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J P Schneider

Publications and source records attributed to J P Schneider.

At least 19 recordsLinked to original sources
PubMed2006

[Cerebral lesions in acute arterial hypertension: the characteristic MRI in hypertensive encephalopathy].

PURPOSE: In the nine years since the posterior reversible (leuc) encephalopathy syndrome (PRES) was first described, a number of causes have been under discussion. These not only include arterial hypertension, i. e. hypertensive crises, but also various toxic substances, i. e. immunosuppressive or chemotherapeutic agents, that are responsible for the formation of the symptoms and characteristic MR tomographic brain findings. MATERIALS AND METHODS: Initial and follow-up MRI examinations of 8 patients were analyzed. All patients had acute neurological symptoms (headaches, seizures, visual disorders and vigilance disturbances) together with a detectable hypertensive crisis. RESULTS: MRI disclosed increased signal intensity in subcortical and some cortical lesions in all patient FLAIR sequences. These changes were particularly extensive in the posterior circulation (occipital, cerebellum and brain stem) although they were also detected in brain areas supplied by the carotid artery. However, a cytotoxic genesis of the changes was ruled out in each patient by means of a normal DWI. Furthermore, when the blood pressure was normalized, reversibility of the lesions as proof of the diagnosis was detectable. CONCLUSION: The imaging findings can be typically analyzed as a predominantly posterior distribution of encephalopathic lesions with a high probability of reversibility after lowering blood pressure was patients suffering from a critical increase in blood pressure with corresponding neurological symptoms. The exact pathophysiology remains unclear, but the cause currently most favored is a vasculopathy of the posterior circulation due to diminished adrenergic autoregulation in combination with a dysfunction of the endothelial cells. In conclusion, we suggest designating this subpopulation from the non-uniform pool of patients with posterior (leuc) encephalopathy as "hypertensive encephalopathy". "Hypertensive encephalopathy" has to be distinguished from "toxic encephalopathy", particularly due to different therapeutic and prognostic consequences.

Adult↗
PubMed2006

Profound midbrain atrophy in patients with Wilson's disease and neurological symptoms?

Wilson's disease (WD) is characterized by impaired hepatic copper secretion and subsequent copper accumulation in many organs predominantly liver and brain, secondary to loss of function mutations in the copper transport protein ATP7B. If the disease is recognized too late or treatment is not adequate, brain copper accumulation leads to progressive neurodegeneration with a variety of clinical symptoms. The nigrostriatal dopaminergic system seems rather vulnerable. Midbrain atrophy, however, has not been recognized as one of the prime features of patients with WD. Here we report quantification of midbrain diameter in 41 patients with WD. Data were correlated to the severity of neurological symptoms and the integrity of dopaminergic neurons measured via dopamine transporter binding. For control, we measured midbrain diameter in 18 patients with no evidence for brainstem dysfunction and 5 patients with progressive supranuclear palsy (PSP). Patients with WD had a reduced midbrain diameter (15.5 +/- 0.4 mm) compared to controls (18.5 +/- 0.2 mm). WD patients without neurological symptoms had midbrain diameter that were not different from controls (18.0 +/- 0.3 mm), while patients with neurological symptoms showed midbrain atrophy similar to patients with PSP (14.4 +/- 0.3 mm versus 14.1 +/- 0.3). There was a strong and significant correlation between midbrain atrophy and the severity of neurological symptoms (r= -0.68, p < 0.001) while midbrain atrophy and dopamine transporter binding correlated significantly but was less pronounced (r=0.46, p < 0.001). In summary, we were able to show, that midbrain diameter is an easy to perform quantification of neurodegeneration induced by brain copper accumulation and that other structures than substantia nigra dopaminergic neurons seem to contribute to midbrain atrophy in WD.

Adult↗
PubMed2006

[Correlation of clinical aspects as well as genotype and phenotype in Wilson's disease on the basis of epidemiologic, clinical and cranial MRI findings].

Wilson's disease, a rare autosomal recessive disorder of hepatic copper transport, is characterized by a varying pattern of hepatic, neurologic and psychiatric symptoms. Currently, about 250 causative mutations of the ATP 7B gene are known. However, a correlation between genotype and phenotype according to these mutations is not yet clear. To elucidate a possible correlation in this study 39 patients with Wilson's disease were subdivided into three groups according to the underlying mutation in group I for homocygote respectively group II for compound heterocygote mutation in H1069Q and group III for other mutations. Clinical subtype and extent of neurologic disturbance as well as epidemiologic aspects, presence of psychiatric symptoms, results of acustically evoked potentials (Wave III, interpeak latency III-V) and findings of cranial MRI were considered. While psychopathological symptoms, the results of acustically evoked potentials and cranial MRI show a correlation to the clinical subtype of Wilson's disease there was no genotype-phenotype correlation on the basis of the mutation in H1069Q. The qualitative and quantitative pattern of results do not show any significant differences in the three groups of genotype. Thus, the time of treatment onset still has most influence on the extent of clinical manifestation and reversibility of the toxic copper accumulation.

