Biomedical subjects

Christoph Ozdoba

Publications and source records attributed to Christoph Ozdoba.

17 recordsLinked to original sources

PubMed2006

Detection of regional blood perfusion changes in epileptic seizures with dynamic brain perfusion CT--a pilot study.

BACKGROUND AND PURPOSE: Perfusion CT (P-CT) is used for acute stroke management, not, however, for evaluating epilepsy. To test the hypothesis that P-CT may identify patients with increased regional cerebral blood flow during subtle status epilepticus (SSE), we compared P-CT in SSE to different postictal conditions. METHODS: Fifteen patients (mean age 47 years, range 21-74) underwent P-CT immediately after evaluation in our emergency room. Asymmetry indices between affected and unaffected hemispheres were calculated for regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), and mean transit time (MTT). Regional perfusion changes were compared to EEG findings. RESULTS: Three patients in subtle status epilepticus (group 1) had increased regional perfusion with electro-clinical correlate. Six patients showed postictal slowing on EEG corresponding to an area of regional hypoperfusion (group 2). CT and EEG were normal in six patients with a first epileptic seizure (group 3). Cluster analysis of asymmetry indices separated SSE from the other two groups in all three parameters, while rCBF helped to distinguish between chronic focal epilepsies and single events. CONCLUSION: Preliminary results indicate that P-CT may help to identify patients with SSE during emergency workup. This technique provides important information to neurologists or emergency physicians in the difficult clinical differential diagnosis of altered mental status due to subtle status epilepticus.

Adult↗

PubMed2006

A novel multiple-trauma CT-scanning protocol using patient repositioning.

Emergency CT examination is considered to be a trade-off between a short scan time and the acceptance of artifacts. This study evaluates the influence of patient repositioning on artifacts and scan time. Eighty-three consecutive multiple-trauma patients were included in this prospective study. Patients were examined without repositioning (group 1, n=39) or with patient rotation to feet-first with arms raised for scanning the chest and abdomen/pelvis (group 2, n=44). The mean scan time was 21 min in group 1 and 25 min in group 2 (P=0.01). The mean repositioning time in group 2 was 8 min. Significantly, more artifacts were observed in group 1 (with a repeated scan in 7%) than in group 2 (P=0.0001). This novel multiple- trauma CT-scanning protocol with patient repositioning achieves a higher image quality with significantly fewer artifacts than without repositioning but increases scan time slightly.

Adolescent↗

PubMed2006

Forensic veterinary radiology: ballistic-radiological 3D computertomographic reconstruction of an illegal lynx shooting in Switzerland.

The lynx, which was reintroduced to Switzerland after being exterminated at the beginning of the 20th century, is protected by Swiss law. However, poaching occurs from time to time, which makes criminal investigations necessary. In the presented case, an illegally shot lynx was examined by conventional plane radiography and three-dimensional multislice computertomography (3D MSCT), of which the latter yielded superior results with respect to documentation and reconstruction of the inflicted gunshot wounds. We believe that 3D MSCT, already described in human forensic-pathological cases, is also a suitable and promising new technique for veterinary pathology.

Animals↗

PubMed2006

Changes in the volume and density of calvarial split bone grafts after alveolar ridge augmentation.

OBJECTIVES: One main problem occurring after bone grafting is resorption, leading to insufficient bone volume and quality, and may subsequently cause dental implant failure. Comparison of graft volume and bone density of iliac crest and calvarial transplants determined by animal studies demonstrates significantly lower resorption of bone grafts harvested from the skull. This paper is the first clinical study evaluating bone volume and density changes of calvarial split bone grafts after alveolar ridge reconstruction. MATERIAL AND METHODS: Bone volume and density were determined using CT scans and the software program Dicom Works in a total of 51 calvarial grafts after alveolar ridge augmentation in 15 patients. CT scans were taken in all 15 patients immediately after grafting (T0) and before implantation after a postoperative period of 6 months (T1). In five patients (26 calvarial grafts), a 1-year follow-up was performed (T2). RESULTS: A mean volume reduction of 16.2% at T1 (15 patients) and 19.2% at T2 (five patients) was observed. Bone density was high--about 1000 Hounsfield units--and did not change during the 1-year period. At the time of implantation, 41 transplants were classified as quality 1 bone and 10 as quality 2-3 bone. Grafting area and the technique used for grafting (inlay or onlay graft) did not affect the postoperative bone volume reduction. Generalized osteoporosis did not increase the resorption rate of calvarial transplants. CONCLUSION: Based on these findings, calvarial split bone grafts are a promising alternative for alveolar ridge reconstruction in dental implantology.

