On the recall of vestibular sensations.

Functional neuroimaging studies on the recall or imagination of a distinctive task in the motor network or of sensations in sensory systems (visual, acoustic, nociceptive, gustatory, and olfactory) demonstrated that the respective primary cortex is often involved in the mental imagery process. Our aim was to examine this phenomenon in the vestibular system using fMRI. Sixteen healthy subjects were asked to remember the feeling of a rotatory chair procedure in contrast to an identical situation at rest. Shortly afterwards they were asked to recall the vestibular experience in a 1.5-T scanner. The resulting activations were then compared with the responses of a galvanic vestibular control experiment and a rest condition. The vestibular recall showed significant bihemispheric activations in the inferior frontal gyri, the anterior operculum, the middle cingulate, the putamen, the globus pallidus, the premotor motor cortex, and the anterior insula. We found activations in regions known to play a role in spatial referencing, motor programs, and attention in the recall of vestibular sensations. But important known relay stations for the cortical processing of vestibular information showed neither relevant activations nor deactivations.

Detection of intracranial circulatory arrest in brain death using cranial CT-angiography.

BACKGROUND AND PURPOSE: Computed tomographic-angiography (CT-A) is becoming more accepted in detecting intracranial circulatory arrest in brain death (BD). An international consensus about the use and the parameters of this technique is currently not established. We examined intracranial contrast enhancement in CT-A after clinically confirmed BD, compared the results with electroencephalography (EEG) and Transcranial Doppler Ultrasonography (TCD) findings and developed a commonly applicable CT-A protocol. METHODS: Prospective, monocentric study between April 2008 and October 2011. EEG, TCD and CT-A were performed in 63 patients aged between 18 and 88 years (mean, 55 years) who fulfilled clinical criteria of BD. Evaluation of opacification of cerebral vascular territories in CT-A was performed in arterial as well as in venous scanning series by a neuroradiologist and a neurointensivist/neurosurgeon together. RESULTS: CT-A demonstrated a 95% sensitivity in detecting intracranial circulatory arrest when analysing arterial scanning series. We never observed venous blood return in internal cerebral veins. In three cases, BD confirmation by EEG failed because of artefacts. Confirmation of BD by TCD failed in two cases because of absent temporal window. In three cases, TCD demonstrated residual blood flow. CONCLUSION: CT-A is easily accessible in almost every hospital, offers a high spatio-temporal resolution, is operator independent and inexpensive. The results of CT-A are comparable to other established brain perfusion techniques in BD. An international consensus should be established to ascertain consistent parameters similar to fixed guidelines for other ancillary procedures to determine BD in order to prevent different scanning and evaluation protocols for detecting intracranial circulatory arrest.

Trochlear palsies caused by isolated trochlear schwannomas.

PURPOSE: To describe clinical features and management of 4 patients suffering from unilateral superior oblique palsies due to MRI-documented trochlear nerve schwannomas. METHODS: Chart reviews of 4 patients seen at the departments of ophthalmogy and neurology at the University of Mainz. RESULTS: All four patients were male, aged 36 to 72 years at initial presentation. None suffered from neurofibromatosis. The history of double vision prior presentation was 9 months to 13 years, follow-up time was 9 to 156 months. Two patients didn't receive any intervention: one remained stable over the follow-up time of 9 months. In patient #2, fourth nerve palsy was diagnosed 13 years prior to confirmation of a trochlear schwannoma by high-resolution MRI. In the third patient disturbing diplopia and head tilt were sufficiently corrected by strabismus surgery (combined oblique muscle surgery). The fourth patient had received stereotactic radiotherapy of an 8 mm schwannoma. He remained unchanged in the orthoptic measurements for 3,5 years. None of these patients developed any additional symptoms or signs of further cranial nerve or central nervous system involvement. CONCLUSION: A trochlear nerve schwannoma is a possible cause of an isolated unilateral superior oblique palsy. MRI is a helpful tool for diagnosis and follow-up. Conservative management seems to be justified as patients can remain unchanged over years.

[A capillary-based perfusion phantom for the simulation of brain perfusion for MRI]. / Ein kapillarbasiertes Phantom zur Simulation der Gehirnperfusion mit der Magnet-Resonanz-Tomografie.