Adenosine Triphosphatases↗
PubMed2005

Pediatric MR-guided interventions.

MRI guided interventions are a relatively new but steadily growing field within surgery in pediatric age. Besides the advantages of MRI, such as multiplanar capability and excellent soft tissue contrast and spatial resolution, particularly relevant for the pediatric population is the lack of ionizing radiation. There is meanwhile a group of well defined diagnostic or therapeutic indications for applying MR imaging during pediatric interventions. Aim of this review is to give an overview about indications of MR-guided procedures in children as well as the advantages and disadvantages of MR-guided interventions. We also briefly discuss interventional MR-systems and MR-compatible devices. It is our opinion that MR-guidance for pediatric interventions is a promising technique at the beginning of its development.

Child↗
PubMed2005

Movement of the upper cervical spine during laryngoscopy: a comparison of the Bonfils intubation fibrescope and the Macintosh laryngoscope.

The movements of the upper cervical spine were measured by fluoroscopy in 20 patients during laryngoscopy with the Bonfils intubation fibrescope and the Macintosh laryngoscope. Laryngoscopy with both the Bonfils intubation fibrescope and the Macintosh laryngoscope resulted in significant extension of the cervical spine as compared to the neutral position but this extension was significantly less with the Bonfils intubation fibrescope than with the Macintosh (p = 0.001). However, the atlanto-occipital distance was significantly greater during laryngoscopy with the Bonfils intubation fibrescope (p = 0.002), and the angle between the occiput and C1 differed significantly between the two techniques (p = 0.001). With the Bonfils intubation fibrescope, significantly less extension was also found at the C1/C2 and C3/C4 levels (p = 0.001 and p = 0.049, respectively). There is therefore significantly less movement of the upper cervical spine during laryngoscopy with the Bonfils fibrescope compared with the Macintosh laryngoscope.

Adult↗
PubMed2005

Evaluation of intra-operative ultrasound imaging in brain tumor resection: a prospective study.

AIMS: The purpose of our study was to evaluate intra-operative ultrasound (IOUS) as a tool of resection control after brain tumor surgery. In addition, we looked for tumor species suitable for ultrasound representation. METHODS: Using a Siemens Omnia Sonoline Ultrasound, 36 tumors were examined, high-grade gliomas (62%), metastases (22%) and others (16%). We focused on tumor imaging by ultrasound with regard to its reliability of tumor expansion and margins. Evaluation of the images was carried out by correlating the ultrasound-based intra-operative measured tumor volume before and after resection with a pre- and post-operative (within 48 hours) measured volume by MRI. The IOUS measurements were performed by the neurosurgeon and the MRI measurements by the neuroradiologist. Thus, the measurement procedures were blinded. Corresponding to a deviation of the ultrasound volume by 10, 20 and > 20% from the MRI volume, the correlation was ranked good, moderate and poor. For assessing the agreement between these two methods of imaging, the statistical analysis was conducted using a method described by Bland and Altman. RESULTS: High-grade gliomas mostly showed a moderate or poor correlation in comparing IOUS- and MRI-tumor volumetry resulting in incomplete resection. Metastases resulted in a good to moderate correlation with a satisfactory extent of resection. The other tumors had poor images with larger tumor residues. The MRI measured volumes tended to be larger on average; the deviation grew with tumor size . CONCLUSION: The reliability of IOUS depends on tumor type. It is beneficial to use IOUS for the resection of metastases and a few high-grade gliomas. Concerning the volumetric accuracy, the value of IOUS is worse than its value of navigation and resection control.

Adolescent↗
PubMed2004

Laser-induced thermotherapy of neoplastic lesions in the brain--underlying tissue alterations, MRI-monitoring and clinical applicability.