Adolescent↗

PubMed2006

Fabry's disease: otoneurologic findings in twelve members of one family.

Fabry's disease corresponds to an inherited disorder transmitted by an X-linked recessive gene. It generates a dysfunction of glycosphingolipid metabolism due to an enzymatic deficiency of alpha-galactosidase activity, resulting in glycosphingolipid deposits in all areas of the body. The clinical (heart, kidney, and central nervous system) manifestations are more severe in hemizygous boys than in heterozygous girls. They appear during childhood or adolescence: acroparesthesia, joint pain, angiokeratoma, corneal dystrophy, hypohydrosis or anhydrosis, and renal failure. The otoneurologic symptoms consist of hearing fluctuation, progressive unilateral or bilateral hearing loss, and episodes of vertigo or dizziness. Otoneurologic findings in 12 of 26 members of the same family are presented: the mother and 9 of her 12 children, as well as 2 of her 14 grandchildren: 4 healthy persons, 4 heterozygous female carriers, and 4 hemizygous male patients. Three of the male patients had fluctuation of hearing, sudden hearing loss, and episodes of vertigo and dizziness. The otoneurologic examinations showed a bilateral cochleovestibular deficit (n = 1), a right cochleovestibular deficit (n = 1), and a bilateral hearing loss combined with a right vestibular deficit (n = 1). Histopathologic evidence of glycosphingolipid accumulation in vascular endothelial and ganglion cells, as well as atrophy of the stria and spiral ligament, might explain the otoneurologic symptoms and findings.

Adult↗

PubMed2005

Internal carotid artery stent implantation in 25 patients with acute stroke: preliminary results.

PURPOSE: To evaluate retrospectively the outcome for patients with acute ischemic stroke in the territory of the middle cerebral artery (MCA) who had undergone stent implantation in the proximal segment of the internal carotid artery (ICA) in addition to intraarterial thrombolysis (IAT). MATERIALS AND METHODS: Stent implantation and retrospective analysis of clinical and radiologic data were approved by the institutional ethical committee. Endovascular treatment was performed after obtaining informed consent from patients or their closest relatives. Informed consent for retrospective review was not required. After pharmacologic and/or mechanical IAT, 25 consecutive patients (seven women, 18 men; mean age, 59 years +/- 14 [standard deviation]) underwent stent implantation in the proximal segment of the ICA (endovascular group). The clinical and radiologic characteristics (ie, interval from symptom onset to arrival at the emergency department, prevalence of vascular risk factors, causes of stroke, stroke severity, early signs of cerebral ischemia, duration of endovascular intervention, type of occlusion, and prevalence of leptomeningeal collateral vessels), recanalization rates, and clinical outcomes for patients in the endovascular group were compared with those for patients in the medical group (10 women, 21 men; mean age, 62 years +/- 12) who experienced ischemic stroke in the territory of the MCA as a result of ICA occlusion and who received antithrombotic treatment only. Differences between groups were assessed by using the chi2 test. A logistic regression analysis was performed to assess the effect of clinical and radiologic factors on recanalization rates and outcome. RESULTS: ICA recanalization was successful in 21 patients. Good recanalization of the MCA was achieved in 11 patients. In nine of these patients, recanalization of the MCA was achieved by using mechanical IAT only. In the remaining 12 patients, administration of intraarterial urokinase was performed in addition to mechanical thrombolysis. Two patients from the endovascular group experienced symptomatic intracerebral hemorrhage. At 3 months, 56% of the endovascular group and 26% of the medical group had a favorable outcome. Mortality was 20% in the endovascular and 16% in the medical group. CONCLUSION: IAT and stent implantation in the proximal segment of the ICA seem to improve the outcome for patients with ischemic stroke caused by occlusion of the cervical portion of the ICA.

Acute Disease↗

PubMed2005

Endovascular neuroradiological treatment of acute ischemic stroke: techniques and results in 350 patients.

