[Complication after Embolization of an AVM with Onyx].

Report on a 34-year-old woman with an arteriovenous malformation (AVM) in the area of the right hippocampus. On the basis of an interdisciplinary indication for step-by-step embolization of the AVM, the first partial embolization with Onyx occurred successfully and without complications. 10 days later, the second partial embolization also turned out well, but during retraction of the microcatheter an exit of Onyx happened into the guiding catheter in spite of continuous aspiration.

Short TE single-voxel 1H-MR spectroscopy of hippocampal structures in healthy adults at 1.5 Tesla--how reproducible are the results?

The purpose of our study was to evaluate inter- and intra-subject variability and scan-rescan reproducibility of single-voxel 1H-MR spectroscopy (1H-MRS) in hippocampal structures at 1.5 T field strength. Thirty healthy adults were studied bilaterally by optimized, standardized short echo time single-voxel 1H-MRS (PRESS, TE=30 ms, TR=3000 ms, oblique voxel orientation, voxel size 2 cm3).

Internal carotid artery injury during functional endoscopic sinus surgery and its management.

Rupture of the internal carotid artery (ICA) during functional endoscopic sinus surgery (FESS) is a rare complication, which can potentially result in death. Only a few cases have been reported in the literature thus far. We present four cases with an ICA bleeding during sphenoidotomy.

[Multimodal computed tomography in acute cerebral infarction. Experience with a standardized protocol in 100 patients].

Computed tomography (CT) is the standard method of brain imaging in acute stroke. To an experienced examiner, nonenhanced CT will exclude hemorrhage and may indicate early ischemic signs. Reliable description of an ischemic area and the underlying vascular disease is not possible in the acute phase but is possible, particularly within the first hours, when therapeutic decisions on matters such as systemic thrombolysis are to be made.

Three-dimensional visualization of neurovascular relationships in the posterior fossa: technique and clinical application.

Object: The goal of this study was to describe the authors' technique for three-dimensional (3D) visualization of neurovascular relationships in the posterior fossa at the surface of the brainstem. This technique is based on the processing of high-resolution magnetic resonance (MR) imaging data. The principles and technical details involved in the accurate simultaneous visualization of vessels and cranial nerves as tiny structures are presented using explicit and implicit segmentation as well as volume rendering.

CT angiography of intracranial aneurysms: a focus on postprocessing.

Computed tomographic (CT) angiography is a well-known tool for detection of intracranial aneurysms and the planning of therapeutic intervention. Despite a wealth of existing studies and an increase in image quality due to use of multisection CT and increasingly sophisticated postprocessing tools such as direct volume rendering, CT angiography has still not replaced digital subtraction angiography as the standard of reference for detection of intracranial aneurysms. One reason may be that CT angiography is still not a uniformly standardized method, particularly with regard to image postprocessing.

[Thrombus attached to a Sideris septal occluder system 6 years later].

History And Clinical Findings: A 61-year-old man was admitted to hospital because of right-sided hypaesthesia. Additionally he reported a brief speech disturbance some weeks before. Neurological examination indicated right-sided sensomotoric hemiparesis and left-sided upper quadrant anopia.

[Time consumption and quality of an automated fusion tool for SPECT and MRI images of the brain].

Aim: Although the fusion of images from different modalities may improve diagnostic accuracy, it is rarely used in clinical routine work due to logistic problems. Therefore we evaluated performance and time needed for fusing MRI and SPECT images using a semiautomated dedicated software. PATIENTS, MATERIAL AND METHOD: In 32 patients regional cerebral blood flow was measured using (99m)Tc ethylcystein dimer (ECD) and the three-headed SPECT camera MultiSPECT 3.

1H-MR spectroscopy: a promising method in distinguishing subgroups in temporal lobe epilepsy?

Proton MR spectroscopy offers an additional noninvasive method of supporting focus lateralization in patients with intractable temporal lobe epilepsy. In this study involving 57 patients, the ability of multivoxel 1H-MRS to differentiate between mesial and lateral TLE was investigated in addition to its ability to lateralize the epileptogenic focus. Temporal lobe epilepsy (TLE) was classified into mesiobasal or lateral temporal lobe epilepsy according to the results of preoperative diagnostics including neurological and neuropsychological examinations, video-EEG monitoring and high resolution MRI.

Standardized evaluation of CT angiography with remote generation of 3D video sequences for the detection of intracranial aneurysms.

Computed tomography (CT) angiography is a well-known imaging technique commonly applied to both the detection and therapy planning of intracranial aneurysms. For this purpose, current studies predominantly focus on three-dimensional (3D) representations of CT angiographic volumes obtained with varying visualization approaches on different computers. Interactive manipulation performed by users individually is an important prerequisite for data analysis.

Comprehensive imaging of ischemic stroke with multisection CT.

Computed tomography (CT) is an established tool for the diagnosis of ischemic or hemorrhagic stroke. Nonenhanced CT can help exclude hemorrhage and detect "early signs" of infarction but cannot reliably demonstrate irreversibly damaged brain tissue in the hyperacute stage of ischemic stroke. Further evaluation of patients with ischemic stroke should include differentiation between reversible and irreversible brain damage, which is essential for choosing an appropriate therapy.

Somatosensory evoked magnetic fields following passive movement compared with tactile stimulation of the index finger.

Cortical processing of passive finger movement was assessed magnetoencephalographically in 12 healthy volunteers and compared with somatosensory evoked magnetic fields (SEF) following tactile stimulation. A new device comprising a clamp-like digit holder facilitated bilateral guidance of the briskly elevated index finger. Both passive movement and tactile stimulation induced activation of the contralateral primary somatosensory (SI) cortex, indicated by six SEF deflections with inter-individually rather consistent peak latencies of 20-230 ms following proprioceptive and 20-300 ms following tactile stimulation.

