Sympathetic activation triggers systemic interleukin-10 release in immunodepression induced by brain injury.

The mechanism of immunodepression after brain injury is not yet clear. Here we demonstrate rapid systemic release of the immunoinhibitory cytokine interleukin-10, monocytic deactivation and a high incidence of infection in patients with 'sympathetic storm' due to acute accidental or iatrogenic brain trauma. In vitro studies showed that within minutes catecholamines trigger the secretion of interleukin-10 from unstimulated monocytes through a beta-adrenoreceptor-mediated, cAMP/protein kinase A-dependent pathway. We found that in a rat model of acute brain injury, the beta-receptor antagonist propranolol prevented the increase of interleukin-10 plasma levels. Rapid monocytic interleukin-10 release after sympathetic activation may represent a common pathway for immunodepression induced by stress and injury.

Mechanisms of brain-mediated systemic anti-inflammatory syndrome causing immunodepression.

Overwhelming inflammatory immune response can result in systemic inflammation and septic shock. To prevent excessive and deleterious action of proinflammatory cytokines after they have produced their initial beneficial effects, the immune system can release several anti-inflammatory mediators, including interleukin-10, interleukin-1 receptor antagonist, and soluble tumor necrosis factor receptors, thus initiating a compensatory anti-inflammatory response syndrome. However, in vivo the delicate balance between pro- and anti-inflammatory responses is additionally controlled by the central nervous system. Therefore, proinflammatory cytokines stimulate the hypothalamic-pituitary-adrenal axis and enhance sympathetic nerve system activity. The mediators of these neuroimmune pathways can again suppress immune cell functions to control systemic inflammation. The question is, however, what happens if the immunoinhibitory CNS pathways are activated without systemic inflammation? This can result from production of cytokines in the brain following infection, injury, or ischemia or in response to various stressors (e.g., life events, depression, anxiety) or directly from brainstem irritation. The answer is that this may generate a brain-mediated immunodepression. Many animal and clinical studies have demonstrated a stress and brain cytokine mediated decrease in the cellular immune response at the lymphocyte level. More recently, the importance of monocytes in systemic immunocapacity has been shown. Monocytic inactivation with decreased capability of antigen presentation and depressed secretion of proinflammatory cytokines increases the risk of infectious complications. Interestingly, cytokines in the brain and other stressors can also generate systemic immunodepression at the monocyte level. In this scenario the catecholamine-induced release of the potent anti-inflammatory cytokine interleukin-10 is a newly discovered mechanism of the brain-mediated monocyte deactivation in addition to the "well known" immunosuppressive action of glucocorticoids. Furthermore, other neuropeptides such as alpha-melanocyte-stimulating hormone and beta-endorphin which can be released in stressful situations have also inhibitory effects on immune cells. Thus mediators of the CNS are implicated in the regulation of immune functions and may play a role in both conditioning the host's response to endogenous or exogenous stimuli and generating a "brain-mediated" immunodepression.

Relation of cerebral energy metabolism and extracellular nitrite and nitrate concentrations in patients after aneurysmal subarachnoid hemorrhage.

In a prospective clinical investigation on neurochemical intensive care monitoring, the authors' aim was to elucidate the temporal profile of nitric oxide metabolite concentrations-that is, nitrite and nitrate (NO(x))--and compounds related to energy-metabolism in the cerebral interstitium of patients after aneurysmal subarachnoid hemorrhage (SAH). During aneurysm surgery, microdialysis probes were implanted in cerebral white matter of the vascular territory most likely affected by vasospasm. Temporal profiles of NO(x) were analyzed in a subset of 10 patients (7 female, 3 male, mean age = 47 +/- 14 years). Microdialysis was performed for 152 +/- 63 hours. Extracellular metabolites (glucose, lactate, pyruvate, glutamate) were recovered from the extracellular fluid of the cerebral parenchyma. NO(x) was measured using a fluorometric assay. After early surgery, SAH patients revealed characteristic decreases of NO(x) from initial values of 46.2 +/- 34.8 micromol/L to 23.5 +/- 9.0 micromol/L on day 7 after SAH (P < 0.05). Decreases in NO(x) were seen regardless of development of delayed ischemia (DIND). Overall NO(x) correlated intraindividually with glucose, lactate, and glutamate (r = 0.58, P < 0.05; r = 0.32, P < 0.05; r = 0.28, P < 0.05; respectively). After SAH, cerebral extracellular concentrations of NO metabolites decrease over time and are associated with concomitant alterations in energy-or damage-related compounds. This could be related to reduced NO availability, potentially leading to an imbalance of vasodilatory and vasoconstrictive factors. On the basis of the current findings, however, subsequent development of DIND cannot be explained by a lack of vasodilatory NO alone.