BACKGROUND AND OBJECTIVES: Randomized trials have demonstrated the benefit of intra-arterial thrombolysis (IAT) for treatment of acute ischemic stroke, if performed within 6 hours of symptom onset. METHODS: We report our experience with 350 acute stroke patients who were treated with IAT using urokinase at a single center. Predictors of favorable outcome were low National Institute of Health Stroke Scale (NIHSS) at admission (p<0.001), good collaterals (p<0.001) and successful endovascular recanalization (p<0.001). Recanalization rates of more than 75% could be achieved, when additional endovascular techniques such as mechanical fragmentation of the thrombus, thromboaspiration, percutaneous transluminal angioplasty, and implantation of stents were used. RESULTS AND CONCLUSIONS: Predictors of unfavorable outcome were diabetes mellitus (p<0.001) and symptomatic hemorrhages (p<0.001). The latter occurred in 5% of our population. Preliminary results of new techniques including sonothrombolysis, angiojet aspiration, and laser recanalization of thromboembolic occlusions are discussed.

Basilar Artery↗

PubMed2005

Evaluation of a 16-MDCT scanner in an emergency department: initial clinical experience and workflow analysis.

OBJECTIVE: MDCT is especially suited for emergency purposes because it allows rapid high-resolution scans of large areas, fast high-quality reformatting in every orientation, and 3D illustration of the data set. In a prospective study, we evaluated the reliability and workflow of a dedicated emergency department 16-MDCT scanner in the management of patients presenting to the emergency department. SUBJECTS AND METHODS: The use of a 16-MDCT scanner for 503 patients in the emergency department of a university clinic was evaluated. For reasons of workflow analysis, seven precise time intervals were recorded during the emergency examinations. A new setting for repositioning multiple-trauma patients after imaging of the head and neck from the head-first position to the feet-first position was introduced. RESULTS: Six (1.2%) of the 503 patients were excluded because of technical malfunction or patient noncompliance. Image quality in the remaining 497 cases, including CT angiography and CT of multiple-trauma patients, was outstanding. Positioning of the patients took from 3 to 13 min depending on the body region examined, representing 33-67% of the mean room time, which ranged from 8 to 21 min. In multiple-trauma patients, the initial positioning took a mean of 6 min and repositioning took 8 min, representing 19% and 26% of total room time, respectively. CONCLUSION: The use of a dedicated 16-MDCT scanner in the emergency department resulted in short examination times even for examinations of multiple body regions under emergency conditions. The introduced setting-repositioning of multiple-trauma patients-allowed high image quality to be maintained. The trade-off in multiple-trauma patients was prolonged room time because of patient repositioning.

Efficiency, Organizational↗

PubMed2004

The amygdala in schizophrenia: a trimodal magnetic resonance imaging study.

In schizophrenic psychoses, structural and functional alterations of the amygdala have been demonstrated by several neuroimaging studies. However, postmortem examinations on the brains of schizophrenics did not confirm the volume changes reported by volumetric magnetic resonance imaging (MRI) studies. In order to address these contradictory findings and to further elucidate the possibly underlying pathophysiological process of the amygdala, we employed a trimodal MRI design including high-resolution volumetry, diffusion tensor imaging (DTI), and quantitative magnetization transfer imaging (qMTI) in a sample of 14 schizophrenic patients and 14 matched controls. Three-dimensional MRI volumetry revealed a significant reduction of amygdala raw volumes in the patient group, while amygdala volumes normalized for intracranial volume did not differ between the two groups. The regional diffusional anisotropy of the amygdala, expressed as inter-voxel coherence (COH), showed a marked and significant reduction in schizophrenics. Assessment of qMTI parameters yielded significant group differences for the T2 time of the bound proton pool and the T1 time of the free proton pool, while the semi-quantitative magnetization transfer ratio (MTR) did not differ between the groups. The application of multimodal MRI protocols is diagnostically relevant for the differentiation between schizophrenic patients and controls and provides a new strategy for the detection and characterization of subtle structural alterations in defined regions of the living brain.

Adult↗

PubMed2004

Virtopsy post-mortem multi-slice computed tomography (MSCT) and magnetic resonance imaging (MRI) demonstrating descending tonsillar herniation: comparison to clinical studies.

Descending cerebellar tonsillar herniation is a serious and common complication of intracranial mass lesions. We documented three cases of fatal blunt head injury using post-mortem multi-slice computed tomography (MSCT) and magnetic resonance imaging (MRI). The results showed massive bone and soft-tissue injuries of the head and signs of high intracranial pressure with herniation of the cerebellar tonsils. The diagnosis of tonsillar herniation by post-mortem radiological examination was performed prior to autopsy. This paper describes the detailed retrospective evaluation of the position of the cerebellar tonsils in post-mortem imaging in comparison to clinical studies.

