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Background: Conventional magnetic resonance (MR) imaging has a number of limitations in the diagnosis of the most common intracranial brain tumors, including tumor specification and the detection of tumoral infiltration in regions of peritumoral edema. Purpose: To prospectively assess if diffusion-weighted MR imaging (DWI) could be used to differentiate between different types of brain tumors and to distinguish between peritumoral infiltration in high-grade gliomas, lymphomas, and pure vasogenic edema in metastases and meningiomas. Material and Methods: MR imaging and DWI was performed on 93 patients with newly diagnosed brain tumors: 59 patients had histologically verified high-grade gliomas (37 glioblastomas multiforme, 22 anaplastic astrocytomas), 23 patients had metastatic brain tumors, five patients had primary cerebral lymphomas, and six patients had meningiomas. Apparent diffusion coefficient (ADC) values of tumor (enhancing regions or the solid portion of tumor) and peritumoral edema, and ADC ratios (ADC of tumor or peritumoral edema to ADC of contralateral white matter, ADC of tumor to ADC of peritumoral edema) were compared with the histologic diagnosis. ADC values and ratios of high-grade gliomas, primary cerebral lymphomas, metastases, and meningiomas were compared by using ANOVA and multiple comparisons. Optimal thresholds of ADC values and ADC ratios for distinguishing high-grade gliomas from metastases were determined by receiver operating characteristic (ROC) curve analysis. Results: Statistically significant differences were found for minimum and mean of ADC tumor and ADC tumor ratio values between metastases and high-grade gliomas when including only one factor at a time. Including a combination of in total four parameters (mean ADC tumor, and minimum, maximum and mean ADC tumor ratio) resulted in sensitivity, specificity, positive (PPV), and negative predictive values (NPV) of 72.9, 82.6, 91.5, and 54.3% respectively. In the ROC curve analysis, the area under the curve of the combined four parameters was the largest (0.84), indicating a good test. Conclusion: Our results suggest that ADC values and ADC ratios (minimum and mean of ADC tumor and ADC tumor ratio) may be helpful in the differentiation of metastases from high-grade gliomas. It cannot distinguish high-grade gliomas from lymphomas, and lymphomas from metastases. ADC values and ADC ratios in peritumoral edema cannot be used to differentiate edema with infiltration of tumor cells from vasogenic edema when measurements for high-grade gliomas, lymphomas, metastases, and meningiomas were compared.

Sixteen former rayon viscose workers were investigated four years after the exposure to carbon disulfide was discontinued. Median age was 58 years (range 43-65 years), median exposure time was 17 years (range 10-35 years). Encephalopathy was diagnosed in altogether 14 workers. To further explore pathophysiological mechanisms, cerebrovascular investigations were employed. Doppler ultrasound examination of the precerebral vessels in 15 workers showed a slight stenosis of the left internal carotid artery in one. Regional cerebral blood flow investigation (rCBF) with single photon emission computerized tomography (SPECT) with Xenon-133 gas was performed in 14. There was no significant difference from a control group. Regional side-to-side asymmetries beyond reference limits were demonstrated in eight workers. The abnormalities were modest, but may indicate a tendency toward focal blood flow disturbances in workers with long-term exposure to carbon disulfide.

Background – In Norway, there are approximately 16000 strokes each year and 15% of these are caused by intracerebral hematomas. Intracerebral hemorrhage (ICH) results from the rupture of blood vessels within the brain parenchyma. ICH occurs as a complication of several diseases, the most prevalent of which is chronic hypertension. When hemorrhage develops in the absence of a pre-existing vascular malformation or brain parenchymal lesion, it is denoted primary ICH. Secondary ICH refers to hemorrhage complicating a pre-existing lesion. Primary ICH is the most common type of hemorrhagic stroke, accounting for approximately 10% of all strokes. Despite aggressive management strategies, the 30-day mortality remains high, at almost 50%, with the majority of deaths occurring within the first 2 days. At 6 months, only 20–30% achieve independent status. Material and methods – This article is based on clinical experience, modern therapeutic guidelines for the treatment of intracerebral hematomas and up-to-date medical literature found in Medline. The article discusses the pathophysiology, clinical aspects, treatment, and the prognosis of intracerebral hematomas. Results and discussion – Advances in diagnosis, prognosis, pathophysiology, and treatment over the past few decades have significantly advanced our knowledge of ICH; however, much work still needs to be carried out. Future genetic and epidemiologic studies will help identify at-risk populations and hopefully allow for primary prevention. Randomized controlled studies focusing on novel therapeutics should help to minimize secondary injury and hopefully improve morbidity and mortality.