PURPOSE: The measurement of the CBF is a non-standardized procedure and there are no reliable gold standards. This abstract shows a capillary-based perfusion-phantom for CE-DSC-MRI. It has equivalent flow properties to those within the tissue capillary system of the human brain and allows the validation of the Siemens Perfusion (MR) software. MATERIALS AND METHODS: The perfusion phantom consists of a dialyzer for the simulation of the capillary system, a feeding tube for simulation of the AIF and a pulsatile pump for simulation of the heart. Using this perfusion phantom, the exact determination of the gold standard CBF due to the well-known geometry of the phantom is easy. It was validated based on different perfusion measurements. These measurements were investigated with standard software (Siemens Perfusion MR). The software determined the CBF within the capillary system. Based on this CBF, a comparison to the gold standard was made with several different flow speeds. After AIF selection, a total of 726 CBF data points were automatically extracted by the software. RESULTS: This results in a comparison of the gold standard CBF to these 726 CBF values. Therefore, a reproducible and reliable deviation estimation between gold standard CBF and measured CBF using the software was computed. It can be shown that the deviation between gold standard and software-based evaluation ranges between 1 and 31 %. CONCLUSION: There is no significance for any correlation between flow speed and amount of deviation. The mean measured CBF is 11.4 % higher than the gold standard CBF (p-value < 0.001). Using this kind of perfusion-phantom, the validation of different software systems allows reliable conclusions about their quality.

Scheie syndrome: enzyme replacement therapy does not prevent progression of cervical myelopathy due to spinal cord compression.

Hurler-Scheie syndrome is caused by alpha-l-iduronidase deficiency. Enzyme replacement therapy (ERT) can improve physical capacity and reduces organomegaly. However, the effect on bradytrophic connective tissue is limited. As intravenously administered enzyme cannot cross the blood-brain barrier, the therapy of choice for the more severe Hurler syndrome is haematopoietic stem cell transplantation (HCT). In the more attenuated Scheie syndrome, neurological impairment is less severe; therefore, ERT may be appropriate to treat these patients. Information on long-term outcome in Scheie patients undergoing ERT is scarce. We report a 38-year-old female Scheie patient who has been on ERT for 8 years. While non-neurological symptoms improved, she developed paresthesias in her hands and feet and progressive pain in her legs. Somatosensory evoked potentials were abnormal, suggesting dysfunction of the dorsal funiculus and lemniscus medialis. After 6 years of ERT, a spinal MRI showed dural thickening at the upper cervical spine. These soft-tissue deposits are presumably due to the accumulation of mucopolysaccharides. Intramedullary hyperintensities at the level of C1/2 revealed cervical myelopathy. An MRI before the start of ERT had shown milder spinal lesions. Cystic lesions in the white matter of the centrum semiovale due to dilated Virchow-Robin spaces were essentially unchanged compared with the MRI scan before ERT. Decompression of the spinal cord resulted in clinical improvement. In an adult patient with Scheie syndrome, ERT failed to prevent progression of cervical myelopathy. Clinical significance of cerebral changes is unclear. Whether early HCT or intrathecal ERT could have prevented these lesions remains speculative.

[Therapy of head trauma]. / Therapie des schweren Schädel-Hirn-Traumas.

The main target of treatment in patients with head trauma is to maintain the physiological parameters within the following normal limits: intracranial pressure (ICP) below 20 mmHg, cerebral perfusion pressure (CPP) between 50 and 70 mmHg, normoxemia (SpO(2) >90%), normocapnia (paCO(2): 35-38 mmHg), normoglycemia (80-130 mg/dl) and normothermia (36.0-37.5 degrees C). Space-occupying intracranial bleeding or edemas must be evacuated immediately. If these interventions do not result in adequate control of ICP and CPP, the next step would be to administer mannitol and barbiturates. Mild hyperventilation, therapeutic hypothermia, or decompressive craniectomy should be used solely in patients with a persistent ICP increase. Infusion of calcium antagonists or glucocorticoids is never indicated in patients with head trauma.