Brain-IL-1beta induces local inflammation but systemic anti-inflammatory response through stimulation of both hypothalamic-pituitary-adrenal axis and sympathetic nervous system.

It is well established that systemic inflammation induces a counter-regulatory anti-inflammatory response particularly resulting in deactivation of monocytes/macrophages. However, recently we demonstrated a systemic anti-inflammatory response without preceding signs of systemic inflammation in patients with brain injury/surgery and release of cytokines into the cerebrospinal fluid (CSF). In order to analyze the mechanisms and pathways of systemic immunodepression resulting from sterile cerebral inflammation we established an animal model using continuous intra-cerebroventricular (i.c.v.) or intra-hypothalamic (i.h.) infusion of rat recombinant (rr) tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta for 48 h. Controls received intra-venous (i.v.) cytokine administration. Interestingly, i.c.v. and i.h. infusion of IL-1beta but not TNF-alpha produced distinct signs of central nervous system (CNS) inflammation. Correspondingly, i.c.v. infusion of IL-1beta particularly diminished the TNF-alpha but increased the IL-10 concentration in whole blood cultures after endotoxin stimulation. All parameters normalized within 48 h after termination of the infusion. Blocking the hypothalamic-pituitary-adrenal (HPA) axis by hypophysectomy (HPX) led to complete recovery of the diminished TNF-alpha concentration and temporarily inhibited the IL-10 increase. Blocking the sympathetic nervous system (SNS) transmission by application of the beta2-adrenoreceptor antagonist propranolol not only inhibited the increase but further downregulated the endotoxin induced IL-10 concentration in the media of whole blood cell cultures, whereas the TNF-alpha decrease was only partially prevented. Interestingly, HPX and propranolol also diminished the cell invasion into the CSF. In summary, activation of both the HPA axis and the SNS plays an important role in systemic anti-inflammatory response resulting from cytokines in brain and cerebral inflammation.

Effects of barium on stimulus-induced changes in [K+]o and field potentials in dentate gyrus and area CA1 of human epileptic hippocampus.

The effects of barium on stimulus-induced rises in [K+]o were studied in the dentate gyrus (DG) and area CA1 of human hippocampal slices. Rises in [K+]o elicited by repetitive stimulation of the hilus, stratum moleculare, alveus, or stratum radiatum were dependent on stimulus intensity and frequency. Barium augmented rises in [K+]o in the DG by about 120% but failed to do so in area CA1. In both DG and area CA1 barium had no effects on population spikes whereas stimulus-induced slow field potentials were reduced. Since barium interferes with K+ uptake and redistribution by blocking leak conductances and inwardly-rectifying currents in astrocytes, our findings suggest that glial cells in the sclerotic hippocampal area CA1 may contribute less to K+ regulation.

Hyperostosis in meningiomas: MR findings in patients with recurrent meningioma of the sphenoid wings.

