Fatal thoracic impalement on postmortem imaging

In the present paper, the authors describe a case of fatal thoracic impalement in a victim of a road traffic accident, by penetration of a metal handrail. The driver lost control of his car while overtaking three cars. Due to the force of the vehicle collision with a metal railing, the upper cross bar penetrated the front of the car and subsequently the driver was pierced by the center-pillar in the car. Death occurred at the scene of the accident. Postmortem, computed tomography, computed tomography angiography and a magnetic resonance tomography were performed and revealed severe heart destruction and hemorrhage as cause of death. The present case report shows that postmortem imaging might have value as a screening method to decide whether arising forensic questions can be answered just by imaging like in the presented case or if further examinations such as conventional autopsy are required.

Mesh-based vs. Image-based Statistical Appearance Model of the Human Femur: a Preliminary Comparison Study for the Creation of Finite Element Meshes

Statistical models have been recently introduced in computational orthopaedics to investigate the bone mechanical properties across several populations. A fundamental aspect for the construction of statistical models concerns the establishment of accurate anatomical correspondences among the objects of the training dataset. Various methods have been proposed to solve this problem such as mesh morphing or image registration algorithms. The objective of this study is to compare a mesh-based and an image-based statistical appearance model approaches for the creation of nite element(FE) meshes. A computer tomography (CT) dataset of 157 human left femurs was used for the comparison. For each approach, 30 finite element meshes were generated with the models. The quality of the obtained FE meshes was evaluated in terms of volume, size and shape of the elements. Results showed that the quality of the meshes obtained with the image-based approach was higher than the quality of the mesh-based approach. Future studies are required to evaluate the impact of this finding on the final mechanical simulations.

Chapter II: Diagnostic methods

Non-invasive vascular studies can provide crucial information on the presence, location, and severity of critical limb ischaemia (CLI), as well as the initial assessment or treatment planning. Ankle-brachial index with Doppler ultrasound, despite limitations in diabetic and end-stage renal failure patients, is the first-line evaluation of CLI. In this group of patients, toe-brachial index measurement may better establish the diagnosis. Other non-invasive measurements, such as segmental limb pressure, continuous-wave Doppler analysis and pulse volume recording, are of limited accuracy. Transcutaneous oxygen pressure (TcPO(2)) measurement may be of value when rest pain and ulcerations of the foot are present. Duplex ultrasound is the most important non-invasive tool in CLI patients combining haemodynamic evaluation with imaging modality. Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) are the next imaging studies in the algorithm for CLI. Both CTA and MRA have been proven effective in aiding the decision-making of clinicians and accurate planning of intervention. The data acquired with CTA and MRA can be manipulated in a multiplanar and 3D fashion and can offer exquisite detail. CTA results are generally equivalent to MRA, and both compare favourably with contrast angiography. The individual use of different imaging modalities depends on local availability, experience, and costs. Contrast angiography represents the gold standard, provides detailed information about arterial anatomy, and is recommended when revascularisation is needed.

Unique paleopathology in a pre-Columbian mummy remnant from Southern Peru--severe cervical rotation trauma with subluxation of the axis as cause of death

We describe the multidisciplinary findings in a pre-Columbian mummy head from Southern Peru (Cahuachi, Nazca civilisation, radiocarbon dating between 120 and 750 AD) of a mature male individual (40-60 years) with the first two vertebrae attached in pathological position. Accordingly, the atlanto-axial transition (C1/C2) was significantly rotated and dislocated at 38° angle associated with a bulging brownish mass that considerably reduced the spinal canal by circa 60%. Using surface microscopy, endoscopy, high-resolution multi-slice computer tomography, paleohistology and immunohistochemistry, we identified an extensive epidural hematoma of the upper cervical spinal canal-extending into the skull cavity-obviously due to a rupture of the left vertebral artery at its transition between atlas and skull base. There were no signs of fractures of the skull or vertebrae. Histological and immunohistochemical examinations clearly identified dura, brain residues and densely packed corpuscular elements that proved to represent fresh epidural hematoma. Subsequent biochemical analysis provided no evidence for pre-mortal cocaine consumption. Stable isotope analysis, however, revealed significant and repeated changes in the nutrition during his last 9 months, suggesting high mobility. Finally, the significant narrowing of the rotational atlanto-axial dislocation and the epidural hematoma probably caused compression of the spinal cord and the medulla oblongata with subsequent respiratory arrest. In conclusion, we suggest that the man died within a short period of time (probably few minutes) in an upright position with the head rotated rapidly to the right side. In paleopathologic literature, trauma to the upper cervical spine has as yet only very rarely been described, and dislocation of the vertebral bodies has not been presented.