Adult↗

PubMed2004

Transdermal nitroglycerin in patients with subarachnoid hemorrhage.

Delayed ischemic neurological deficit (DIND) following cerebral vasospasm remains a cause for high morbidity and mortality in patients with subarachnoid hemorrhage (SAH). There is experimental and clinical evidence of positive effects of nitric oxide (NO) donors on cerebral vasospasm. We therefore analysed the effect of transdermal nitroglycerin in patients with SAH measuring transcranial Doppler velocities (TCD), cerebral blood flow (CBF) and DIND. Nitroglycerin was used in a target dose of 14 microg/kg/h. TCD assessment was performed daily. CBF measurements were done using the perfusion CT-technique. Blood pressure, volume intake and vasopressor administration, were registered. Nine patients were randomly assigned either to the nitroglycerin group (N-group) and eight patients in the control group (C-group). Mean TCD values in the extracranial portion of the internal carotid artery (ICA) were lower in the N-group (p<0.005). Mean TCD in the middle cerebral arteries (MCA) showed no difference. The Lindegaard ratio was higher in the N-group (p<0.04). CBF in the N-group was higher than in the C-group (p<0.03). Even though nitroglycerin reduces blood pressure and lowers ICA TCD-values and increases the Lindegaard ratio, a higher CBF was measured in the N-group. Thus, nitroglycerin influences the cerebral vascular tone and increases CBF. SAH therapy with nitroglycerin is possible without increasing the risk of DIND. The exact timing of onset, duration and reduction of nitroglycerin administration in respect to the appearance of vasospasm may have a strong impact on the success of such a therapy.

Administration, Cutaneous↗

PubMed2004

Esthesioneuroblastoma of the pituitary gland: a clinicopathological entity? Case report and review of the literature.

Esthesioneuroblastoma (olfactory neuroblastoma) is a rare, malignant neoplasm that typically arises in the nasal vault, invades adjacent tissues, and causes locoregional (cervical lymph nodes) and distant metastases. Only two cases of tumors arising in the sellar region that had the histological characteristics of esthesioneuroblastoma have been reported in the literature to date. The authors present the case of a 35-year-old woman with secondary amenorrhea and a rapidly growing tumor located in the adenohypophysis. After total removal of the lesion through a transseptal-transsphenoidal approach, the histological examination revealed an esthesioneuroblastoma Grade II/III according to Hyams. Considering the particular location of the lesion and the absence of residual tumor on postoperative magnetic resonance imaging, no adjuvant therapy was performed. The patient remained free from tumor recurrence 2 years postoperatively. Because all published cases of this esthestoneuroblastoma have been large neuroblastic tumors of the pituitary gland arising in middle-aged women, pituitary neuroblastoma might represent a rare, specific clinicopathological entity.

Adult↗

PubMed2003

Image-guided virtual autopsy findings of gunshot victims performed with multi-slice computed tomography and magnetic resonance imaging and subsequent correlation between radiology and autopsy findings.

Because the use of radiology in modern forensic medicine has been, until today, mostly restricted to conventional X-rays, which reduces a 3D body to a 2D projection, a detailed 3D documentation of a gunshot's wound ballistic effects was not possible. The aim of our study was to evaluate whether the progress in imaging techniques over the last years has made it possible to establish an observer-independent and reproducible forensic assessment using multi-slice computed tomography (MSCT) and magnetic resonance imaging (MRI) technologies for the documentation and analysis of gunshot wounds. The bodies of eight gunshot victims were scanned by MSCT and by MRI; the data of these imaging techniques were post-processed on a workstation, interpreted and subsequently correlated with the findings of classical autopsy. With the spiral CT and MRI examinations and the subsequent 2D multi-planar reformation (MPR) and 3D shaded surface display (SSD) reconstruction, the entire gunshot-created complex skull fractures and brain injuries (such as wound channels and deeply-driven bone splinters) could be documented in complete and graphic detail. CT and MRI also documented vital reaction to the gunshot by demonstrating air emboli in the heart and blood vessels and the classic pattern of blood aspiration to the lung. Gunshot residues deposited within and under the skin were visible. In conclusion, we think that the radiological methods of MSCT and MRI have the potential to become a routine "virtual autopsy" tool in the future. Bullets and relevant histological samples from specific sites then might be won in image-guided minimally invasive fashion via percutaneous biopsy. The rapid application of developing radiological methods may lead to new horizons in forensic documentation and intravital as well as postmortem examination.