Background: Osteoporotic sacral insufficiency fractures are usually spontaneous or caused by discrete traumas. The fluoroscopic anatomy of the sacrum can be difficult to understand, and this is why sacroplasty is considered more challenging than ordinary vertebroplasties. Purpose: To demonstrate the planning of the procedure and the effectiveness of treatment with sacroplasty by means of three-dimensional computed tomography (3D CT) by combining multiplanar reconstructions (MPR) and volume-rendering technique (VRT). Material and Methods: Five elderly, osteoporotic patients with intense pelvic and hip pain underwent weeks of inconclusive clinical and radiological diagnostic efforts. Correct diagnosis was finally attained with magnetic resonance imaging (MRI) and CT. Plain radiographs rarely show fractures, and MR or CT examinations are necessary to demonstrate longitudinal fractures. The procedures were performed with digital biplane equipment using preoperative 3D CT planning procedures. Polymethyl methacrylate (PMMA) was injected to fill the fracture sites. Results: The fractures were successfully treated with sacroplasty using PMMA. A new technique, which involves placing the needles along the long axis of the sacrum, was optimized to the individual patients’ fractures and sacral anatomy by meticulous planning on a workstation with 3D CT data sets. It was technically successful in all five cases. Four of the five patients had sustained pain relief. Conclusion: Sacral insufficiency fractures are not uncommon and should be considered in the elderly population with low back pain. Sacroplasty using the optimized “long-axis technique” gave almost immediate pain relief for all five patients in our study material. No complications were observed.

Purpose: To demonstrate the importance of magnetic resonance (MR) and computed tomography (CT) in the evaluation of cervical traumas in patients suffering from ankylosing spondylitis. Material and Methods: Eleven patients with advanced ankylosing spondylitis were admitted to neurosurgical treatment after trauma to the neck region. All had neurological symptoms and were evaluated with plain X‐ray, CT, and MR. Results: CT with reformation sagittal and coronal plane was superior to plain X‐ray films in demonstrating fractures and dislocations. MR was considered mandatory when evaluating changes in medulla and epidural hematomas, which were detected in 4 patients. The clinical outcome was poor in 5 patients and good in 6. The poorest outcome was seen in patients with cord contusion and epidural hematoma. Conclusion: We conclude that plain X‐ray is of no greater importance in the acute phase of highest value in follow‐up evaluation of the healing process and final position of the fractured vertebrae. Our protocol in the acute phase in traumatized ankylopoetic patients consists of lateral conventional X‐ray, CT with reformatted images, and MR, the last‐mentioned being important in detecting epidural hematoma that reduces the clinical outcome further if not removed. In our opinion, MR must be part of the radiological protocol following neck traumas in all patients with ankylosing spondylitis.

Purpose: Intra-arterial digital subtraction angiography (DSA) has been considered the gold standard examination in the follow-up of patients treated with Guglielmi detachable coils (GDCs). However, DSA is an invasive and expensive investigation and results in exposure to ionising radiation to both patient and operator. The aim of this study was to compare MR angiography (MRA) with DSA with regard to patency of the occlusion of aneurysms following GDC treatment. Material and Methods: We performed 75 MRA and DSA examinations on 51 patients treated with GDCs. The examinations were performed 3-36 months after embolisation and the interval between MRA and DSA was less than 1 week. Hard copies of both studies were interpreted retrospectively and independently for residual flow within the aneurysm, residual aneurysmal neck, and parent and branch vessel flow. Results: Patency status of parent and branch vessel flow was correctly identified with MRA in all patients except 1. The sensitivity of MRA in revealing residual flow within the aneurysm was 97%. The specificity in ruling out residual flow within the aneurysm was 91%. Conclusion: MRA may replace DSA in the long-term follow-up of coiled cerebral aneurysms. The initial follow-up examination should, however, include both modalities.