Laser-induced thermotherapy (LITT) is a minimally invasive neurosurgical approach to the stereotactic treatment of brain tumors in poorly accessible regions. Its clinical applicability has been shown in several experimental and clinical studies under on-line monitoring by magnetic resonance imaging (MRI). This review characterizes LITT as an alternative neurosurgical approach with specific focus on the typical histological alterations and ultrastructural cellular changes following laser irradiation in the central nervous system. The spatial and temporal pattern of these changes is discussed in their relevance to the neurosurgical treatment of neoplastic lesions using LITT.

Aged↗
PubMed2004

Fatal bihemispheric intracerebral hemorrhage after burrhole evacuation of chronic subdural hematoma in a bone marrow-transplanted patient: case report and review of the literature.

BACKGROUND: Intracranial hemorrhage seems to be a relatively frequent complication following bone marrow transplantation (BMT). The neurosurgical management of these patients can be problematic. CASE DESCRIPTION: We report about a 46-year-old patient, who had BMT because of a Pre-T-ALL and who developed symptomatic bihemispheric chronic subdural hematomas (cSDHs). Pre-T-ALL is a form of an acute lymphatic leukemia of T cell type characterized by certain immunologic markers with a worse prognosis. A few hours after evacuation of the cSDHs, the patient developed a fulminant intracerebral hemorrhage on each hemisphere and expired 2 days later. We reviewed the literature reporting similar cases to discuss the indication for a neurosurgical intervention. CONCLUSION: We presume a higher incidence of intracranial hemorrhage in BMT patients than reported. This is caused by the pathologically altered parenchyma related to the extensive therapy in these patients. BMT patients are typically at high risk for intracranial bleeding and are treated conservatively or surgically. We cannot generally recommend the conservative management for symptomatic subdural hematomas/hygromas. The risk for an acute worsening, secondary to repeated hemorrhage, is equivalent to the risk of surgical intervention. Although the outcome of our case is tragic, it should not deter surgical intervention.

Bone Marrow Transplantation↗
PubMed2004

[First clinical experience with extended planning and navigation in an interventional MRI unit].

PURPOSE: To present an advanced concept for patient-based navigation and to report on our first clinical experience with interventions in the cranium, of soft-tissue structures (breast, liver) and in the musculoskeletal system. MATERIALS AND METHODS: A PC-based navigation system was integrated into an existing interventional MRI environment. Intraoperatively acquired 3D data were used for interventional planning. The information content of these reference data was increased by integration of additional image modalities (e. g., fMRI, CT) and by color display of areas with early contrast media enhancement. Within 18 months, the system was used in 123 patients undergoing interventions in different anatomic regions (brain: 64, paranasal sinus: 9, breast: 20, liver: 17, bone: 9, muscle: 4). The mean duration of 64 brain interventions was compared with that of 36 procedures using the scanner's standard navigation. RESULTS: In contrast with the continuous scanning mode of the MR system (0.25 fps), the higher quality as well as the real time display (4 fps) of the MR images reconstructed from the 3D reference data allowed adequate hand-eye coordination. With our system, patient movement and tissue shifts could be immediately detected intraoperatively, and, in contrast to the standard procedure, navigation safely resumed after updating the reference data. The navigation system was characterized by good stability, efficient system integration and easy usability. Despite additional working steps still to be optimized, the duration of the image-guided brain tumor resections was not significantly longer. CONCLUSION: The presented system combines the advantage of intraoperative MRI with established visualization, planning, and real time capabilities of neuronavigation and can be efficiently applied in a broad range of non-neurosurgical interventions.

Bone and Bones↗
PubMed2003

Clinical results in MR-guided therapy for malignant gliomas.

The prognostic impact of the extent of tumour resection in surgery of malignant glioma patients remains controversial. We report the results of cumulative survival of malignant glioma patients operated with MR-guidance. Patients with complete tumour removal were compared with a population of patients with incomplete tumour removal. A 0.5 T scanner was used to criticize the extent of resection during surgery. In total no significant difference could be found, however there is a tendency that complete tumour removal seems to be associated with a slightly increased median survival time.

Adult↗
PubMed2003

[MRI-guided pediatric interventions].

