purely imaging techniques and minimally invasive procedures and is the next step toward the future of virtual autopsy.

Bone marrow edema induced by a bullet after a self-inflicted accidental firing.

We present a case of a postmortem finding of bone marrow edema in postmortem magnetic resonance imaging (PMMR) indirectly induced by a bullet, which barely missed the bone of a 92-year-old man found kneeling in front of his bed of a tidy apartment. Additionally, a selective postmortem computed tomography angiography (PMCTA) of the left leg was performed, visualizing a laceration of the left femoral vein by the bullet with consecutive contrast media extravasation. A vast pulmonary fat embolism was diagnosed and together with the blood loss found to be the cause of death.

Sudden death after chest pain: feasibility of virtual autopsy with postmortem CT angiography and biopsy.

PURPOSE: To determine the potential of minimally invasive postmortem computed tomographic (CT) angiography combined with image-guided tissue biopsy of the myocardium and lungs in decedents who were thought to have died of acute chest disease and to compare this method with conventional autopsy as the reference standard. MATERIALS AND METHODS: The responsible justice department and ethics committee approved this study. Twenty corpses (four female corpses and 16 male corpses; age range, 15-80 years), all of whom were reported to have had antemortem acute chest pain, were imaged with postmortem whole-body CT angiography and underwent standardized image-guided biopsy. The standard included three biopsies of the myocardium and a single biopsy of bilateral central lung tissue. Additional biopsies of pulmonary clots for differentiation of pulmonary embolism and postmortem organized thrombus were performed after initial analysis of the cross-sectional images. Subsequent traditional autopsy with sampling of histologic specimens was performed in all cases. Thereafter, conventional histologic and autopsy reports were compared with postmortem CT angiography and CT-guided biopsy findings. A Cohen κ coefficient analysis was performed to explore the effect of the clustered nature of the data. RESULTS: In 19 of the 20 cadavers, findings at postmortem CT angiography in combination with CT-guided biopsy validated the cause of death found at traditional autopsy. In one cadaver, early myocardial infarction of the papillary muscles had been missed. The Cohen κ coefficient was 0.94. There were four instances of pulmonary embolism, three aortic dissections (Stanford type A), three myocardial infarctions, three instances of fresh coronary thrombosis, three cases of obstructive coronary artery disease, one ruptured ulcer of the ascending aorta, one ruptured aneurysm of the right subclavian artery, one case of myocarditis, and one pulmonary malignancy with pulmonary artery erosion. In seven of 20 cadavers, CT-guided biopsy provided additional histopathologic information that substantiated the final diagnosis of the cause of death. CONCLUSION: Postmortem CT angiography combined with image-guided biopsy, because of their minimally invasive nature, have a potential role in the detection of the cause of death after acute chest pain.

Massive systemic fat embolism detected by postmortem imaging and biopsy.

Postmortem computed tomography (pmCT) and pmCT angiography (pmCTA) provide a minimally invasive method to determine the cause of death. Postmortem image-guided biopsy allows for precise sampling of histological specimens. This case study describes the findings of lethal systemic fat embolism (FE) on whole-body unenhanced pmCT, pmCTA, and image-guided biopsy, with autopsy and histopathologic correlation. Unenhanced pmCT revealed a distinct fat level on top of sedimented layers of corpuscular blood particles and serum in the arterial system and pulmonary trunk. Subsequent pmCTA showed reproducible results, and image-guided biopsy confirmed fatal FE. pm CT/pmCTA combined with image-guided biopsy established the cause of death as right heart failure as a result of systemic fatal FE prior to autopsy. All imaging findings were consistent with traditional autopsy and histological specimens. This unique case demonstrates new imaging findings in massive, fatal FE and highlights that postmortem imaging, supplemented by image-guided biopsy, may detect the cause of death prior to traditional autopsy.

"Drug mules" as a radiological challenge: sensitivity and specificity in identifying internal cocaine in body packers, body pushers and body stuffers by computed tomography, plain radiography and Lodox.

PURPOSE: The purpose of our study was to retrospectively evaluate the specificity, sensitivity and accuracy of computed tomography (CT), digital radiography (DR) and low-dose linear slit digital radiography (LSDR, Lodox(®)) in the detection of internal cocaine containers. METHODS: Institutional review board approval was obtained. The study collectively consisted of 83 patients (76 males, 7 females, 16-45 years) suspected of having incorporated cocaine drug containers. All underwent radiological imaging; a total of 135 exams were performed: nCT=35, nDR=70, nLSDR=30. An overall calculation of all "drug mules" and a specific evaluation of body packers, pushers and stuffers were performed. The gold standard was stool examination in a dedicated holding cell equipped with a drug toilet. RESULTS: There were 54 drug mules identified in this study. CT of all drug carriers showed the highest diagnostic accuracy 97.1%, sensitivity 100% and specificity 94.1%. DR in all cases was 71.4% accurate, 58.3% sensitive and 85.3% specific. LSDR of all patients with internal cocaine was 60% accurate, 57.9% sensitive and 63.4% specific. CONCLUSIONS: CT was the most accurate test studied. Therefore, the detection of internal cocaine drug packs should be performed by CT, rather than by conventional X-ray, in order to apply the most sensitive exam in the medico-legal investigation of suspected drug carriers. Nevertheless, the higher radiation applied by CT than by DR or LSDR needs to be considered. Future studies should include evaluation of low dose CT protocols in order to address germane issues and to reduce dosage.

Blood aspiration as a vital sign detected by postmortem computed tomography imaging.

Blood aspiration is a significant forensic finding. In this study, we examined the value of postmortem computed tomography (CT) imaging in evaluating findings of blood aspiration. We selected 37 cases with autopsy evidence of blood in the lungs and/or in the airways previously submitted to total-body CT scanning. The CT-images were retrospectively analyzed. In one case with pulmonary blood aspiration, biopsy specimens were obtained under CT guide for histological examination. In six cases, CT detected pulmonary abnormalities suggestive of blood aspiration, not mentioned in the autopsy reports. CT reconstructions provided additional data about the distribution and extent of aspiration. In one needle-biopsied case, the pulmonary specimens showed blood in the alveoli. We suggest the use of CT imaging as a tool complementary to traditional techniques in cases of blood aspiration to avoid misdiagnosis, to guide the investigation of lung tissue, and to allow for more evidence-based inferences on the cause of death.

Diagnosis of fatal pulmonary fat embolism with minimally invasive virtual autopsy and post-mortem biopsy.

We report a case of a 78-year-old female with a proximal femur fracture caused by an accidental fall who died suddenly 1h after orthopaedic prosthesis insertion. Post-mortem computed tomography (CT) scan and histological examination of samples obtained with post-mortem percutaneous needle biopsies of both lungs were performed. Analysis of the medical history and the clinical scenario immediately before death, imaging data, and biopsy histology established the cause of death without proceeding to traditional autopsy. It was determined to be acute right ventricular failure caused by massive pulmonary fat embolism. Although further research in post-mortem imaging and post-mortem tissue sampling by needle biopsies is necessary, we conclude that the use of CT techniques and percutaneous biopsy, as additional tools, can offer a viable alternative to traditional autopsy in selected cases and may increase the number of minimally invasive forensic examinations performed in the future.