Purpose: Minimal- or non-invasive methods replacing intra-arterial digital subtraction angiography (IA-DSA) would be of great importance in patients suffering from acute subarachnoid haemorrhage (SAH). The aims of this study were to compare CTA with IA-DSA in patients with acute SAH, to compare CTA interpretations with those of blinded, independent reviewers and to evaluate improvement in CTA diagnostics after 1 year of experience with CTA. Material and Method: During 2 years 162 patients with SAH underwent CTA as well as IA-DSA. Independent blinded review of 77 patients was performed for 1 year. Results: Totally 144 aneurysms were demonstrated in 119 patients at IA-DSA, while 43 patients had normal intracranial arteries. Initially 131 aneurysms were detected at CTA while 2 normal, tortuous arteries were misinterpreted as aneurysms, giving a sensitivity of 91% and a specificity of 95%. At independent blinded review the observer agreement was 87% and the kappa value 0.68. Conclusion: CTA in SAH is of great value in demonstrating vascular anatomy and the exact size of an aneurysm. However, IA-DSA is still needed for diagnostic evaluation in aneurysms smaller than 5 mm in diameter, especially in those located near bony structures.

The aim of this study was to evaluate the efficacy of contrast-medium (CM)-enhanced MR imaging of operated pituitary macroadenomas with reduced dose of gadopentetate dimeglumine. In a prospective study 18 patients were examined with coronal T1-weighted MR imaging prior to and following intravenous CM injections. Two sets of contrast-enhanced coronal images were obtained in each patient; the first set after 50 % of the recommended dose of 0.1 mmol/kg body weight (b. w.) had been administered, and the second set immediately after additional CM had been given to make up a total dose of 0.1 mmol/kg b. w. The images were evaluated by three neuroradiologists. The SIPAP classification system was used to evaluate tumour extension, whereas tumour margin conspicuity was scored using an arbitrary scale of 1–5 (1 = indistinct, 5 = well defined). Signal intensity measurements obtained from the most enhancing part of the adenomas demonstrated increased enhancement with increased CM dose. Tumour delineation scores were significantly better on the reduced- and full-dose images than on pre-CM injection images, but, with one exception, tumour extension was identified as the same on all imaging sequences. Postoperative MR imaging of large macroadenoma residues can routinely be performed without intravenous CM. When CM is indicated a reduced dose of gadopentetate dimeglumine should provide sufficient diagnostic information.

The purpose of this article is to provide an overview of all aspects concerning interventional neuroradiology of vascular central nervous diseases. Today, interventional neuroradiology can help many patients that, even until a few years ago, did not have any possibility for a safe cure. Complex cerebral arteriovenous malformations and fistulas, inoperable aneurysms and intravascular thromboses are often treated with interventional neuroradiology alone, while in other cases a combination of neurosurgery and radiation may help in reaching a good outcome for the patients. In the past few decades the efforts by neuroradiologists and collaborating clinicians to develop treatment strategies and methods for these and other high risk diseases represent a vast, fascinating field of modern medicine. The article therefore focusses on the state-of-the-art and describes presently used methods for diseases that can be treated with interventional neuroradiology. Literature dealing with the historical development of interventional neuroradiology and important publications of recent scientific work are reviewed, providing the reader with an overview of the most pertinent material on each disease discussed. Aspects of training and ethics are discussed and emphasis is focussed on the importance of recognizing these aspects as essential in any case of interventional radiological treatment.

A 7-year-old girl with a right-sided congenital arteriovenous fistula in the neck was admitted with signs of cardial incompensation. Her fistula was fed from the right vertebral artery in antegrade as well as retrograde directions. A steal from the intracranial arteries was established. In addition, smaller feeding arteries from the neck were found. She was operated on with ligation of the right vertebral artery proximal to the fistula but the attempted ligation of the artery cranially to the fistula was unsuccessful. She was therefore embolized by the formation of a plug of platinum fiber coils in the upper right vertebral artery. Catheterization was performed from the left vertebral artery via the basilar artery. Persisting minor feeders to the fistula from cervical arteries were embolized in a second session. Finally, surgical extirpation of the fistula was performed together with the operative ligation of a crossover feeding artery from the left vertebral artery. Her heart size, heart rate and blood pressure were successively normalized.

In order to assess changes occurring to lumbar disk herniations and bulges and to the disk spaces after conservative treatment, a follow-up CT was carried out of 106 pathologic disks in 92 patients at a mean interval of 14 months after the initial examination. There was a strong association between the evolution of the hernias and clinical results, with a decrease in size of the majority of hernias in successfully treated patients, whereas the others essentially remained unchanged (p < 0.0001). A significantly higher proportion of large hernias diminished as compared to the smaller ones (p < 0.0001). Diffuse disk bulges were associated with a poor outcome and never regressed. There was a lower incidence of diminution of the central hernias compared to other locations. Patients with normal disk space at the initial examination had a better outcome than those with disk space narrowing. Only occasionally was a reduction of the disk space observed at follow-up.

