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Objectives Several plaque and lesion characteristics have been associated with an increased risk for procedural stroke during or shortly after carotid artery stenting (CAS). While technical advancements in stent design and cerebral protection devices (CPD) may help reduce the procedural stroke risk, and anatomy remains important, tailoring stenting procedures according to plaque and lesion characteristics might be a useful strategy in reducing stroke associated with CAS. In this descriptive report of the ongoing Asymptomatic Carotid Surgery Trial-2 (ACST-2), it was assessed whether choice for stent and use or type of CPD was influenced by plaque and lesion characteristics. Materials and methods Trial patients who underwent CAS between 2008 and 2015 were included in this study. Chi-square statistics were used to study the effects of plaque echolucency, ipsilateral preocclusive disease (90–99%), and contralateral high-grade stenosis (>50%) or occlusion of the carotid artery on interventionalists' choice for stent and CPD. Differences in treatment preference between specialties were also analysed. Results In this study, 831 patients from 88 ACST-2 centres were included. Almost all procedures were performed by either interventional radiologists (50%) or vascular surgeons (45%). Plaque echolucency, ipsilateral preocclusive disease (90–99%), and significant contralateral stenosis (>50%) or occlusion did not affect the choice of stent or either the use of cerebral protection and type of CPD employed (i.e., filter/flow reversal). Vascular surgeons used a CPD significantly more often than interventional radiologists (98.6% vs. 76.3%; p < .001), but this choice did not appear to be dependent on patient characteristics. Conclusions In ACST-2, plaque characteristics and severity of stenosis did not primarily determine interventionalists' choice of stent or use or type of CPD, suggesting that other factors, such as vascular anatomy or personal and centre preference, may be more important. Stent and CPD use was highly heterogeneous among participating European centres.

Because of the complex anatomy, examination of the sella turcica and hypophysis needs a dedicated MR sequence protocol. Not every sellar lesion is a pituitary adenoma. Thus, this review article summarizes the most frequently encountered intra-, supra-, and parasellar tumors and lesions. Differential diagnoses comprise besides adenoma among others craniopharyngioma, meningioma, glioma, germinoma, hamartoma, aneurysm, trigeminal schwannoma, pituitary carcinoma, chordoma, metastasis, infection, and empty sella. Characteristic imaging findings are presented and correlated to micro- and macro-pathology.

Regardless of the compartment involved, imaging of spinal infections and other spinal inflammatory diseases must be performed by magnetic resonance imaging (MRI). This allows early detection of changes in disk space or vertebral bodies. Associated paraspinal and epidural masses are depicted. However, in spinal cord inflammation MRI has a very limited specificity and cannot usually differentiate between the wide array of possible causes of intramedullary lesions. This article covers a spectrum of inflammatory lesions of the spinal cord.

Spinal tumors are often categorized into extradural, intradural extramedullary, or intramedullary. Although this classification represents somewhat of an overgeneralization as a lesion may reside in two compartments, it still helps to characterize spinal tumors. In the intradural, extramedullary space, primary tumors, such as neurofibroma and meningioma, are relatively common. Secondary tumors or leptomeningeal enhancement also occur. In the intramedullary space, primary tumors are far more common than secondary tumors or metastases.

Today stroke represents a major medical and political problem in Western industrial nations. High demands need to be placed on the initial diagnostic work-up and therapeutic treatment to ensure that the patients benefit from the recent advancements achieved in diagnostic and therapeutic fields. According to the motto "time is brain" the clinical examination and imaging have to be performed within 60 min ("door to needle time") so that potential patients can be quickly treated with systemic or intra-arterial lysis. However, it should be taken into consideration that the selection of diagnostic imaging facilities depends on several factors such as infrastructure, the time remaining in the diagnostic window, and the severity of the clinical symptoms.

The cerebellopontine angle (CPA) is an anatomically complex region of the brain. In this article we describe the anatomy of the CPA cisterns, of the internal auditory canal, the topography of the cerebellum and brainstem, and the neurovascular structures of this area.

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.