Reconstruction and 3D visualisation based on objective real 3D based documentation

Reconstructions based directly upon forensic evidence alone are called primary information. Historically this consists of documentation of findings by verbal protocols, photographs and other visual means. Currently modern imaging techniques such as 3D surface scanning and radiological methods (Computer Tomography, Magnetic Resonance Imaging) are also applied. Secondary interpretation is based on facts and the examiner's experience. Usually such reconstructive expertises are given in written form, and are often enhanced by sketches. However, narrative interpretations can, especially in complex courses of action, be difficult to present and can be misunderstood. In this report we demonstrate the use of graphic reconstruction of secondary interpretation with supporting pictorial evidence, applying digital visualisation (using 'Poser') or scientific animation (using '3D Studio Max', 'Maya') and present methods of clearly distinguishing between factual documentation and examiners' interpretation based on three cases. The first case involved a pedestrian who was initially struck by a car on a motorway and was then run over by a second car. The second case involved a suicidal gunshot to the head with a rifle, in which the trigger was pushed with a rod. The third case dealt with a collision between two motorcycles. Pictorial reconstruction of the secondary interpretation of these cases has several advantages. The images enable an immediate overview, give rise to enhanced clarity, and compel the examiner to look at all details if he or she is to create a complete image.

Comparison of implant stability by means of resonance frequency analysis for flapless and conventionally inserted implants

Background: Resonance frequency analysis (RFA) is a noninvasive technique for the quantitative assessment of implant stability. Information on the implant stability quotient (ISQ) of transmucosally inserted implants is limited. Purpose: The aim of this investigation was to compare the ISQ of conventionally inserted implants by raising a muco-periostal flap with implants inserted using a flapless procedure. Materials and Methods: Forty elderly patients with complete edentulous maxilla were consecutively admitted for treatment with implant-supported prostheses. A computer tomography was obtained for the computer-assisted implant planning. One hundred ten implants were placed conventionally in 23 patients (flap-group) and 85 implants in 17 patients by means of the flapless method (flapless-group) using a stereolithographic template. RFA measurements were performed after implant placement (baseline) and after a healing time of 12 weeks (reentry). Results: All implants exhibited clinically and radiographically successful osseointegration. Bone level did not change significantly neither for genders nor type of surgical protocol. Mean ISQ values of the flapless-group were significantly higher at baseline (p < .001) and at reentry (p < .001) compared with the flap-group. The ISQ values were significantly lower at reentry compared with baseline for the flap-group (p = .028) but not for the flapless-group. This group showed a moderate, but insignificant increase. RFA measurements of males resulted in ISQ values that were thoroughly higher as compared with females at both time-points in both groups. Correlation between RFA and bone level was not found. Conclusions: The flapless procedure showed favorable conditions with regard to implant stability and crestal bone level. Some changes of the ISQ values that represent primary (mechanical) and secondary (bone remodeling) implant stability were observed in slight favor of the flapless method and male patients. In properly planned and well-selected cases, the minimal invasive transmucosal technique using a drill-guide is a safe procedure.