AIM: There are only a few diagnostic or therapeutic procedures where MR imaging is applied during pediatric interventions. This study will describe indications, complications as well as the advantages and disadvantages of MRI-guided interventions based on a case study in an open MRI scanner. MATERIALS AND METHODS: 14 procedures were performed in an open MRI scanner (Signa SP/i, GEMS) on 13 children (1 - 16 yr) with bone, soft tissue and brain lesions (1 - 4 cm diameter). Localization of the pathology, targeting and final control of the result were based on images acquired with SE-, 3D-, GE-sequences pre- and post-contrast as well as FSE-sequences. Interactive MRI-guided instrument navigation was performed using a multiplanar T1w GE-sequence. RESULTS: Eight biopsies (incl. 1 rebiopsy), two tumor resections, one removal of a free joint mouse and three tumor-markings were performed without complications. Five biopsies provided appropriate sample quality for a histological diagnosis while two samples were too fragmented requiring a second biopsy (one of them MRI-guided). Surgical progress during tumor resection and marking could be controlled during the intervention without repositioning the patient. DISCUSSION: MR image guided pediatric interventions combine the advantage of an imaging system without ionizing radiation and the high soft-tissue contrast. The low number of these kinds of procedures can be explained by the relatively high costs for the intervention, the increased duration for each procedure and the limited availability of open MRI systems. The integrated localization-system helps during planning of the access path when facing complex anatomical structures and provides safe navigation in sensitive regions like the epiphyseal cartilage. Recent and expected developments of the required MR-compatible biopsy instruments could provide higher efficiency for appropriate sample size and quality. Summarizing, MRI-guided pediatric interventions have shown to be a promising method at the beginning of its development.

Adolescent↗
PubMed2002

[MR-guided preoperative localization and percutaneous core biopsy of suspected breast lesions. Possibilities and experience on the vertically open 0.5-T-system].

PURPOSE: To evaluate the feasibility of performing breast interventions in a vertically open 0.5 T MR system (SIGNA SP/i, GE Medical Systems). To develop fitted equipment and to establish preoperative wire localization and percutaneous breast core biopsy as clinical routine procedures. PATIENTS AND METHODS: Initially, we applied a localization method with the patient placed in a sitting position in 31 cases using a single loop coil and a self-developed fixation device. Subsequently, 46 wire localizations and 28 percutaneous core biopsies were carried out in prone patient position using an open breast coil with an integrated biopsy device. The used instruments were either MR-compatible (18 G biopsy needle and localization wire, 14 G coaxial needle, prototype of a 16 G double-shoot gun) or MR-safe (double-shoot gun with 16 G needle). RESULTS: After biopsy we found the needle tip (18 G for a wire localization and 14 G for a percutaneous core biopsy, respectively) placed either within or close to the lesions (< 10 mm distance) for all patients. Out of a total of 66 benign lesions and 39 malignant tumors we missed the lesion (12 mm mean diameter, 4-25 mm range) during open biopsy in two cases and obtained a false negative result for one percutaneous biopsy of a 5 mm lesion. CONCLUSION: Preoperative wire localization and percutaneous core biopsy of suspicious breast lesions demonstrated by MRI can be carried out a vertically open 0.5 T MR scanner. The degree of accuracy is comparable with that of X-ray or ultrasound-guided procedures. A follow-up has to be performed in cases with a negative biopsy.

Adult↗
PubMed2001

beta-blockers before percutaneous coronary intervention do not attenuate postprocedural creatine kinase isoenzyme rise.

BACKGROUND: beta-blocker (BB) use reduces infarct size in spontaneously occurring nonreperfused infarcts but probably does not change infarct size in patients treated with reperfusion therapy. A recent observational study suggested that BB use concurrent with percutaneous coronary intervention (PCI) decreased the risk of creatine kinase (CK)-MB elevation. The cogency of such a conclusion is dependent on the ability to risk-adjust for the multiple differences in patients treated with and without BBs. METHODS AND RESULTS: Using propensity score and multivariate regression analyses, 6200 consecutive patients were analyzed to assess the relationship between BB use before PCI and per protocol-measured CK and CK-MB rise. There were several highly significant (P<0.001) differences between patients with and without BB treatment (eg, age, prior infarction, unstable angina). Maximum CK and CK-MB levels were higher in patients taking BBs (CK median, 95 U [interquartile range: 61, 175]; CK-MB, 3 U [2, 5]) than in patients not taking BBs (CK, 91 U [60, 157]; CK-MB, 3 U [2, 4]) (P=0.011 and P=0.021 for CK and CK-MB, respectively). After adjustment for significant differences in baseline characteristics there was no difference in either maximum CK rise (P=0.21) or maximum CK-MB rise (P=0.99). CONCLUSIONS: The results of this large observation study do not support the contention that BB use before PCI decreases myocardial injury.

Adrenergic beta-Antagonists↗
PubMed2001

Incremental prognostic value of elevated baseline C-reactive protein among established markers of risk in percutaneous coronary intervention.