About 3% of cerebral infarcts occur in children and young individuals, and pediatric stroke is even less common. Cerebral infarcts in children have different etiologies compared to adults. The common causes are described, as well as sinus venous occlusions. Cerebral veno occlusive disease is an elusive, often underdiagnosed cause of acute neurologic deterioration.

This article describes typical head injuries in infants and children. In comparison with adults there are distinct differences in the etiology of trauma and in the kind of reaction of the skull and brain. In infants and children there are three different types of trauma: birth trauma, accidental and non-accidental injury. The typical injuries in these three groups are described.

Due to a significant overlap of the two syndromes, differentiation of degenerative dementia of the Alzheimer-type from vascular dementia may be difficult even when imaging studies are available. White matter changes occur in many patients suffering from Alzheimer's disease. Little is known about the impact of white matter changes on the course and clinical presentation of Alzheimer's disease. High sensitivity of MRI in the detection of white matter alterations may account for over-diagnosing vascular dementia. The clinical significance of white matter alterations in dementia is still a matter of debate. The article reviews current concepts about the role of white matter alterations in dementia.

To study the pattern of contrast enhancement in MR and CT of oligodendrogliomas and to compare this with other imaging findings and with histopathological grading criteria.20 patients with oligodendrogliomas (12 low-grade WHO II and 8 anaplastic WHO III) were reviewed. 20 complete MR investigations, 20 non-enhanced CT studies and 16 CTs after contrast enhancement were estimated blindly without knowledge of the tumour histological grades.All anaplastic oligodendrogliomas showed tumour contrast enhancement on MR and CT images. Also in 6/12 low-grade oligodendrogliomas the contrast was enhanced on MR imaging. In 5 of these, tumour calcifications were detected by CT. The remaining 6/12 WHO grade II cases showed no significant MR contrast enhancement. Of the oligodendrogliomas grade II, CT showed contrast uptake in 3 cases and no enhancement in 6, while in 3 cases postcontrast CT was not available. A comparison of contrast enhancement with tumour grade resulted in a p-value of 0.042 for MR and of 0.011 for CT. A combined statistical test of tumour grade and calcifications detected by CT compared with MR contrast enhancement showed a significant correlation (p=0.014).These data demonstrated that a clear grading of oligodendrogliomas based on the image criterion MR contrast enhancement was not possible. We suppose that, besides tumour neovascularisation, additional factors such as calcifications may disturb the blood-brain barrier.

While the advantages of C-arm navigation in computer-assisted spine surgery are obvious, the accuracy of pedicle screw placement with virtual fluoroscopy still needs to be verified. The C-arm-based ION system (Medtronic Sofamor Danek) was used to navigate pedicle screw insertion in patients undergoing spinal surgery for various conditions. In a prospective study, a total of 160 screws were inserted in the first 30 consecutive patients since introduction of the system at our institution: 54 at the thoracic spine (highest level: TH4) and 106 at the lumbar spine. Computed tomography (CT) scans were performed postoperatively by two independent radiologists to control the accuracy of screw placement at the level of the pedicles after reconstruction of axial images according to Laine et al. The comparison of the calculated accuracy rate of pedicle screw placement using virtual fluoroscopy with reported results achieved with CT-based navigation shows similar results for virtual fluoroscopy and a remarkable increase of accuracy in comparison to reports on conventional pedicle screw placement.

The indication for spinal angiography has to be closely set as in case of inadequate handling this procedure bares the risk of paraplegia. In unclear spinal symptoms lasting over a longer period of time, spinal vascular malformation have to be considered. Spinal vascular malformations are often reversible, especially if diagnosed early. Diagnostic methods have to include spinal angiography if other non-invasive methods do not lead to results. The main point is to consider spinal vascular malformations in unclear cases.