In order to assess changes occurring in disk hernias and disk spaces following percutaneous nucleotomy a follow-up CT was carried out an average of 6 months after treatment of 69 disks in 60 patients. Forty-three of the disks were also reexamined at an average of 11 months after the first follow-up. Twenty-seven percent of the hernias were reduced in size at the first follow-up. Fourteen percent were reduced and 7% had increased between the first and second follow-ups. The medium-sized and large hernias were more frequently reduced compared to the smaller ones. Reduction of the disk space was found in 29% of the cases at first follow-up. An additional 24% were reduced between the first and second follow-ups. No association was demonstrated between change in size of the herniation or disk space and clinical outcome or amount of nucleous material removed at nucleotomy.

We prospectively evaluated a diagnostic and therapeutic procedure combining superselective angiography, endovascular embolisation and surgery in arteriovenous malformations (AVM) of the brain. Our aim was to achieve the best possible result exposing the patients to the lowest possible risk. During a 3 year period 48 patients were studied, of whom 22 (46%) were treated by incomplete preoperative embolisation and subsequent complete surgical removal of the AVM. All angiography and embolisations were performed with the Tracker catheter system using polyvinyl alcohol particles and/or platinum fibre coils. The other 26 patients were treated as follows: incomplete embolisation in 11 (23%), complete embolisation in 2 (4%), angiography and surgery in 3 (6%) and combined embolisation and radiation in 7 (15%); 3 patients were excluded from any therapy after superselective angiography. The total number of acute complications and permanent sequelae were 8 (17%) and 3 (6%) respectively. We concluded that superselective cerebral angiography, a relatively safe procedure, should play an important role in deciding treatment strategies for AVMs of the brain. The risks of combined embolisation and surgery are probably lower than those of either alone. In a few cases surgery or embolisation alone carries an unequivocally lower risk, and combined therapy is not justifiable.

Twelve patients with known or suspected pituitary lesions underwent MR imaging with gadodiamide injection at a dose of 0.1 (n = 5) or 0.3 (n = 7) mM/kg. Six of the patients were also studied with 0.1 mM/kg gadopentetate dimeglumine. Consistent with previous reports gadodiamide injection was found to be a safe and effective contrast medium for MR imaging of the pituitary region. No additional diagnostic information was obtained using 0.3 mM/kg gadodiamide injection compared to 0.1 mM/kg gadopentetate dimeglumine in the same patients. The high dose (0.3 mM/kg) gadodiamide injection in 7 patients did not shorten the T2 value sufficiently to overwhelm the T1 shortening and leave pathologic lesions hypointense compared to precontrast studies. With the comparable relaxivities of gadodiamide injection and gadopentetate dimeglumine, similarities in results have to be expected when using these media for MR image enhancement.

A traumatic carotid-cavernous fistula was closed with a silicone detachable balloon. Prior to the closure of the fistula, clinical and transcranial Doppler testing was performed in order to evaluate the consequences of a possible occlusion of the carotid artery. A newly developed Doppler technique with bilateral simultaneous velocity recordings of the middle cerebral arteries was useful during the procedure. The detachable balloon was effective in closing the fistula, but collapse of the balloon and the development of an extradural aneurysm was found at control examinations.

In order to reduce the recanalization rate of arteriovenous malformations and multiple dural arteriovenous fistulas, embolization was carried out with polyvinyl alcohol (PVA) particles combined with platinum fibre coils in 20 patients. The malformation was occluded more effectively than by PVA alone. Distal deposition of the emboli was obtained by improved steerable catheters (Tracker-18-unibody) and guidewires. The complication rate was lower than usually reported from studies using glue as embolic agent. It was concluded that the combination of PVA and fibre coils enhances the safety and effectiveness of embolization therapy and reduces the frequency of recanalization of intracranial AVMs.