[MRI-based diagnosis of giant cell arteritis]

The giant cell arteritis and its symptoms are usually non-specific and accompanied with symptoms of polymyalgia rheumatica. As complications of the giant cell arteritis ischemia, infarction or rupture of the damaged vessel can occur. We report on a 56-year-old female patient, who suffered for one year about weight loss, tiredness and intolerance as well as symptoms of polymyalgia rheumatica. Gastroscopy and colonoscopy showed normal findings. In the context of the malignancy search we made a computer tomography and magnet resonance tomography. The data showed an enlargement and an enhancement of the aorta, which led us to the suspicion of a giant cell arteritis. We started immediately with a medical treatment. The biopsy of the arteries temporales supported histological the diagnosis.

Pathophysiology and diagnosis of nephrocalcinosis

Nephrocalcinosis is the result of a myriad of hereditary or acquired diseases in the calcium, phosphate or oxalate metabolism that lead to deposition of calcium containing precipitates within the kidney. Nephrocalcinosis and nephrolithiasis are pathophysiologically tightly related and often co-exist. In the case of recurrent nephrolithiasis, nephrocalcinosis has to be excluded. Stone analysis can yield important clues to the underlying disease process. The best way to diagnose nephrocalcinosis and an accompanying nephrolithiasis is by native computer tomography scans. Untreated, nephrocalcinosis will lead to a progressive decline in renal function and eventually to end stage renal disease. Thus, for each case, the underlying disease process has to be determined and a causative therapy initiated.

Accuracy considerations in navigated cup placement for total hip arthroplasty

Computer assisted orthopaedic surgery (CAOS) technology has recently been introduced to overcome problems resulting from acetabular component malpositioning in total hip arthroplasty. Available navigation modules can conceptually be categorized as computer tomography (CT) based, fluoroscopy based, or image-free. The current study presents a comprehensive accuracy analysis on the computer assisted placement accuracy of acetabular cups. It combines analyses using mathematical approaches, in vitro testing environments, and an in vivo clinical trial. A hybrid navigation approach combining image-free with fluoroscopic technology was chosen as the best compromise to CT-based systems. It introduces pointer-based digitization for easily assessable points and bi-planar fluoroscopy for deep-seated landmarks. From the in vitro data maximum deviations were found to be 3.6 degrees for inclination and 3.8 degrees for anteversion relative to a pre-defined test position. The maximum difference between intraoperatively calculated cup inclination and anteversion with the postoperatively measured position was 4 degrees and 5 degrees, respectively. These data coincide with worst cases scenario predictions applying a statistical simulation model. The proper use of navigation technology can reduce variability of cup placement well within the surgical safe zone. Surgeons have to concentrate on a variety of error sources during the procedure, which may explain the reported strong learning curves for CAOS technologies.

Simultaneous, bilateral anterior ischemic optic neuropathy (AION) in polycythemia vera: a case report

BACKGROUND: Polycythemia vera (PV) is a hemopoetic disorder. Apparently, although thrombosis accounts for the majority of morbidity, AION has not been associated with PV so far. PATIENT AND FINDINGS: A 63 y-old woman with PV was hospitalized because of acute liver failure. She also experienced bilateral painless loss of vision. Bilateral, pale optic disc swelling with flame-like hemorrhages, more pronounced in the right eye, constricted visual fields, and relative afferent papillary defect (RAPD) on the right side were present. Computer tomography scan revealed no signs of intraorbital pathology, elevated intracranial pressure or hemorrhages. CLINICAL COURSE: We interpreted the findings as AION associated with the hyperviscosity syndrome. Liver transplantation had to be carried out in the next days. Three weeks later, vision improved slightly, but RAPD persisted, and disc pallor developed in both eyes. The patient died two months later. DISCUSSION: Central retinal artery and vein occlusions have been described as complications of Essential thrombocythemia, but not of PV. We observed a rare case of bilateral neuropathy suggestive of AION. This condition has so far not been associated with PV.