While the importance of stability of endoprosthetic surface structures has been recognized for some time there is a lack of comparative surveys and assessment indices that would permit comparison and improvement of surfaces on cementless endoprostheses.Using separately produced, systematically mounted specimen pieces of endoprosthetic surfaces with isolated non-linked elements of varying shapes and sizes, stability parameters and stability behaviour are described. Results of tripode-structures are compared to spherical surfaces.These investigations show clearly that geometrical attributes, the orientation and the contact of surface elements to the endoprosthetic stem influence the stability considerably more than the size of these surface elements.Using tripode-elements with different orientation, size and density, a differentiated formation of cementless endoprosthetic surfaces is possible.

While the principle of enlarging the surface area has been recognized and used in different ways for some time, there is often no schematic, detailed description or fundamental research. Taking a surface structure consisting of trabecular three-dimensional connecting elements, essential parameters are shown, making it clear that the flexible dynamic reaction of the effective "anchoring space" with a suitable specified shape (construction height, alignment, network) can be reproducibly shaped and used. This has led to a hip endoprosthesis with a graduated surface structure. The construction height of the trabecular structure varies, decreasing from proximal to distal.

Contrasting the more benign causes known for meralgia paraesthetica we report a case due to a malignant tumour of the psoas muscle. We discuss the use of sensory nerve conduction study and somatosensory evoked potentials of the lateral femoral cutaneous nerve as well as needle EMG and diagnostic nerve block to detect the site of the lesion along its course. This appears of major importance, as causes located above the inguinal ligament can bear a more serious prognosis than the ones below.

We report a rare case of a 27-year-old man presenting with an acute scrotum with simultaneous occurrence of testicular tumor and contralateral torsion. Preoperative imaging demonstrated the testicular missed torsion, yet findings were equivocal with regard to the testicular tumor. On scrotal exploration the left testis was found to be ischemic due to threefold rotation. The right testis was not identifiable, being composed of numerous necrotic lesions. Frozen section suggested malignancy, hence high right orchiectomy was performed. Histologic examination of the right testis showed mixed germ cell tumor, containing all the subtypes. To our knowledge no similar case has been reported.

Altered 5 alpha-dihydrotestosterone (DHT) metabolism and stromal-epithelial cell interactions are two factors hypothesized to explain the development of benign prostatic hyperplasia (BPH). Furthermore, the development of BPH is clearly age dependent. Therefore, we studied the age-dependent alteration of 5 alpha-reductase, the enzyme that catalyzes the irreversible conversion of testosterone to DHT in epithelium and stroma of the human prostate. For this purpose kinetic parameters [Km Vmax] of 5 alpha-reductase were determined separately in epithelium and stroma of normal prostatic tissue (NPR) from 5 and BPH tissue from 20 men, and the results were correlated with the age of the donors (15-86 yr). The mean Km in epithelium [NPR, 14.3 +/- 1.8 (+/- SE); BPH, 29.5 +/- 2.7 nmol/L] was significantly (P less than 0.0001) lower than that in stroma (NPR, 78.4 +/- 8.5; BPH, 185.8 +/- 13.6 nmol/L). The mean Vmax in epithelium [NPR, 23.8 +/- 3.9 (+/- SE); BPH, 27.9 +/- 3.0 pmol/mg protein.h] was significantly (P less than 0.0001) lower than that in stroma (NPR, 68.3 +/- 4.4; BPH, 173.8 +/- 12.2 pmol/mg protein.h). The DHT-forming index (Vmax/Km) in NPR epithelium [1.6 +/- 0.2 (+/- SE)] was significantly (P less than 0.01) higher than that in NPR stroma (0.9 +/- 0.1), while in BPH the DHT-forming index was nearly identical in epithelium (1.1 +/- 0.1) and stroma (1.0 +/- 0.1). The Km values in epithelium and stroma both correlated positively (P less than 0.01) with age, but the Vmax values correlated positively with age (P less than 0.0001) only in stroma. The DHT-forming index decreased significantly with age in epithelium (P less than 0.01), but remained constant in stroma. These results indicate that there is a nonuniform age-dependent alteration of Km and Vmax in epithelium and stroma of the human prostate independent of the presence of BPH, which might have an impact on the conversion rate of testosterone to DHT with advancing age.