MR findings before and after transsphenoidal surgery were evaluated in 6 cases. T1-weighted (TR/TE 600/20) sagittal and coronal images with 2 or 4 acquisitions were obtained, using 3-mm slice thickness and 0.3-mm interslice gaps. Of 18 MR examinations, 13 included coronal i.v. contrast medium enhanced images. Image quality, sinus cavernosus invasion, identification of normal pituitary tissue and tumor size were examined. All MR studies clearly demonstrated the macroadenomas whether 2 or 4 acquisitions were used, and whether i.v. contrast medium was administered or not. Surgically confirmed sinus cavernosus infiltration was seen in 4 patients. The pituitary stalk was identified separate from the tumor in 2 patients, and the gland in one. There was reduction in tumor size over time, indicating that final radiologic assessment after transsphenoidal surgery is best performed 4 to 6 months postoperatively. It should not be necessary to routinely include i.v. contrast medium injection in the postoperative evaluation of macroadenomas.

Seven healthy volunteers underwent coronal MR imaging at 1.5 tesla of the normal 3rd, 4th, and 5th lumbar, and 1st sacral nerve roots. Coronal slices, 3-mm-thick with a 0.3-mm gap between the slices were obtained (TR/TE 600/22) through the lumbar spinal canal. All the nerve roots were visible on at least one image. One can routinely expect to demonstrate the 3rd, 4th, and 5th lumbar, and 1st sacral nerve roots on T1-weighted, 3-mm-thick coronal MR scans. We found no correlation between the degree of lumbar lordosis and the lengths of the visible nerve roots. Five patients with one of the following spinal problems: anomaly, tumor, disk herniation, and failed back surgery syndrome were examined according to our protocol. In all these cases coronal MR imaging gave the correct diagnosis.

Experience with neuroradiological endovascular therapy in a small country is presented. Five Norwegian university hospitals are currently performing coiling of cerebral aneurysms and three are embolizing cerebral arteriovenous malformations. The small number of procedures in most of these institutions may threaten the quality of treatment, education of neuroinradiologists, research and scientific work in this field. An even greater concern might arise in the field of neurosurgery after the reduction in surgical procedures following the increasing takeover by endovascular procedures. The safety during transportation of patients with subarachnoid hemorrhage has been debated and is considered by some as a problem, but earlier experience from Nordic countries does not support this concern. Reducing the number of centres performing these procedures seems necessary to obtain adequate patient safety and an ethical practice.

To overcome the technical limitations which have precluded noninvasive Doppler ultrasound in investigation of rapid cerebral haemodynamic responses in two cerebrovascular beds at the same time, we have modified a commercial 2 MHz pulsed Doppler instrument with online spectrum analysis. Two probes are activated intermittently, recording eight averaged Doppler-shifted spectra from each probe sequentially. Concurrent recordings of blood velocity in both middle cerebral arteries were performed during 25 selective iohexol carotid angiography runs in 13 patients with near normal cerebral vasculature. The technique permitted the differentiation between the specific responses confined to the recipient vascular bed, and the general responses occurring in remote brain areas as well. The specific response to iohexol was biphasic; a significant decrease in blood velocity occurred less than 4 s after the bolus entry, probably due to the high viscocity of iohexol. Between 4 and 12 s. blood velocity was significantly increased, reflecting the cerebrovascular response to hypertonic solutions. The blood velocity on the opposite side increased from less than 4 s through 45 s after iohexol. This concurs with studies using electromagnetic flowmetry, and suggests that these general responses are elicited by anxiety, discomfort and pain. Thus, no general responses were seen during angiography under general anaesthesia. Eight patients investigated during catheter flushing with normal saline showed a biphasic specific response reciprocal to that due to iohexol. A significant blood velocity peak occurred less than 4 s after the bolus entry, followed by a decrease between 4 and 60 s. The saline injections produced no pain and evoked no significant general response.

Following a head trauma in a 40-year-old male, massive subarachnoid hemorrhage and fractures of the skull base/clivus was found at CT. CT angiography demonstrated an aneurysm on the proximal part of the right superior cerebellar artery. The aneurysm was successfully coiled without any complication and the patient improved clinically during the following three months. The decline in use of angiography in head trauma patients during the last two decades may lead to a lower detection of traumatic aneurysm than in previous times. The value of angiographic procedures in patients suffering head traumas with SAH and skull base fractures is therefore emphasized.

A 13-year-old girl with Klippel-Trenaunay-Weber syndrome and intradural extramedullary spinal arteriovenous fistulas is presented. Pre-embolization balloon test occlusions and embolization with platinum fibre coils were carried out in three sessions, after which the myelopathy and the intense back pain disappeared. Our conclusion is that spinal fistulas can be safely and effectively treated with fibre coils in combination with balloon testing.