Gastroesophageal reflux and pulmonary fibrosis in scleroderma: a study using pH-impedance monitoring

RATIONALE: Interstitial lung disease (ILD) in patients with systemic sclerosis (SSc) is associated with increased morbidity and mortality. Gastroesophageal reflux (GER) is considered a contributing factor in the pathogenesis of ILD. OBJECTIVES: To characterize GER (acid and nonacid) in patients with SSc with and without ILD. METHODS: Patients with SSc underwent pulmonary high-resolution computer tomography (HRCT) scan and 24-hour impedance-pH monitoring off-proton pump inhibitor therapy. The presence of pulmonary fibrosis was assessed using validated HRCT-scores. Reflux monitoring parameters included number of acid and nonacid reflux episodes, proximal migration of the refluxate, and distal esophageal acid exposure. Unless otherwise specified, data are presented as median (25th-75th percentile). MEASUREMENTS AND MAIN RESULTS: Forty consecutive patients with SSc (35 female; mean age, 53 yr; range, 24-71; 15 patients with diffuse and 25 with limited SSc) were investigated; 18 (45%) patients with SSc had pulmonary fibrosis (HRCT score >or= 7). Patients with SSc with ILD had higher (P < 0.01) esophageal acid exposure (10.3 [7.5-15] vs. 5.2 [1.5-11]), higher (P < 0.01) number of acid (41 [31-58] vs. 19 [10-23]) and nonacid (25 [20-35] vs. 17 [11-19]) reflux episodes, and higher (P < 0.01) number of reflux episodes reaching the proximal esophagus (42.5 [31-54] vs. 15 [8-22]) compared with patients with SSc with normal HRCT scores. Pulmonary fibrosis scores (HRCT score) correlated well with the number of reflux episodes in the distal (r(2) = 0.637) and proximal (r(2) = 0.644) esophagus. CONCLUSIONS: Patients with SSc with ILD have more severe reflux (i.e., more reflux episodes and more reflux reaching the proximal esophagus). Whether or not the development of ILD in patients with SSc can be prevented by reflux-reducing treatments needs to be investigated.

Virtopsy: postmortem imaging of laryngeal foreign bodies

CONTEXT: Death from corpora aliena in the larynx is a well-known entity in forensic pathology. The correct diagnosis of this cause of death is difficult without an autopsy, and misdiagnoses by external examination alone are common. OBJECTIVE: To determine the postmortem usefulness of modern imaging techniques in the diagnosis of foreign bodies in the larynx, multislice computed tomography, magnetic resonance imaging, and postmortem full-body computed tomography-angiography were performed. DESIGN: Three decedents with a suspected foreign body in the larynx underwent the 3 different imaging techniques before medicolegal autopsy. RESULTS: Multislice computed tomography has a high diagnostic value in the noninvasive localization of a foreign body and abnormalities in the larynx. The differentiation between neoplasm or soft foreign bodies (eg, food) is possible, but difficult, by unenhanced multislice computed tomography. By magnetic resonance imaging, the discrimination of the soft tissue structures and soft foreign bodies is much easier. In addition to the postmortem multislice computed tomography, the combination with postmortem angiography will increase the diagnostic value. CONCLUSIONS: Postmortem, cross-sectional imaging methods are highly valuable procedures for the noninvasive detection of corpora aliena in the larynx.

