Biomedical subjects
Publications and source records attributed to I Grunwald.
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.
Spondylitis is an inflammation of the vertebral body. If the infection is manifested in the vertebral motor segment it is called spondylodiscitis, which can be divided into specific and nonspecific forms. It is clinically impressive that at the beginning of the disease, the patients who are quite often immunosuppressed suffer from localized, especially nocturnally exacerbated backache. The initial diagnostic work-up generally consists of clinical history, examination, laboratory tests, and (especially advanced) imaging findings. Although computed tomography still remains the most frequently used advanced imaging technique, magnetic resonance imaging is the golden standard for the diagnosis of spondylitis and spondylodiscitis.
Modern imaging techniques have great importance in the diagnosis and therapy of skull-base pathologies. Many of these lesions, especially in relation to their specific location, can be evaluated using CT and MR imaging. Tumors commonly found in the anterior skull base include carcinoma, rhabdomyosarcoma, esthesioneuroblastoma and meningioma. In the central cranial fossa, nasopharyngeal carcinoma, metastases, meningioma, pituitary adenoma and neurinoma have to be considered. The most common neoplasms of the posterior skull base, including the CP angle, are neurinoma, meningioma, nasopharyngeal carcinoma, chordoma and paraganglioma. One major task of imaging is the evaluation of the exact tumor extent as well as its relationship to the neighboring neurovascular structures. The purpose of this review is to recapitulate the most important anatomical landmarks of the skull base. The typical imaging findings of the most common tumors involving the skull base are also presented.
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.
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.
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.
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.
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.
In Germany about 400 children are diagnosed of having a brain tumour each year. About half of them are located in the supratentorial region. Despite the fact, that brain tumours are the most common solid tumour in childhood, they are very heterogeneous, regarding clinical symptoms, pathology, treatment and prognosis. Imaging studies play an important role for diagnosis and follow-up.
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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.
PURPOSE: 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. MATERIAL AND METHODS: 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. RESULTS: 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). CONCLUSION: 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.
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.
The current study examined the effects of age and gender on emotional and nonemotional expression using an experimental word list generation (WLG) task (also referred to in the literature as verbal fluency) from the New York Emotion Battery (Borod, Welkowitz, & Obler, 1992). Subjects were 28 young ( M = 29.6 years), 28 middle-aged (M = 49.8 years), and 28 older (M = 69.9 years) healthy adults. The WLG task consists of 8 emotional (E; 3 positive and 5 negative) and 8 nonemotional (NE) categories. We developed and present here a detailed word error-type analysis that was used to evaluate the lexical output. In this study, both quantitative (amount of output and error-types) and qualitative (accuracy and intensity) analyses were used. While subjects produced more nonemotional than emotional words and more positive than negative words, the amount of error-free output and the number of errors did not change with age. An age group by error-type interaction indicated that older adults, especially men, produced more repetition errors than younger adults. The error-free output was subsequently rated for accuracy and emotional intensity. The rating data revealed that older women's overall lexical output was less accurate than that produced by younger women. Also, negative emotional words were more accurate and intense than positive emotional words. The procedures described here have implications for research assessing word list generation and emotional expression in clinical populations.
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.
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 compared the effects of fixed and variable (proportional) spacing on reading speeds and found variable pitch to yield better performance at medium and large character sizes and fixed pitch to be superior for character sizes approaching the acuity limit. The data indicate at least two crowding effects at the smallest sizes: one that interferes with individual character identification and one that interferes with word identification. A control experiment using rapid serial visual presentation suggests that it is the greater horizontal compression and consequently reduced eye-movement requirements of variable pitch that are responsible for its superiority at medium and large character sizes.