Autopsy↗

PubMed2003

New horizons in forensic radiology: the 60-second digital autopsy-full-body examination of a gunshot victim by multislice computed tomography.

The goal of this study was the full-body documentation of a gunshot wound victim with multislice helical computed tomography for subsequent comparison with the findings of the standard forensic autopsy. Complete volume data of the head, neck, and trunk were acquired by use of two acquisitions of less than 1 minute of total scanning time. Subsequent two-dimensional multiplanar reformations and three-dimensional shaded surface display reconstructions helped document the gunshot-created skull fractures and brain injuries, including the wound track, and the intracerebral bone fragments. Computed tomography also demonstrated intracardiac air embolism and pulmonary aspiration of blood resulting from bullet wound-related trauma. The "digital autopsy," even when postprocessing time was added, was more rapid than the classic forensic autopsy and, based on the nondestructive approach, offered certain advantages in comparison with the forensic autopsy.

Autopsy↗

PubMed2003

Virtopsy, a new imaging horizon in forensic pathology: virtual autopsy by postmortem multislice computed tomography (MSCT) and magnetic resonance imaging (MRI)--a feasibility study.

Using postmortem multislice computed tomography (MSCT) and magnetic resonance imaging (MRI), 40 forensic cases were examined and findings were verified by subsequent autopsy. Results were classified as follows: (I) cause of death, (II) relevant traumatological and pathological findings, (III) vital reactions, (IV) reconstruction of injuries, (V) visualization. In these 40 forensic cases, 47 partly combined causes of death were diagnosed at autopsy, 26 (55%) causes of death were found independently using only radiological image data. Radiology was superior to autopsy in revealing certain cases of cranial, skeletal, or tissue trauma. Some forensic vital reactions were diagnosed equally well or better using MSCT/MRI. Radiological imaging techniques are particularly beneficial for reconstruction and visualization of forensic cases, including the opportunity to use the data for expert witness reports, teaching, quality control, and telemedical consultation. These preliminary results, based on the concept of "virtopsy," are promising enough to introduce and evaluate these radiological techniques in forensic medicine.

Adolescent↗

PubMed2002

Non-traumatic neurological emergencies: emergency neuroradiological interventions.

This article summarizes recent developments in the growing field of interventional neuroradiology for the treatment of acute cerebrovascular disease. We describe the possibilities in endovascular therapy of acute cerebral aneurysms using electrolytically detachable coils combined with trispan neck bridging devices and stent implantation to occlude acute wide neck aneurysms. Techniques and results of local intra-arterial thrombolytic therapy in acute stroke and central retinal artery occlusion are described and we discuss the potential for rapid, large-burden thrombus removal in cases of internal carotid artery thrombosis by rheolytic thrombectomy, percutaneous transluminal angioplasty and stent implantation. Emergency endovascular therapy using the transvenous approach to treat severe intracranial or intraocular hypertension and multifocal haemorrhagic venous infarction due to cerebral sinus thrombosis or dural fistulas is also described. In cases of acute bleeding of head and neck lesions following trauma, tumours after radiotherapy, arteriovenous malformations, epistaxis or from iatrogenic origin, angiography plays a major role in localizing the source of bleeding and occluding the damaged vessel during the same session using the same endovascular approach.

Adolescent↗

PubMed2002

Charred body: virtual autopsy with multi-slice computed tomography and magnetic resonance imaging.

The correct examination of a charred body is a forensic challenge. Examination, interpretation, and conclusion in respect to identification, vital reactions, toxicological analysis, and determining cause and manner of death are all more difficult than without burns. To evaluate what can be seen in the case of a charred body, we made an examination with the new radiological modalities of cross-section techniques, via multi-slice Computed Tomography (MSCT) and Magnetic Resonance Imaging (MRI), prior to performing the classical forensic autopsy. In a charred body case of a single motor vehicle/fixed object collision with a post crash fire, the radiological methods of MSCT and MRI made it possible to document the injuries caused by burn as well as the forensic relevant vital reactions (air embolism and blood aspiration). In conclusion, we think postmortem imaging is a good forensic visualization tool with a great potential for the forensic documentation and examination of charred bodies.

Autopsy↗