PURPOSE: We used MR imaging to analyze retrospectively the pattern of hyperostosis occurring concomitantly with recurrent sphenoid wing meningiomas. METHODS: Bone involvement was compared in 12 corresponding CT and MR studies of 10 female patients with sphenoid wing meningiomas recurrence after earlier surgical treatment. Four of these had histologically confirmed meningiomatous infiltration of the bone. RESULTS: All patients had CT findings of localized hyperostosis of parts of the sphenoid wings. MR revealed inhomogeneous areas of slightly increased signal intensity in hyperostotic bone on T2-, proton density- and T1-weighted sequences. In nine of 10 patients, segments of the hyperostotic bone showed different degrees of gadolinium enhancement. CONCLUSIONS: Because earlier studies have revealed high incidences of meningiomatous bone infiltration in sphenoid wing meningiomas, and because infiltration was confirmed in four of our patients, we postulate that the gadolinium enhancement in the area of hyperostosis may be related to meningiomatous bone infiltration.

Navigation-guided opening of the internal auditory canal via the retrosigmoid route for acoustic neuroma surgery: cadaveric, radiological, and preliminary clinical study.

OBJECTIVE: We investigated the usefulness of a microscope-based navigational system (Multi Koordinaten Manipulator; Zeiss, Oberkochen, Germany) for removal of the posterior wall of the internal auditory canal (IAC) via the retrosigmoid route. METHODS: A cadaveric study was performed to assess the navigational localization error for the retrosigmoid approach to the IAC. Computed tomographic findings for 47 acoustic neuroma cases were divided into three groups, on the basis of the relationship between the labyrinth and the sigmoid-fundus line (medial, on the line, or lateral). Furthermore, the shortest distances between the most medial labyrinthine extension and the resection line were measured. In 20 acoustic neuroma operations, the different features and the practicality of the microscope-based navigational system for opening of the IAC were evaluated. RESULTS: The mean anatomic localization errors were 0.67 +/- 0.2 mm (95th percentile, 1.32 mm) for navigation to the IAC and 0.71 +/- 0.37 mm (95th percentile, 1.68 mm) for navigation to the posterior semicircular canal. The average distances between the most medial labyrinthine extension and the resection line were 3.65, 3.36, and 2.0 mm for the lateral, on-the-line, and medial groups, respectively. Direct contouring of structures at risk does not take into account the localization error, nor does it provide reliable navigational information. A novel indirect contouring concept that takes into account the localization error (the safety corridor method) was therefore introduced. CONCLUSION: The value of navigational assistance for opening of the IAC is promising but still limited. Further development is required before the clinical effects of this navigational approach can be evaluated.

Continuous infusion of proinflammatory cytokines into the brain to study brain cytokine induced local and systemic immune effects.

Proinflammatory cytokines are produced in the brain after various kinds of insult (ischemia, trauma, infection). In this process interleukin (IL)-1beta, IL-6 and tumor necrosis factor (TNF)-alpha are most important. These cytokines are key mediators of inflammation. Furthermore, these cytokines can act as neurotransmitters and develop direct effects on the central nervous system (CNS) including fever, sleep and stimulation of the neuroendocrine as well as sympathetic nervous system. Moreover, IL-1beta and TNF-alpha may also be involved in brain repair and regenerating processes. However, most of the data about the role of cytokines in the brain have been obtained from either in vitro studies or bolus injections into the brain parenchyma or cerebroventricular system. On the other hand, it is known that cytokines are released continuously into the brain after a cerebral insult over a period of 24 to 48 h. In order to further complete the knowledge about the interactions between neural and immune cells to overcome the primary insult and initiate repair and regeneration in the CNS, a new animal model of local inflammation reaction was established using chronic intracerebral infusion of rat recombinant cytokines.

Secondary abscess formation in pituitary adenoma after tooth extraction. Case report.

The presence of an abscess in a pituitary tumor is a very rare finding. The authors report the case of a 69-year-old man with a pituitary adenoma confirmed by neuroimaging results, in whom a high fever, meningismus, and left-sided ophthalmoplegia developed 4 days after tooth extraction. The results of serial cranial magnetic resonance imaging were highly indicative of an abscess formation within the pituitary adenoma. During surgery the tumor was approached transsphenoidally and removed. Histological examination confirmed the presence of an abscess formation within the pituitary adenoma. It is most likely that the tooth extraction caused a bacteremia, which led to an inflammation with abscess formation within the pituitary adenoma. The authors conclude that invasive dental procedures should be avoided before planned resection of a pituitary adenoma.