[Pitfalls in magnetic resonance imaging. What should the anaesthesiologist know?]. / Fallgruben in der Magnetresonanztomographie. Was sollte der Anästhesist wissen?

The constantly extending indication spectrum of magnetic resonance imaging (MRI) is a challenge for the anaesthesiologist, who is being increasingly more consulted for assistance during the examination. Due to the special technology of MRI the anaesthetic technique differs substantially from that in the operating theatre. In addition to the permanent strong magnetic field the intermittently used high frequency impulses are also a potential danger for the patient. Patients with metal implants (e.g. cardiac pacemaker) are particularly at risk. For the safe treatment of patients during MRI a special MRI compatible anaesthesia equipment is necessary. Unsuitable devices can lead to malfunctioning or to projectile effects (attracting ferromagnetic objects into the magnet) causing injury to the patients. This paper describes the MRI technology and the associated dangers for the patient as well as the characteristics of the anaesthetic techniques.

[Isolated cortical vein thrombosis. Clinical and neuroradiological aspects]. / Die isolierte oberflächliche Hirnvenenthrombose. Klinisches und neuroradiologisches Spektrum.

Isolated cortical vein thrombosis is only rarely diagnosed, although it presents with typical signs on imaging, presented in the paper. We report on five patients with this diagnosis, who all presented with focal sensomotoric seizures. Imaging with CT and MRI was the leading method. All patients were treated with oral anticoagulation and showed full recovery.

Multiplex neuritis in a patient with autoimmune hepatitis: a case report.

A 37-year old woman presented with a 9-year history of hepatitis of unknown origin and aminotransferases within a 3-fold upper limit of normal. Autoimmune hepatitis (AIH) was diagnosed on the basis of elevated aminotransferases, soluble liver antigen/liver pancreas (SLA/LP) autoantibodies and characteristic histology. Immunosuppressive therapy led to rapid normalization of aminotransferases. Two years later, the patient developed left sided hemisensory deficits under maintenance therapy of prednisolone and azathioprine (AZT). Later she developed right foot drop and paraesthesia in the ulnar innervation territory on both sides. Magnetic resonance imaging (MRI) and cerebral panangiography suggested cerebral vasculitis. Neurological investigation and electromyography disclosed multiplex neuritis (MN) probably due to vasculitis. Consistent with this diagnosis, autoantibodies to extractable nuclear antigens were detectable in serum. Immunosuppression was changed to oral 150 mg cyclophosphamide (CPM0) per day. Prednisolone was increased to 40 mg/d and then gradually tapered to 5 mg. Oral CPM was administered up to a total dose of 40 g and then substituted by 6 times of an intervall infusion therapy of CPM (600 mg/m(2)). Almost complete motoric remission was achieved after 3 mo of CPM. Sensibility remained reduced in the right peroneal innervation territory. Follow-up of cranial MRI provided stable findings without any new or progressive lesions. This is the first report of multiplex neuritis in a patient with autoimmune hepatitis.

[Neuroradiology of the intracranial visual pathway. Part II]. / Neuroradiologie der intrakraniellen Sehbahn. Teil II.

Part 2 mainly presents intrinsic lesions as the most common brain tumors (astrocytoma of all grades, ependymoma), arising in the region of the visual pathway. A second focus is on vascular pathology, not only infarction, but cavernoma and venous malformation in Sturge-Weber syndrome. The third topic deals with inflammatory processes such as multiple sclerosis or sarcoidosis.

[Neuroradiological examination of the intracranial visual pathway. Part I]. / Neuroradiologie der intrakraniellen Sehbahn. Teil I.

The clinical symptoms of lesions affecting the intracranial visual pathway vary as widely as their aetiology. The anatomy, the basics of neuro-ophthalmology and MRI protocols are touched on in the first part of this serial paper; in addition the most important pathological entities affecting the sellar region are presented. The focus is on the differentiation between extrinsic and intrinsic lesions, but in addition to this vascular lesions are presented with reference to illustrative cases.

Clinical and neuroradiological spectrum of isolated cortical vein thrombosis.

