[Anatomy and malformations of the posterior cranial fossa]. / Anatomie und Fehlbildungen der hinteren Schädelgrube.

Many important structures are located in the confined space within the posterior cranial fossa. This article describes the main aspects of the anatomy. As a uniform classification of malformations of the posterior cranial fossa does not exist the main syndromes, such as Chiari malformations, zerebellar hypoplasia and dysplasia are discussed separately.

[Radiation dose in cerebral angiography and flat detector CT applications in neuroradiology]. / Strahlendosis bei zerebraler Angiographie und Flachdetektor-CT-Applikationen in der Neuroradiologie.

Flat detectors (FD) have completely replaced image intensifiers in angiography. Due to this development not only the image quality of 2D digital subtraction angiography series (2-D-DSA) could be improved but also the acquisition of computed tomography (CT)-like cross-sectional images (FD-CT) within the angio suite became feasible. These techniques are now being used in daily clinical routine. Only little information about effective doses of these applications to patients has been published in the literature. We describe the effective patient dose of current applications in the field of angiography and demonstrate strategies to minimize the dose to the patient. In addition, we compare FD-CT applications to standard multislice CT applications.

Visualization and monitoring of acute epistaxis during endovascular treatment using a flat detector CT.

BACKGROUND: Epistaxis is one of the most common emergencies of ENT surgery and can be managed conservatively in most cases. However, transarterial embolization is an accepted treatment option for intractable epistaxis, if conservative management fails. But often, direct detection of the bleeding point by obvious contrast extravasation is not possible in conventional subtracted angiographic series (DSA). Then the suspected bleeding point is treated by endovascular embolization based on the clinical suspicion. CASE REPORT: We here present the case of a young woman with intractable epistaxis where hemorrhage with contrast extravasation was only faintly visible. We used the new imaging modality of flat detector computed tomography (FD-CT) to visualize acute hemorrhage and treatment effect accurately. CONCLUSION: FD-CT was helpful to visualize both irregular branches of the bleeding mucosa and active hemorrhage and also to monitor an effective embolization within the angio suite. Acquisition of FD-CT imaging in addition to conventional 2-D imaging with the same system enhances the possibility to a better understanding of the individual patient's anatomy and could be beneficial in the accurate depiction of active bleeding, and it might also improve surgical management, if endovascular attempts should fail.

Endovascular treatment of symptomatic radiation-induced basilar artery stenosis 25 years after medulloblastoma.

Intracranial stenosis as late sequela after cerebral radiation therapy for medulloblastoma is an exceptionally rare finding. We report for the first time a case of 31-year-old patient with a history of medulloblastoma 25 years ago and now presenting with radiation-induced high-grade basilar stenosis and recurrent ischemic symptoms despite best medical therapy. The stenosis was treated successfully with angioplasty followed by stenting using a self-expandable microstent. Additionally, MRI revealed multiple cavernomas, illustrating that radiation-induced microbleeds may occur.

[Myosin storage myopathy: a rare subtype of protein aggregate myopathies]. / Myosinspeichermyopathie: eine seltene Unterform der Proteinaggregationsmyopathien.

Myopathies with pathological protein aggregates comprise a numerically significant group of sporadic and hereditary muscle disorders. A rare disease entity within the group of protein aggregate myopathies is the myosin storage myopathy, which is caused by heterozygous mutations in the MYH7 gene which encodes the slow/beta-myosin heavy chain. We report the clinical, myopathological and MRI findings in the first German patient suffering from a myosin storage myopathy due to a heterozygous R 1845W missense mutation.

In vivo imaging of MSCT and micro-CT: a comparison.

PURPOSE: To evaluate the potential of MSCT and a novel AmicroCT system to assess the volume of malignant brain tumors in rats compared to histology. MATERIALS AND METHODS: Fourteen rats underwent stereotactic implantation of GFP-marked F 98-glioma cells. On day 10 after implantation, animals received double-dose contrast-enhanced AmicroCT and MSCT imaging using Iomeprol. MSCT- and AmicroCT-derived tumor volumes were calculated and compared to histology (fluorescence staining) as the gold standard. RESULTS: There was good correlation between the AmicroCT-derived tumor volume (69 A+ or - 23 mm(3)) and histology (81 A + or - 14 mm(3); p > 0.14). MSCT, however, showed significantly smaller tumor volumes (55 A + or - 25 mm(3)) compared to histology (p < 0.01) but was able to detect the tumors in all animals. CONCLUSION: AmicroCT allows in vivo imaging of the contrast-enhancing parts of experimental gliomas with high correlation to histology. Although MSCT is less suitable for assessing exact tumor volume, this method reliably detects tumors in rats. Due to the high spatial resolution, AmicroCT-systems could play an important role for fusion imaging, e. g. to assess experimental brain gliomas with multimodal AmicroCT/PET- or AmicroCT/MRI-fusion images.