Role of bedside microdialysis in the diagnosis of cerebral vasospasm following aneurysmal subarachnoid hemorrhage.

OBJECT: Ischemia due to vasospasm is a feared complication in patients following aneurysmal subarachnoid hemorrhage (SAH). Cerebral online microdialysis monitoring may detect the metabolic changes in the extracellular fluid associated with ischemia. The aims of the present study were to correlate clinical course, microdialysis-recorded data, transcranial Doppler (TCD) ultrasonography findings, and angiographic findings in patients with SAH. METHODS: In 60 patients a microdialysis catheter was inserted into the brain parenchyma that is most likely to be affected by vasospasm directly after aneurysm clipping. Hourly analyses of glucose, pyruvate, lactate, and glutamate levels were performed using a bedside device. Blood-flow velocities were obtained using serial TCD measurements. Cerebral angiography was routinely performed on Day 7 after aneurysm clipping or earlier in cases of clinical deterioration (30 patients). In all patients the results of microdialysis monitoring, TCD ultrasonography, and angiography were correlated. The mean duration of monitoring was 7.3+/-2.5 days. In patients with acute ischemic neurological deficits (18 patients) immediate microdialysis-recorded alterations were observed if the probe was placed close to the malperfused region. In 13 of 15 patients with symptomatic vasospasm (delayed ischemic neurological deficit [DIND]), the microdialysis-recorded values revealed secondary deterioration. In terms of confirming DIND, microdialysis had the highest specificity (0.89, 95% confidence interval [CI] 0.78-1) compared with TCD ultrasonography (0.63, 95% CI 0.46-0.8) and angiography (0.53, 95% CI 0.35-0.7). For microdialysis, the positive likelihood ratio was 7.8, whereas this was significantly lower for TCD ultrasonography (1.7) and angiography (2.1). CONCLUSIONS: Although angiography also demonstrates vessel narrowing in asymptomatic patients, online microdialysis reveals characteristic metabolic changes that occur during vasospasm. Thus, online microdialysis may be used to confirm the diagnosis of vasospasm.

Monitoring of cerebral oxygenation in patients with severe head injuries: brain tissue PO2 versus jugular vein oxygen saturation.

Monitoring of cerebral oxygenation is considered to be of great importance in minimizing secondary hypoxic and ischemic brain damage following severe head injury. Although the threshold for cerebral hypoxia in jugular bulb oximetry (measurement of O2 saturation in the jugular vein (SjvO2)) is generally accepted to be 50% oxygen saturation, a comparable value in brain tissue PO2 (PtiO2) monitoring, a new method for direct assessment of PO2 in the cerebral white matter, has not yet been established. Hence, the purpose of this study was to compare brain PtiO2 with SjvO2 in severely head injured patients during phases of reduced cerebral perfusion pressure (CPP) to define a threshold in brain PtiO2 monitoring. In addition, the safety and data quality of both SjvO2 and brain PtiO2 monitoring were studied. In 15 patients with severe head injuries, SjvO2 and brain PtiO2 were monitored simultaneously. For brain PtiO2 monitoring a polarographic microcatheter was inserted in the frontal cerebral white matter, whereas for SjvO2 measurements were obtained by using a fiberoptic catheter placed in the jugular bulb. Intracranial pressure was monitored by means of an intraparenchymal catheter. Mean arterial blood pressure, CPP, end-tidal CO2, and arterial oxygen saturation (pulse oximetry) were continuously recorded. All data were simultaneously stored and analyzed using a multimodal computer system. For specific analysis, phases of marked deterioration in systemic blood pressure and consecutive reductions in CPP were investigated. There were no complications that could be attributed to the PtiO2 catheters, that is, no intracranial bleeding or infection. The "time of good data quality" was 95% in brain PtiO2 compared to 43% in SjvO2; PtiO2 monitoring could be performed twice as long as SjvO2 monitoring. During marked decreases in CPP, SjvO2 and brain PtiO2 correlated closely. A significant second-order regression curve of SjvO2 versus brain PtiO2 (p < 0.01) was plotted. At a threshold of 50% in SjvO2, brain PtiO2 was found to be within the range of 3 to 12 mm Hg, with a regression curve "best fit" value of 8.5 mm Hg. There was a close correlation between CPP and oxygenation parameters (PtiO2 and SjvO2) when CPP fell below a breakpoint of 60 mm Hg, suggesting intact cerebral autoregulation in most patients. This study demonstrates that monitoring brain PtiO2 is a safe, reliable, and sensitive diagnostic method to follow cerebral oxygenation. In comparison to SjvO2, PtiO2 is more suitable for long-term monitoring. It can be used to minimize episodes of secondary cerebral maloxygenation after severe head injury and may, hopefully, improve the outcome in severely head injured patients.