Post-apoplectic reorganization of cortical areas processing passive movement and tactile stimulation--a neuromagnetic case study.

Magnetoencephalography (MEG) was used in a patient with right centro-parietal stroke to investigate the cortical processing of tactile pneumatic stimulation and passive movement of the impaired left and unaffected right-hand index finger. Source localization of somatosensory evoked magnetic fields (SEF) recorded 2 weeks after infarction demonstrated a spatial displacement of the contralateral SI generators in the affected hemisphere. The distance between SI sources activated by either stimulation technique was noticeably enlarged in comparison to the left hemisphere and to previous data from 12 healthy subjects.

Cyst-like cerebral lesions in tuberous sclerosis.

Known brain manifestations of tuberous sclerosis (TSC) are cortical sclerotic tubera, giant cell astrocytomas, subependymal calcified nodules in the lateral walls of the lateral ventricles, and white matter heterotopias. In addition, small cyst-like lesions in the white matter have been described. We report on three TSC patients with hitherto undescribed large cyst-like cerebral lesions in subcortical and white matter locations.

Factors influencing the application accuracy of neuronavigation systems.

Objective: The overall accuracy of neuronavigation systems may be influenced by (1) the technical accuracy, (2) the registration process, (3) voxel size and/or distortion of image data and (4) intraoperative events. The aim of this study was to test the influence of the registration and imaging modality on the accuracy.

Methods: A plexiglas phantom with 32 rods was taken for navigation targeting.

Somatotopic organization of the ventral and dorsal finger surface representations in human primary sensory cortex evaluated by magnetoencephalography.

Cortical reorganization of the subtly differentiated hand map after peripheral nerve injury might be better understood if there was a topographic conception of the homuncular representation of the dorsal finger surfaces in humans, in addition to the well-established sequential rostrocaudal array of the ventral finger aspects in cortical area 3b. In the present magnetoencephalographic study, tactile pneumatic stimulation was delivered to the fingertip and to the ventral and dorsal proximal phalanx of each digit of the dominant hand in 20 right-handed volunteers. Source localization of equivalent current dipoles underlying the recorded somatosensory evoked magnetic field was performed using a Cartesian coordinate system established by the anatomical landmarks nasion and preauricular points.

Severe neurological complications of ulcerative colitis.

A 37 year old man presented with a 15 year history of ulcerative colitis. On examination he had weakness of the right arm, slurred speech and progressive confusion, followed by a rapid deterioration of consciousness and motor functions resulting in coma, tetraparesis and bilateral Babinski responses. Magnetic resonance imaging of the brain and spinal cord revealed multiple hyper- and hypointense white matter lesions.

Local and remote visualization techniques for interactive direct volume rendering in neuroradiology.

The increasing capabilities of magnetic resonance (MR) imaging and multisection spiral computed tomography (CT) to acquire volumetric data with near-isotropic voxels make three-dimensional (3D) postprocessing a necessity, especially in studies of complex structures like intracranial vessels. Since most modern CT and MR imagers provide limited postprocessing capabilities, 3D visualization with interactive direct volume rendering requires expensive graphics workstations that are not available at many institutions. An approach has been developed that combines fast visualization on a low-cost PC system with high-quality visualization on a high-end graphics workstation that is directly accessed and remotely controlled from the PC environment via the Internet by using a Java client.

[Rapid interactive 3-D imaging of the temporal bone with "direct volume rendering"].

Introduction: For the first time, the relatively new method of interactive direct volume rendering (dVR) allows for a fast and direct three-dimensional visualization of spiral CT data without any manual, explicit segmentation. This study was performed to prove whether dVR is capable of providing a meaningful three-dimensional visualization of the structures within the temporal bone.

Patients And Methods: In ten patients a three-dimensional visualization of the structures of the inner and middle ear was performed from spiral CT data on a commercially available graphics workstation.

[Diagnostic imaging in refractory temporal lobe epilepsy. A comparison of MR volumetry and multivoxel-MR-spectroscopy for assessment of postoperative prognosis].

While the importance of magnetic resonance (MR) spectroscopy, volumetry, and T2-relaxometry for preoperative localization has already been verified, the question arises as to what extent the individual techniques are useful for assessing postoperative prognosis with respect to seizures and neuropsychological outcome. In a prospective comparative study, 26 patients were examined preoperatively with a 1.5 T whole-body scanner.

Alteration of the somatosensory cortical map in peripheral mononeuropathy due to carpal tunnel syndrome.

Substantial plasticity of the mature mammalian somatosensory cortex was demonstrated after deprivation of sensory input produced by amputation or somatosensory deafferentation. Following transection of the median nerve, adult owl and squirrel monkeys exhibit extensive reorganization in the cortical representation of the hand in areas 3b and 1. In the present study we investigated the possible effect of incomplete median nerve damage on sensory cortex somatotopy in a patient with unilateral carpal tunnel syndrome.

The significance of bilateral CSI changes for the postoperative outcome in temporal lobe epilepsy.

Purpose: In a prospective study, we evaluated the significance of preoperative bilateral chemical shift spectroscopy imaging (CSI) changes for the prognosis of postoperative seizure outcome in the surgical treatment of patients with temporal lobe epilepsy (TLE).

Method: CSI using multivoxel spectroscopy was performed. Twenty-six consecutive TLE patients scheduled for epilepsy surgery were included.