[Flat-detector computed tomography in diagnostic and interventional neuroradiology]. / Flachdetektor-CT in der diagnostischen und interventionellen Neuroradiologie.

Originally aimed at improving standard radiography by providing higher absorption efficiency and a wider dynamic range than available with film-screen and phosphor luminescence, radiography flat detector technology is now widely accepted for neuroangiographic imaging. Especially flat-detector computed tomography (FD-CT), which uses rotational C-arm mounted flat-panel detector technology, is capable of volumetric imaging with a high spatial resolution. As "angiographic CT" FD-CT may be helpful in many diagnostic and neurointerventional procedures, e.g. intracranial stenting for cerebrovascular stenoses, stent-assisted coil embolization of wide-necked cerebral aneurysms and embolization of arteriovenous malformations. By providing morphologic, CT-like images of the brain within the angiography suite FD-CT allows rapid visualization of periprocedural hemorrhaging and may thus improve rapid complication management without the need of patient transfer. In addition, myelography and postmyelographic FD-CT imaging can be carried out using a single modality. Spinal interventions, such as kyphoplasty or vertebroplasty might also benefit from FD-CT. Imaging of the temporal bone may also develop into an important field of FD-CT. This paper briefly reviews the technical principles of FD technology and the potential applications in diagnostic and interventional neuroradiology.

Coil migration after endovascular coil occlusion of internal carotid artery pseudoaneurysms within the sphenoid sinus.

INTRODUCTION: We report two cases of coil migration after endovascular treatment of pseudoaneurysm of the internal carotid artery within the sphenoid sinus with coils and noncovered stents. CASE REPORTS: Two patients underwent sphenoid sinus exposure for pituitary adenoma and chronic infection, respectively. As a complication pseudoaneurysms of the internal carotid artery within the sphenoid sinus developed. One patient was treated with stent and coils, the second with coils alone. Both patients experienced coil migration after 9 and 26 months, respectively, with the necessity for further treatment. Imaging was performed using flat detector computed tomography (FD-CT). Literature review revealed two additional cases of coil migration and four patients with the same treatment in stable condition. CONCLUSION: Pseudoaneurysms of the internal carotid artery are a special entity and the environment of the aneurysm within the sphenoid sinus may change over a long time. Coil embolization may lead to the late onset complication of coil migration with the possible risk of acute epistaxis. As a consequence, these patients need a careful and prolonged follow up. FD-CT is an appropriate technique to visualize the implanted coils and if present the migration of coil material.

Hyperperfusion syndrome after carotid stent angioplasty.

INTRODUCTION: This study assesses the incidence and causes of hyperperfusion syndrome occurring after carotid artery stenting (CAS). MATERIALS AND METHODS: We retrospectively reviewed the clinical database of 417 consecutive patients who were treated with CAS in our department to identify patients who developed hyperperfusion syndrome and/or intracranial hemorrhage. Magnetic resonance imaging (MRI) including fluid-attenuated inversion recovery and diffusion-weighted imaging was performed before and after CAS in 269 cases. A Spearman's rho nonparametric correlation was performed to determine whether there was a correlation between the occurrence/development of hyperperfusion syndrome and the patient's age, degree of stenosis on the stented and contralateral side, risk factors such as diabetes, smoking, hypertension, adiposity, gender and fluoroscopy time, and mean area of postprocedural lesions as well as preexisting lesions. Significance was established at p < 0.05. RESULTS: Of the 417 carotid arteries stented and where MRI was also completed, we found hyperperfusion syndrome in 2.4% (ten cases). Patients who had preexisting brain lesions (previous or acute stroke) were at a higher risk of developing hyperperfusion syndrome (p = 0.022; Spearman's rho test). We could not validate any correlation with the other patient characteristics. CONCLUSION: Extensive microvascular disease may be a predictor of hyperperfusion syndrome after carotid stent placement. We believe that further studies are warranted to predict more accurately which patients are at greater risk of developing this often fatal complication.

Flat panel detector angiographic CT in the management of aneurysmal rupture during coil embolization.

Angiographic CT (ACT) produces CT-like images within minutes in the angiography suite. We present the cases of 2 patients with intraprocedural aneurysmal rupture in which ACT enabled the neuroradiologist to rapidly assess the extent of bleeding during endovascular treatment. Additionally, ACT revealed pronounced rebleeding within the time between conventional CT and onset of treatment. In the management of aneurysmal rupture during coil embolization, ACT may be a valuable adjunct.