Effect of cerebral perfusion pressure on contusion volume following impact injury.

OBJECT: Although it is generally acknowledged that a sufficient cerebral perfusion pressure (CPP) is necessary for treatment of severe head injury, the optimum CPP is still a subject of debate. The purpose of this study was to investigate the effect of various levels of blood pressure and, thereby, CPP on posttraumatic contusion volume. METHODS: The left hemispheres of 60 rats were subjected to controlled cortical impact injury (CCII). In one group of animals the mean arterial blood pressure (MABP) was lowered for 30 minutes to 80, 70, 60, 50, or 40 mm Hg 4 hours after contusion by using hypobaric hypotension. In another group of animals the MABP was elevated for 3 hours to 120 or 140 mm Hg 4 hours after contusion by administering dopamine. The MABP was not changed in respective control groups. Intracranial pressure (ICP) was monitored with an ICP microsensor. The rats were killed 28 hours after trauma occurred and contusion volume was assessed using hematoxylin and eosin-stained coronal slices. No significant change in contusion volume was caused by a decrease in MABP from 94 to 80 mm Hg (ICP 12+/-1 mm Hg), but a reduction of MABP to 70 mm Hg (ICP 9+/-1 mm Hg) significantly increased the contusion volume (p < 0.05). A further reduction of MABP led to an even more enlarged contusion volume. Although an elevation of MABP to 120 mm Hg (ICP 16+/-2 mm Hg) did not significantly affect contusion volume, there was a significant increase in the contusion volume at 140 mm Hg MABP (p < 0.05; ICP 18+/-1 mm Hg). CONCLUSION: Under these experimental conditions, CPP should be kept within 70 to 105 mm Hg to minimize posttraumatic contusion volume. A CPP of 60 mm Hg and lower as well as a CPP of 120 mm Hg and higher should be considered detrimental.

Brain tissue pO2-monitoring in comatose patients: implications for therapy.

Monitoring of brain tissue partial pressure of O2 (ti-pO2) is a promising new technique that allows early detection of impending cerebral ischemia in brain-injured patients. The purpose of this study was to investigate the effects of standard therapeutic interventions used in the treatment of intracranial hypertension in comatose patients on cerebral oxygenation. In the neurosurgical intensive care unit ti-pO2, arterial blood pressure, intracranial pressure (ICP), cerebral perfusion pressure (CPP) and jugular bulb oxygen saturation (SjvO2) were prospectively studied (0.1 Hz acquisition rate) in 23 comatose patients (21 with severe traumatic brain injury, 2 with intracerebral hematoma) during various treatment modalities: elevation of CPP with dopamine (n = 35), lowering of the head (n = 22), induced arterial hypocapnia (n = 13), mannitol infusion (n = 16), and decompressive craniotomy (n = 1). Ischemic episodes ('IE' = ti-pO2 < 10 mmHg for > 15 min) within the first week after the insult were always associated with unfavorable neurological outcome. Elevation of CPP from 32 +/- 2 to 67 +/- 4 mmHg significantly improved ti-pO2 by 62% (13 +/- 2 to 21 +/- 1 mmHg) and reduced ICP indicating intact cerebral autoregulation. Further raising CPP from 68 +/- 2 to 84 +/- 2 mmHg did not alter ti-pO2. Mannitol-induced ICP reduction from 23 +/- 1 to 16 +/- 2 mmHg did not affect ti-pO2, nor did lowering of the head from 30 degrees to 0 degree. Hyperventilation from an endtidal pCO2 of 29 +/- 3 to 21 +/- 3 mmHg normalized ICP and CPP, but significantly reduced ti-pO2 from 31 +/- 2 to 14 +/- 3 mmHg. Decompressive craniotomy in a 15-year old patient with refractory intracranial hypertension instantly restored ti-pO2. Based on the present data, our understanding of many interventions previously believed to improve brain oxygenation might have to be re-evaluated. A CPP > 60 mmHg emerges as the most important factor determining sufficient brain tissue pO2. Any intervention used to further elevate CPP does not improve ti-pO2, to the contrary, hyperventilation even bears the risk of inducing brain ischemia.