BACKGROUND: Isolated cortical vein thrombosis is only rarely diagnosed, although it may commonly be overlooked. RESULTS: We report on four patients with this diagnosis who all presented with focal sensorimotor seizures. The diagnosis was made by a typical CT and MRI-pattern, which is described in detail. CONCLUSIONS: The prognosis was excellent in all patients and the treatment options are discussed.

[Neurolisteriosis with acute myelitis]. / Akute Myelitis bei Neurolisteriose.

Listeriosis is a bacterial infection with Listeria monocytogenes mostly affecting immunocompromised patients. In every fourth case, the CNS is involved, usually as meningoencephalitis. This case report of an immunocompetent woman represents the first one of neurolisteriosis initially presenting as cervical myelitis and progressing to supratentorial areas of the brain. Diagnosis was based on universal polymerase chain reaction from a cortical brain biopsy, followed by sequencing of the amplified rDNA gene. Under antibiotic treatment with gentamycin and ampicillin, the patient slowly recovered and has been improving ever since.

Reflexions about imaging technique and examination protocol 1. Computed tomography.

Computed tomography as imaging technique is established since decades, especially in examinations of the orbit. New technical development of multi-slice helical CT requires new attention, concerning radiation burden. Always asked is the use of contrast material in orbital examination. Indications and contraindications are discussed.

Anatomy of the visual system.

This brief systemic overview presents the anatomic details of the orbit with respect to imaging modalities CT and MR. The structures of the four orbital compartments, intrakonal and extrakonal space, globe and optic nerve are demonstrated in detail on different CT and MR views (axial, coronal, in soft tissue and bone window, T1-weighted, T2-weighted) with corresponding diagrams. The intracranial visual pathway is explained in detail with emphasis to the striate cortex and extrastriate visual association cortex, presented with diagrams and high-resolution MR.

Orbital pathology.

This overview of orbital pathology deals with different kinds of tumors, inflammatory, vascular, and traumatic diseases, which may involve the orbit. Depending on the respective orbital compartment of the globe, the intrakonal, extrakonal and optic nerve the most important and most frequent lesions are presented with their specific clinical symptoms. Their specific presentation on CT- and MR-imaging is discussed in detail, including the most important differential diagnosis.

Intracranial pathology of the visual pathway.

Intracranial pathologies involving the visual pathway are manifold. Aligning to anatomy, the most frequent and/or most important extrinsic and intrinsic intracranial lesions are presented. Clinical symptoms and imaging characteristics of lesions of the sellar region are demonstrated in different imaging modalities. The extrinsic lesions mainly consist of pituitary adenomas, meningeomas, craniopharyngeomas and chordomas. In (asymptomatic and symptomatic) aneurysms, different neurological symptoms depend on the location of aneurysms of the circle of Willis. Intrinsic tumors as astrocytoma of any grade, ependymoma and primary CNS-lymphoma require the main pathology in the course of the visual pathway. Vascular and demyelinating diseases complete this overview of intracranial lesions.

[Subarachnoid hemorrhage without aneurysm]. / Die Subarachnoidalblutung ohne Aneurysmanachweis.

The rupture and bleeding of intracranial aneurysms is the most common cause of a spontaneous, non-traumatic subarachnoid hemorrhage (SAH). In up to 20% of these patients, no aneurysm is found, but the prognosis of these patients is known to be better than in those with aneurysms. The retrospective evaluation of the initial CT- and angiographic findings of 773 patients with spontaneous SAH, who underwent (up to three) 4-vessel DSA, brought a percentage of 12.4% with negative angiography. We found the favourable prognosis of these patients with negative angiography not only to be dependent from the distribution of the hemorrhage, with preference to perimesencephalic pattern, but the initial clinical state. 85% of our patients, who presented with perimesencephalic blood pattern and even 80% of those patients with additional intraventricular hemorrhage but the good clinical condition of Hunt-Hess I/II were discharged without neurological deficits. We recommend the obligatory 4-vessel catheter-angiography (DSA) in all patients with spontaneous SAH, independent of the blood pattern on initial CT, and one control in the presence of other than perimesencephalic subarachnoid hemorrhage, CTA might be reserved for additional controls.