Strokes in patients with atrial fibrillation are often due to large middle cerebral artery (MCA) infarctions, caused by cardiogenic emboli. The purpose of this study was to characterise the large MCA infarctions and to describe the prevalence and prognostic value of the hyperdense middle cerebral artery sign (HMCAS) in patients with atrial fibrillation.The patient material comprised all 449 patients included in a randomised clinical trial of low molecular-weight heparin versus aspirin in patients with acute ischaemic stroke and atrial fibrillation. Patients with Scandinavian Stroke Scale score8 were excluded. CT was performed on admission and at day 7, and was evaluated blinded to clinical data. The CT findings on admission were related to functional outcome at 14 days and 3 months, and incidence of cerebral haemorrhage within 7 days.Altogether 66/449 (15%) of the patients had large MCA infarctions. These patients had poorer clinical outcomes, and a higher frequency of haemorrhage on control CT within 7 days (15/59, 26% vs. 43/368, 12%). The HMCAS was found in 32/449 (7%) of the patients. It was significantly more frequent in patients with large MCA infarctions (17/66, 26% vs. 15/383, 4%), and was found most frequently within the first few hours following stroke onset. The HMCAS was associated with poor clinical outcomes and a higher frequency of cerebral haemorrhage, but these effects were partially explained by a preponderance of other risk factors in the HMCAS group.Large MCA infarction is a frequent finding in patients with atrial fibrillation. These patients have a high prevalence of the HMCAS, which is an early infarction sign and a marker of a poor prognosis.

Magnetic resonance tomography is considered the most important technique in modern neuroradiology. This article demonstrates the importance of MR imaging in the diagnosis of diseases of the central nervous system. Modern neuroradiology is completely dependent upon this modality, and sections and departments of neuroradiology should have great responsibility for both diagnostic MR imaging and the day-to-day operation MR laboratories.

In one year three patients were operated on for spinal haematomas following thoracic epidural analgesia. All three patients experienced back pain and developed progressive paraparesis, one in connection with insertion of the catheter and two after its removal. A spinal block was visualized using MRI in two patients and myelography in one. The patients were operated on with posterior decompression. In two patients an epidural haematoma was evacuated. Both patients recovered neurologic function, one completely. The third patient, who had a subarachnoidal hemorrhage and an intramedullar haematoma, remained paralytic.

Four patients with basilar artery fenestration aneurysms at the vertebro basilar junction were admitted after subarachnoid haemorrhage. In two of them attempted surgery failed. Subsequently, all four were embolised with Guglielmi Detachable Coils (GDC), three of them in the acute phase. In one case the initial embolisation was incomplete, but follow-up angiography demonstrated spontaneous total occlusion. In another, partial reopening was treated with further embolisation. Three patients recovered completely after treatment. One patient still has deficits related to surgery of an accompanying aneurysm at the middle cerebral artery. He is clinically improving but still not back at work. In two cases the fenestration was combined with a hypoplastic upper vertebral artery on one side. A hypoplastic veretebral artery on one side may frequently be part of the developmental anomaly of basilar fenestration aneurysms. The anatomical configuration and location of these aneurysms is such that their true nature is sometimes difficult to disclose at cerebral angiography and is only realised during embolisation. Treatment with GDC coils seems superior to surgery in basilar artery fenestration aneurysms.

Treatment of cerebral aneurysms with Guglielmi Detachable Coils (GDC) was performed for the first time in Scandinavia in 1992. The experience at Ullevål University Clinic from 1994 to 1996 comprises 27 surgically inoperable aneurysms. Successful embolization was performed in 20 patients. No complications were seen during the procedure. However, renewed bleeding with fatal outcome occurred in one patient. In accordance with other colleagues we consider this treatment to be unsuitable for wide neck aneurysms (5 mm). For this reason seven patients were not treated. We conclude that GDC embolization seems to be an effective therapy for selected inoperable aneurysms. In the near future the method will probably be used to treat some of the surgically operable aneurysms as well.