In vivo detection of hepatitis C virus (HCV) RNA in the brain in a case of encephalitis: evidence for HCV neuroinvasion.

We report here a 27-year-old woman who presented with encephalitis of unknown origin. Magnetic resonance imaging (MRI) of the brain revealed leukoencephalopathy, cerebrospinal fluid showed signs of inflammation. Serum and brain biopsy tissue was tested positive for hepatitis C virus (HCV). Neuropathological investigation supported the hypothesis of viral encephalitis. C3, C4 and cryoglobulins as well as cerebral MR-angiography were normal. Neurological complications of HCV infection other than hepatic encephalopathy are generally attributed to parainfectious phenomena. This is the first case of HCV-RNA detection in vivo in human brain in literature and it raises the possibility that HCV is able to induce encephalitis caused by neurotrophism. This is supported by the fact that there is a growing body of literature on HCV-induced cerebral dysfunction and laboratory findings indicating HCV neuroinvasion.

[Vascular anomalies of the cerebellopontine angle]. / Vaskuläre Erkrankungen des Kleinhirnbrückenwinkels.

Vascular anomalies of the cerebellopontine angle are rare compared to tumors in this area. Irritation of the trigeminal, facial, or vestibulocochlear nerve may cause trigeminal neuralgia, hemifacial spasm and vertigo, or tinnitus accordingly. Vessel loops in the cerebellopontine cisterns may cause compression at the root entry or exit zone of the cranial nerves V, VII, and VIII, a phenomenon which is called "vascular loop syndrome." Megadolichobasilar artery and aneurysms of the vertebrobasilar system can also lead to dislocation and compression of the cranial nerves and brain stem. Three-dimensional CISS MR imaging and MR angiography are useful in the detection of neurovascular compression. Microvascular decompression is an effective surgical procedure in the management of compression syndromes of the cranial nerves V, VII, and VIII.

[Imaging diagnostics of the pharynx and larynx]. / Bildgebende Diagnostik von Pharynx und Larynx.

The pharynx and larynx represent very sophisticated regions and may be involved in a diverse range of pathologic conditions. Evaluation of the head and neck has developed significantly with the establishment of CT and MRI as they provide true insights into the endoscopically blind areas as well as depth of tumor infiltration, its submucosal growth and contralateral involvement, cartilage invasion, bone marrow invasion, and nonpalpable adenopathy. Inflammations in the head and neck region are only exceptionally imaged with CT or MRI; indications are the diagnosis of retrotonsillar and parapharyngeal abscesses and ensuing complications. The different imaging modalities of malignant pharyngeal and laryngeal tumors and their differential diagnosis are presented in this paper.

[Spinal intradural tumors]. / Spinale intradurale Tumore.

Spinal intradural tumors are uncommon lesions but may cause significant morbidity. In establishing the differential diagnosis for a spinal lesion, location, age, and the patient's clinical presentation are important. Magnetic resonance imaging plays a central role in the visualization of spinal tumors, easily allowing tumors to be classified as extradural, intradural extramedullary, or intramedullary which is very useful in tumor characterization. We describe intradural tumors; the majority is extramedullary, with nerve sheath tumors being the most frequent. Intramedullary tumors are uncommon spinal tumors. Ependymomas and astrocytomas comprise the majority of this group. Typical imaging features of both intradural extramedullary and intramedullary tumors are described.

[Treatment of arteriosclerotic carotid stenosis: an overview]. / Behandlung der arteriosklerotischen Karotisstenose: ein Uberblick.

Endarterectomy for extracranial carotid stenosis has proven to be the method of choice for symptomatic patients suffering from ischemia (NASCET, ECST). The effectivity of the operation for asymptomatic stenosis seems to be likely since the publication of the first results of the ACST trial. The safety and efficiency of carotid stenting has not been proven so far and has to be evaluated in randomized trials comparing surgery and endovascular treatment. We provide an overview of the current trials and try to define the role of carotid stenting.

[Screening for aneurysms in risk groups: meaningful?]. / Aneurysmascreening in Risikogruppen: Sinnvoll?

There is a controversy discussion on screening for aneurysms in risk groups. True guidelines do not exist so far. It seems that screening for familial aneurysms is not advisable today. But adult dominant polycystic kidney disease (ADPKD) patients with a familial history of SAH should be screened because of a high prevalence rate of 25% for intracranial aneurysms in this population. Screening should be performed every 2 to 3 years by MRI angiography in this special risk group.