Finite element analysis for prediction of bone strength

Article preview View full access options BoneKEy Reports | Review Print Email Share/bookmark Finite element analysis for prediction of bone strength Philippe K Zysset, Enrico Dall'Ara, Peter Varga & Dieter H Pahr Affiliations Corresponding author BoneKEy Reports (2013) 2, Article number: 386 (2013) doi:10.1038/bonekey.2013.120 Received 03 January 2013 Accepted 25 June 2013 Published online 07 August 2013 Article tools Citation Reprints Rights & permissions Abstract Abstract• References• Author information Finite element (FE) analysis has been applied for the past 40 years to simulate the mechanical behavior of bone. Although several validation studies have been performed on specific anatomical sites and load cases, this study aims to review the predictability of human bone strength at the three major osteoporotic fracture sites quantified in recently completed in vitro studies at our former institute. Specifically, the performance of FE analysis based on clinical computer tomography (QCT) is compared with the ones of the current densitometric standards, bone mineral content, bone mineral density (BMD) and areal BMD (aBMD). Clinical fractures were produced in monotonic axial compression of the distal radii, vertebral sections and in side loading of the proximal femora. QCT-based FE models of the three bones were developed to simulate as closely as possible the boundary conditions of each experiment. For all sites, the FE methodology exhibited the lowest errors and the highest correlations in predicting the experimental bone strength. Likely due to the improved CT image resolution, the quality of the FE prediction in the peripheral skeleton using high-resolution peripheral CT was superior to that in the axial skeleton with whole-body QCT. Because of its projective and scalar nature, the performance of aBMD in predicting bone strength depended on loading mode and was significantly inferior to FE in axial compression of radial or vertebral sections but not significantly inferior to FE in side loading of the femur. Considering the cumulated evidence from the published validation studies, it is concluded that FE models provide the most reliable surrogates of bone strength at any of the three fracture sites.

Embedding of human vertebral bodies leads to higher ultimate load and altered damage localisation under axial compression

Computer tomography (CT)-based finite element (FE) models of vertebral bodies assess fracture load in vitro better than dual energy X-ray absorptiometry, but boundary conditions affect stress distribution under the endplates that may influence ultimate load and damage localisation under post-yield strains. Therefore, HRpQCT-based homogenised FE models of 12 vertebral bodies were subjected to axial compression with two distinct boundary conditions: embedding in polymethylmethalcrylate (PMMA) and bonding to a healthy intervertebral disc (IVD) with distinct hyperelastic properties for nucleus and annulus. Bone volume fraction and fabric assessed from HRpQCT data were used to determine the elastic, plastic and damage behaviour of bone. Ultimate forces obtained with PMMA were 22% higher than with IVD but correlated highly (R2 = 0.99). At ultimate force, distinct fractions of damage were computed in the endplates (PMMA: 6%, IVD: 70%), cortex and trabecular sub-regions, which confirms previous observations that in contrast to PMMA embedding, failure initiated underneath the nuclei in healthy IVDs. In conclusion, axial loading of vertebral bodies via PMMA embedding versus healthy IVD overestimates ultimate load and leads to distinct damage localisation and failure pattern.

D-dimer to Rule Out Pulmonary Embolism in Renal Insufficiency

BACKGROUND D-dimer levels are often elevated in renal insufficiency. The diagnostic accuracy of D-dimer to rule out pulmonary embolism in patients with renal insufficiency is unclear. METHODS We evaluated the data of patients presenting to our Emergency Department and receiving computed tomography angiography to rule out pulmonary embolism with measurement of D-dimer and creatinine. Glomerular filtration rate was calculated using the Chronic Kidney Disease Epidemiology Collaboration formula. RESULTS There were 1305 patients included; 1067 (82%) had an estimated glomerular filtration rate (eGFR) exceeding 60 mL/min, 209 (16%) 30-60 mL/min, and 29 (2%) <30 mL/min. One hundred fifty-two patients (12%) had D-dimer below 500 μg/L. eGFR (R = -0.1122) correlated significantly with D-dimer (P <.0001). One hundred sixty-nine patients (13%) were found to have pulmonary embolism. Sensitivity of D-dimer for patients with an eGFR >60 mL/min was 96% (confidence interval [CI], 0.93-0.99) and 100% (CI, 100-100) for those with 30-60 mL/min, while specificity decreased significantly with impaired renal function. Area under the curve of the receiver operating characteristic for D-dimer was 0.734 in patients with an eGFR of >60 mL/min, and 0.673 for 30-60 mL/min. CONCLUSIONS D-dimer levels were elevated in patients with an eGFR <60 mL/min, but proved to be highly sensitive for the exclusion of pulmonary embolism. However, because almost all patients with impaired renal function had elevated D-dimer irrespective of the presence of pulmonary embolism, studies should be performed to determine renal function-adjusted D-dimer cutoffs.