Frequency of spondylolysis is higher among athletes who perform movements involving repeated flexion and extension of the spine than in the normal population. This article describes 50 patients (30 women, 20 men) with spondylolysis/spondylolisthesis grade 1 who were examined at the Norwegian Institute of Sports Medicine. Handball, followed by soccer, were the dominating sports in our study. Most of the patients were 15-19 years old; 20 patients had had low back pain for more than 12 months from onset till the first examination. In 45 patients the defect was found in the fifth lumbar vertebra, in three in L3 and in two in L4. This study indicates that stress fracture is the most dominating cause of spondylolysis in athletes.

This study was carried out to assess anatomic variations and pathologic changes associated with a potentially increased risk of complications during percutaneous nucleotomy. The MRI and CT examinations of 88 patients were reviewed with regard to the positional relationship between the trajectory to the disc and the bowel and iliac vessels respectively at the L4-L5 and L5-S1 levels. Pathologic conditions involving the anterior part of the annulus were assessed both by MRI and by CT-discography of 97 discs. The shortest distance from the needle course to the bowels was 29 mm. At ten other disc levels this distance was less than 40 mm. The position of the bowels is influenced by the size of the patient, the size and course of the psoas muscles and the amount of retroperitoneal fat. The bowels are at greaten distance from the trajectory at the L5-S1 than at the L4-L5 level. The risk of bowel puncture seems to be minimal. The iliac vessels were positioned behind the midportion of the disc in three patients. There was greater variation and a shorter distance to the trajectory at the L5-S1 than at the L4-L5 level. Anterior disc hernias, and particularly severe annular degeneration involving the anterior part of the annulus are frequently seen. These conditions include a weakening of the annulus and may increase the risk of anterior perforation during nucleotomy.

Follow-up CT of 106 pathological disks in 92 patients at a mean interval of 14 months after the initial examination revealed a strong association between the evolution of disc protrusions and clinical results, with a decrease in size of the majority of protrusions in successfully treated patients, whereas the others essentially remained unchanged (P< 0.0001). A significantly higher proportion of large protrusions diminished as compared to the smaller ones (P< 0.0001). Diffuse disc bulges were associated with a poor outcome and never regressed. There was a lower incidence of diminution of the central protrusions compared to other locations. Patients with normal disc spaces at the initial examination had better outcome than those with disc space narrowing. Only occasionally was a reduction of the disc space observed at follow-up.

The authors describe five years of experience of embolization in arteriovenous malformations and fistulas, aneurysms and tumours of the central nervous system and head and neck. Altogether 143 patients were embolized in 185 sessions. Polyvinyl alcohol particles and platinum fibre coils were used as embolic agents. Permanent complications were rare, e.g 5% in arteriovenous malformations of the brain. Embolizations were either complete or preoperatively incomplete and seemed to positively influence the final outcome for the patients. The authors advocate a policy which gives due consideration to the volume of patients who might benefit from this specialized neuroradiological activity.

In order to assess changes occurring in disk hernias and disk spaces following percutaneous nucleotomy a follow-up CT was carried out an average of 6 months after treatment of 69 disks in 60 patients. Forty-three of the disks were also reexamined at an average of 11 months after the first follow-up. Twenty-seven percent of the hernias were reduced in size at the first follow-up. Fourteen percent were reduced and 7% had increased between the first and second follow-ups. The medium-sized and large hernias were more frequently reduced compared to the smaller ones. Reduction of the disk space was found in 29% of the cases at first follow-up. An additional 24% were reduced between the first and second follow-ups. No association was demonstrated between change in size of the herniation or disk space and clinical outcome or amount of nucleus material removed at nucleotomy.

MR findings before and after transsphenoidal surgery were evaluated in 6 cases. T1-weighted (TR/TE 600/20) sagittal and coronal images with 2 or 4 acquisitions were obtained, using 3-mm slice thickness and 0.3-mm interslice gaps. Of 18 MR examinations, 13 included coronal i.v. contrast medium enhanced images. Image quality, sinus cavernosus invasion, identification of normal pituitary tissue and tumor size were examined. All MR studies clearly demonstrated the macroadenomas whether 2 or 4 acquisitions were used, and whether i.v. contrast medium was administered or not. Surgically confirmed sinus cavernosus infiltration was seen in 4 patients. The pituitary stalk was identified separate from the tumor in 2 patients, and the gland in one. There was reduction in tumor size over time, indicating that final radiologic assessment after transphenoidal surgery is best performed 4 to 6 months postoperatively. It should not be necessary to routinely include i.v. contrast medium injection in the postoperative evaluation of macroadenomas.