BACKGROUND: Established methods of risk assessment in percutaneous coronary intervention have focused on clinical and anatomical lesion characteristics. Emerging evidence indicates the substantial contribution of inflammatory processes to short-term and long-term outcomes in coronary artery disease. METHODS AND RESULTS: Within a single-center registry of contemporary percutaneous coronary revascularization strategies with postprocedural creatine kinase and clinical events routinely recorded, we assessed the association of baseline C-reactive protein with death or myocardial infarction within the first 30 days. Predictive usefulness of baseline C-reactive protein within the context of established clinical and angiographic predictors of risk was also examined. Among 727 consecutive patients, elevated baseline C-reactive protein before percutaneous coronary intervention was associated with progressive increase in death or myocardial infarction at 30 days (lowest quartile, 3.9%, versus highest quartile, 14.2%; P=0.002). Among clinical and procedural characteristics, baseline C-reactive protein remained independently predictive of adverse events, with the highest quartile of C-reactive protein associated with an odds ratio for excess 30-day death or myocardial infarction of 3.68 (95% CI, 1.51 to 8.99; P=0.004). A predictive model that included baseline C-reactive protein quartiles, American College of Cardiology/American Heart Association lesion score, acute coronary syndrome presentation, and coronary stenting appears strongly predictive of 30-day death or myocardial infarction within this population (C-statistic, 0.735) and among individual patients (Brier score, 0.006). CONCLUSIONS: Elevated baseline C-reactive protein portends heightened risk of 30-day death or myocardial infarction after coronary intervention. Coupled anatomic, clinical, and inflammatory risk stratification demonstrates strong predictive utility among patients undergoing percutaneous coronary intervention and may be useful for guiding future strategies.

Aged↗
PubMed2001

Transnasal and transsphenoidal MRI-guided biopsies of petroclival tumors.

Magnetic resonance imaging (MRI) allows excellent tissue characterization in the area of the petroclival region and can depict lesions not visualized with ultrasound or computed tomography (CT). The aim of this study was to demonstrate the clinical feasibility and utility of an interactive MR-guidance system to target and biopsy tumors in the petroclival region. MRI-guided biopsies of 10 patients with tumors in the clivus and petrous apex were performed in an open 0.5-T MR system. Lesions were targeted through a transsphenoidal or transnasal approach. Imaging during biopsies was achieved by a combination of standard and interactive mode. T1-weighted spin-echo, T2-weighted fast spin-echo (FSE), and three-dimensional T1-weighted gradient-echo (GRE) scans (standard mode) were selected to provide optimal tissue characterization for both the lesion and surrounding structures and varied according to the anatomic site. For interactive imaging, T1-weighted GRE and T2-weighted FSE sequences were used. We performed MRI-guided transsphenoidal biopsies in 10 patients who had lesions identified by CT (n = 5) and/or MRI (n = 10). The indications for biopsies were to differentiate between suspected malignant processes (n = 4 ) and benign processes (n = 6). Lesions adjacent to structures like the internal carotid artery were accurately targeted in particular. All biopsies were performed successfully and were the basis for selection of further treatment. No complications occurred during the procedures. An open MR system allows interactive control of biopsies in the area of the petroclival region, providing maximum patient safety and diagnostic accuracy not possible in other systems. The advantages of MRI tissue characterization are combined with an interactive, one-step method of localization and targeting, as well as tissue sampling. J. Magn. Reson. Imaging 2001;13:3-11.

Biopsy, Needle↗
PubMed2001

[Value of magnetic resonance tomography for interventions in the ENT specialty].

PURPOSE: Presentation of new concepts and applications of MR-guided head and neck surgery are presented. Examples of diagnostic and therapeutic procedures such as evaluation of transseptal tumor biopsies, placement of afterloading catheters for brachytherapy, and microscopic surgery of paranasal sinuses in the open MRI are discussed. MATERIAL AND METHODS: 24 MRI-guided ENT-procedures (14 transsphenoidal biopsies, one transnasal biopsy, 6 placements of brachytherapy catheters, and 3 operations of the paranasal sinuses) were performed in an open 0.5 T MR system. RESULTS: Localisation and/or extension of all lesions as well as the placement of biopsy needles or catheters were determined with great precision during the interventions. CONCLUSIONS: Surgical risk and postoperative morbidity are significantly reduced in MR-guided surgery of the petroclival region and the region of head and neck compared to other, conventional methods. Thus, interventional MRI-guidance optimizes minimal invasive surgery and catheter placement in difficult anatomical regions like the petroclival region.

Adolescent↗