Lymphocytic hypophysitis simulating a pituitary adenoma in a nonpregnant woman.

Lymphocytic adenohypophysitis can cause pituitary expansion and hypopituitarism closely mimicking the features of a pituitary adenoma. In contrast to pituitary adenoma, lymphocytic adenohypophysitis occurs almost exclusively in young women in relation to pregnancy. We report a case of a 43-year-old nonpregnant nullipara who exhibited an intrasellar mass with diffuse homogeneous contrast enhancement on magnetic resonance imaging scanning. Serum hormone analyses revealed secondary hypoadrenalism, hypothyroidism, and hypogonadism. The patient underwent surgery for a presumed nonsecreting pituitary adenoma. Histopathological examination showed extensive infiltration of the anterior pituitary gland by chronic inflammatory cells. The immunohistochemical pattern of the inflammatory cells indicated the chronic and putatively autoimmune nature of the disease.

[MRI of the cervical spine using T1-weighted multislice FLASH sequences]. / MRT der Halswirbelsäule mit T1-gewichteten mehrschichtfähigen FLASH-Sequenzen.

A study has been carried out to evaluate contrast and image quality of cervical structures using multislice 2D-flash sequences with long repetition times (TR = 400 ms.) and short echo delay times (TE = 5.8 ms.). The examinations were carried out using ten normals with an MRI of 1.5 Tesla and flip angles of 10, 20, 30, 50, 70 and 90 degrees. The best contrast between intervertebral disc and surrounding tissue was obtained between 50 and 70 degrees, best contrast between compact bone and CSF with 10 degrees. In order to demonstrate degenerative changes of the cervical spine, it appears sensible to use a combination of these angles. The described sequences produce good images of the cervical structures with little image degradation. Compared to T1-weighted spin-echo sequences, the method has a number of significant advantages, such as variations in image contrast, higher maximal number of slices, contiguous imaging and less imaging time.

["Surgical projection" in the gadolinium-DTPA (Gd-DTPA)-supported NMR tomographic diagnosis of lateral lumbar disk prolapse]. / Die "chirurgische Projektion" in der Gadolinium-DTPA(Gd-DTPA)-unterstützten kernspintomographischen Diagnostik des lateralen lumbalen Bandscheibenvorfalls.

In a group of 25 patients the coronal views of plain and Gd-DTPA-enhanced MRI studies were correlated with CT and operative findings. All series included sagittal, transverse and coronal FLASH sequences (GE 500/6, flip angle 70 degrees), sagittal proton density-(SE 2500/15) and T2-(SE 2500/70) weighted images. MR diagnosis proved to be correct in all cases. Compared to CT and axial MRI herniated disk material in the lateral intravertebral space and its relationship to nerve roots was demonstrated more clearly on coronal views.

[A 3-dimensional reconstructive procedure in lumbar computed tomography]. / Dreidimensionale Rekonstruktionsverfahren in der lumbalen Computertomographie.

