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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: 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.

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.

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.

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.

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.

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.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.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.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.

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.

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.

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.

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 (p0.0001). A significantly higher proportion of large hernias diminished as compared to the smaller ones (p0.0001). 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.

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.

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.

— 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.

A study of the diagnostic utility of both intravenous digital subtraction angiography (IV-DSA) and conventional angiography of precerebral and cerebral arteries is presented. The series comprised 60 patients with TIA, who underwent the two procedures with a mean interval of 16 days. Conventional angiography was generally superior to IV-DSA, and this was particularly marked in the siphons and cerebral arteries. Only the excellent IV-DSA examinations obtained in a few patients with TIA could be accepted as final pre-operative procedures. Accurate imaging of the lesions and collateral flow pattern usually required intra-arterial injections, and intra-arterial DSA is now usually preferred.

The myelography, CT and MR imaging findings in a patient with an epidural spinal arachnoid cyst are discussed. MR imaging excellently demonstrated cyst size, cyst location and cord compression, and should be the method of choice in these cases.

A randomized double-blind crossover study using Omnipaque 350 mg l/ml (iohexol) and Hexabrix 320 mg l/ml (ioxaglate) in 53 patients undergoing intravenous digital subtraction angiography of the carotid arteries revealed no significant differences in image quality. Some differences were found in subjective side effects that favored Omnipaque. Nausea was reported in four patients after injection of Hexabrix, and a metallic taste was significantly more frequent (p less than 0.01) with this contrast medium. The patients' preference for Omnipaque was also statistically significant (p less than 0.01). It was concluded that both contrast media are suitable for intravenous digital subtraction angiography.

Thirty patients underwent functional cervical myelography, i.e. radiographs in the lateral view were obtained in extension as well as in flexion of the neck. Sagittal tomography was performed in both positions. Widening of the subarachnoid space and decreased sagittal diameter of the spinal cord due to shortening were demonstrated in the lateral view in flexion. In some cases with advanced narrowing or spinal block in extension, such widening in flexion resulted in better diagnostic images by providing passage of the contrast medium caudally. Although iohexol (Omnipaque, Nyegaard & Co., Oslo) was regularly forced into the posterior cranial fossa by the movements, the frequency of side effects was approximately the same as in our former trials with iohexol in conventional cervical myelography. EEG changes occurred in two patients (7%). A sitting position for 3–4 min after the examination followed by an elevated head end of the bed was probably important for preventing side effects from the contrast medium. Specific questioning revealed twice as many subjective side effects as reported after general questions alone.