23 patients with intracranial arteriovenous malformations and durafistulas were embolized. 13 underwent embolization with polyvinylalcohol and silk threads as the only means of therapy, while six were also operated on, and four received radiation after considerable reduction of the nidus had been achieved. No death or major complications occurred in these patients. The authors considered the embolization to be successful in all cases.

Severe hyponatremia (serum sodium levels less than 120 mmol/l) is associated with increased morbidity and mortality. We report three cases where patients developed hyponatremia and severe neurological manifestations after medical treatment. The first two patients experienced episodes of general seizures and coma, but recovered in 24 hours without neurologic sequelae after correction of the electrolyte disturbance. The third patient developed the syndrome central pontine myelinolysis with pseudobulbar palsy and quadriparesis. Marked improvement occurred, however, and in three months the patient was almost completely recovered. The development of hyponatremia deserves special attention in connection with the use of diuretics, infusion of sodium-free carbohydrates and immediately after operation.

Magnetic resonance imaging (MRI) is a well documented method for diagnosis of spinal disease. We discuss the changes in the number of myelographies and spinal CT examinations carried out at our department after having had our own MRI unit for two years.

A randomized double blind crossover test with iohexol and the new non-ionic contrast medium iopentol in 12 patients undergoing carotid angiography showed no difference in tolerability, EEG, ECG, neurologic status or image quality. Iopentol seems to be well suited for cerebral angiography.

A randomized double blind crossover test with iohexol and the new non-ionic contrast medium iopentol in 12 patients undergoing carotid angiography showed no difference in tolerability, EEG, ECG, neurologic status or image quality. Iopentol seems to be well suited for cerebral angiography.

Eleven operated herniated disks in 10 patients were evaluated preoperatively with plain films, myelography and magnetic resonance imaging. Plain X-ray was a valuable supplement to MRI for studying the bony changes. Myelography showed 7 of 11 herniated disks while MRI gave correct diagnosis in all. It is concluded that MRI can replace myelography and computerized tomography in the preoperative evaluation of cervical herniated disk. The other examinations may be supplementary in some cases.

Cerebral panangiography was performed in 594 patients with subarachnoid hemorrhage from intracranial aneurysms. Aneurysm of the middle cerebral arteries was the most frequent location of aneurysms in this material. Multiple aneurysms of the middle cerebral arteries are far more frequent than the combination of other locations. Judged from this material there is a 7 per cent possibility of finding a contralateral aneurysm of the middle cerebral arteries if one is found. Multiple aneurysms were found in 51 (8.6%) of the 594 patients. We conclude that the results of this study are typical for Norwegians, although some selection exists since the patients were first admitted to other hospitals. The frequency of complications with cerebral panangiography in subarachnoid hemorrhage was less than that of cerebral angiography in patients with other diseases.

— Two patients with herpes zoster ophthalmicus (HZO) who experienced a delayed contralateral hemiparesis, the so-called crossed zoster syndrome, are described. Particular emphasis is paid to the cerebral blood flow (CBF) findings studied with the Xenon-133 inhalation technique using single photon emission computed tomography (SPECT). In a 40-year-old female with right-sided hemiparesis, angiography showed multiple segmental narrowings of the intracerebral arteries. Cerebral computer tomography (CT) scans were normal. The CBF studied 11 months after the HZO showed a generalized reduction of flow which, however, was more pronounced in the left hemisphere. On re-examination 8 months later both the mean hemispheric flow and regional CBF (rCBF) had increased to normal values. In a 66-year-old male with dysphasia and right-sided hemiparesis, cerebral CT scans demonstrated two small deep left-sided infarcts. CBF examination showed a generalized reduction of flow in the left hemisphere. The flow was slightly increased on re-examination 12 months later. These findings suggest that the Xenon-133 inhalation method represents a useful way to demonstrate the CBF pattern in this group of patients.

The purpose of this study was to evaluate possible vasoconstrictive or vasodilatator effects of the low osmolar non-ionic contrast medium iohexol (Omnipaque) on the calibre of cerebral arteries. The diameters of respectively 5 and 6 different locations of the vertebral and carotid arteries were recorded from angiograms of 3 successive injections. The material consisted of 18 patients. It could not be shown that Omnipaque induced vasoconstriction or vasodilatation when normal doses and adequate technique was applied. The difference in diameters found were not statistically significant and are probably due to natural pulsations and to the difficulties in performing exact measurements.