In this study, 50 patients were examined by a Siemens' "Somatom Plus"; continuous 2 mm sections between the third lumbar and first sacral vertebra were obtained. The accuracy of the 3-D reconstruction software programme was checked by measuring a polyethylene phantom of a second lumbar vertebra. Reconstruction was carried out with a threshold definition of 150 Hu. In each case, four standard projections and medio-sagittal, medio-lateral and coronary sections were reconstructed, photographed and compared with axial CT sections and conventional radiographs. All these imaging procedures were suitable for the diagnosis of osteochondrosis and chondrosis. Spondylosis was diagnosed more frequently on 3-D CT. Spondylarthrosis, with narrowing of the intervertebral foramina and root canals is shown particularly well by 3-D CT, since the entire extent of these structures can be seen. 3-D surface reconstruction of the lumbar spine is useful in the diagnosis of lumbar spondylarthrosis with narrowing of the root canals and of the spinal canal. This method of axial Ct is superior to conventional radiography of the lumbar spine in the usual two planes.

[Cerebral aneurysms: their 3-dimensional imaging with spiral CT]. / Zerebrale Aneurysmen: dreidimensionale Darstellung mit der Spiral-CT.

In this study, the possibility of non-invasive, three-dimensional demonstration of aneurysms of the basal cerebral arteries by means of spiral CT was investigated. The first step was to obtain exact definition of optimal examination parameters. Angio CTs at appropriate levels were performed on 10 subjects and time/density curves of the arterial and venous phases obtained in order to optimise the beginning of the arterial spiral CT series. The second step in this investigation was to examine 7 patients; in 6 of these basal aneurysms had been demonstrated by DSA. By means of multiplanar three-dimensional reconstruction from the data of the spiral CT it was possible to demonstrate 7 aneurysms with a diameter between 5 and 18 mm. Their position and relationship to the bony skull was also shown.

[MRT in cervical disk herniation: plain vs. contrast-enhanced images]. / MRT bei zervikalen Bandscheibenvorfällen: native vs. kontrastmittelunterstützte Aufnahmen.

Aim of this study was to assess the value of Gd-DTPA administration in MRI of cervical disk herniations. In 34 patients, showing 40 cervical disk herniations, plain proton density- and T1-weighted as well as contrast-enhanced T1-weighted 2D-FLASH images were generated. Contrast between the herniated material and the CSF already was sufficient without administration of Gd-DTPA in all cases. Sufficient contrast between the herniations and the intraforaminal structures was obtained in 13/40 cases and 40/40 cases on plain and contrast-enhanced images, respectively. Definition of the herniated disks was judged to be sufficient in 30/40 cases on plain images and 40/40 cases on contrast-enhanced images. The diagnostic value of the images was improved in 3/12 lateral and 7/8 intraforaminal herniations by contrast administration, whereas there was no significant increase in diagnostic value in posterior or posterolateral herniations. As a result, Gd-DTPA administration is recommended if definition of lateral and intraforaminal disk herniations in MRI is poor.

[Cerebral arteriovenous angiomas: 3-dimensional demonstration by spiral CT]. / Zerebrale a.v. Angiome: Dreidimensionale Darstellung mit der Spiral-CT.

In 20 patients with known or suspected supratentorial arteriovenous malformations, an attempt was made to see how far CT angiography with 3-dimensional reconstructions is able to make a diagnosis and to differentiate the various components of the angioma. Spiral CT was performed following an intravenous bolus injection of 60-80 ml of iodine containing contrast medium. In all patients the diagnosis was confirmed by intra-arterial DSA of the vertebral vessels. In 13 patients, av malformations could be diagnosed following multiplanar 3-D reconstructions which agreed with the findings on DSA. The large supplying vessels, the nidus and the large draining veins could be defined with certainty. In 6 patients follow-up examination after embolisation was performed. The results could be demonstrated in three dimensions and the success of treatment could be documented unequivocally. CT angiography with 3-D reconstruction is able to supply important information in the majority of intracranial av malformations, both during initial investigation and following treatment.