Prospective Study of Early MRI Appearances following Flow-Diverting Stent Placement for Intracranial Aneurysms.

BACKGROUND AND PURPOSE: MR imaging findings of aneurysm enlargement, aneurysm wall enhancement, perianeurysmal edema, and embolic phenomena following deployment of flow-diverting stents may be relevant to those patients who subsequently experience procedure-related intracranial hemorrhage. We sought to document the routine early postoperative MR imaging findings following flow-diverting stent insertion. MATERIALS AND METHODS: Patients requiring flow-diverting stent placement for treatment or retreatment of cerebral aneurysms were prospectively included in the study during a 26-month period. Early postprocedural MR imaging studies were obtained and compared with preoperative imaging. Patient clinical outcome data were also collected. RESULTS: There were 34 stent-placement procedures during the study period. Aneurysm mural enhancement and mild new perianeurysmal edema were present in 50% and 14%, respectively. Any DWI lesion was present in 57% of cases. New or possibly new foci of susceptibility effect were found ipsilateral to the stent and not associated with diffusion restriction in 66% of cases. There were 2 cases (6%) of parenchymal hemorrhage and 2 major clinical complications (6%) causing permanent morbidity. CONCLUSIONS: Asymptomatic aneurysm mural enhancement is frequently seen following flow-diverting stent placement and should not necessarily be interpreted as a sign of impending aneurysm rupture. This finding often persists despite complete aneurysm occlusion. New small brain parenchymal susceptibility foci following stent placement have not previously been reported, to our knowledge, but were common in our series.

Interventional radiology in the treatment of intracranial vascular injuries and fistulae.

Traumatic intracranial vascular injuries are uncommon. However prompt diagnosis and management is essential because of the high morbidity and mortality associated with these conditions. The imaging evaluation and potential endovascular management of traumatic intracranial aneurysms and traumatic intracranial fistulae is discussed.

Ethnic differences in syringomyelia in New Zealand.

OBJECTIVE: To determine the prevalence of syringomyelia in a defined population in New Zealand and measure the prevalence of syringomyelia in the three main ethnic groups (Maori, Pacific people and Caucasians/others) living in this region. METHODS: A retrospective study of all confirmed cases of syringomyelia diagnosed in residents of northern New Zealand from 1961 to 2003. RESULTS: In all, syringomyelia was diagnosed in 137 patients. The mean age at onset of symptoms was 27.5 years and mean age at diagnosis was 32.6 years. The incidence of new cases increased from 0.76/100,000 a year between 1962 and 1971 to 4.70/100,000 a year by 1992-2001. The prevalence of syringomyelia in 2003 was 8.2/100,000 people: 5.4/100,000 in Caucasians or others, 15.4/100,000 in Maori and 18.4/100,000 in Pacific people (chi2 = 37.0, p<0.0001). Syringomyelia was more often associated with an isolated Chiari I malformation in Pacific people (84.4%) as compared with 42.9% of Maori and 38.2% of Caucasians or others (chi2 = 62.3, p<0.0001). CONCLUSION: The prevalence of syringomyelia is higher in northern New Zealand than in studies carried out before the advent of magnetic resonance imaging. The prevalence is particularly high in Maori and Pacific people. The cause of the ethnic differences in the prevalence of syringomyelia identified in this study is unexplained and warrants further investigation.

Value of a contrast agent in equivocal carotid ultrasound studies: pictorial essay.

The aim of the present study was to assess the use of an echo-enhancing agent (Levovist; Schering AG) in equivocal carotid bifurcation ultrasound studies and compare the information obtained with digital subtraction angiography (DSA). Contrast-enhanced carotid ultrasound studies were performed on 30 carotid bifurcations in 28 patients. The standard carotid ultrasound examinations were considered equivocal for two reasons: apparent acute internal carotid artery occlusions (n = 10), and possibly patent but critically stenosed internal carotid arteries with the residual flow lumen being incompletely visualized (n = 20). All patients underwent subsequent carotid digital subtraction angiography. All patients with apparent acute carotid occlusions (n = 10) were correctly characterized on contrast-enhanced ultrasound when compared with DSA. The majority were complete occlusions (n = 8) although in two cases there were critical carotid stenoses requiring surgical endarterectomy. In the 'incompletely visualized lumen' group (n = 20), the majority (n = 16) were correctly characterized on contrast enhanced ultrasound: 13 cases of critically stenotic but patent internal carotid arteries, two cases without a haemodynamically significant stenosis and one case of a carotid occlusion with patent vasa vasorum. One of the critical carotid stenoses was prospectively reported as occluded on the 'gold standard' angiography. In three cases the flow lumen was still incompletely visualized due to calcified plaque despite an echo-enhancing agent; angiography revealed no significant stenosis in all cases. There was one false negative for internal carotid occlusion. This occurred early in the series and could be considered to be a technical error. Importantly, there were no false positives for carotid occlusion. Contrast-enhanced carotid ultrasound significantly improves diagnostic confidence in equivocal carotid ultrasound studies. In appropriate clinical settings this may reduce the need for subsequent carotid angiography.

Factors influencing successful angiographic occlusion of aneurysms treated by coil embolization.

BACKGROUND AND PURPOSE: Coil embolization of berry aneurysms is a relatively new treatment whose long-term efficacy has yet to be established. The purpose of this study was, first, to attempt to identify factors that might be important in predicting success both at the time of treatment and at the time of follow-up angiography, and, second, to study changes in the aneurysm between treatment and follow-up to determine the frequency of these changes. METHODS: The pretreatment, posttreatment, and follow-up angiograms of the first 63 aneurysms (in 58 patients) treated at our institution between June 1992 and April 1995 were analyzed, and the percentage of occlusion of each aneurysm was calculated. The size of any rest was noted for the posttreatment and follow-up angiograms. Treatment success was defined as a residue of less than 2 mm. Aneurysms were said to have changed if the percentage of occlusion had altered by more than 2.5% or if the difference in rest size was greater than 0.25 mm. Possible factors influencing primary and follow-up success rates were correlated against these calculations. RESULTS: Success rates at treatment and follow-up were 71% and 65%, respectively. No change occurred in 41% of aneurysms, and 20% had a decrease in size of the residue. Twenty-eight percent had coil compaction, and 11% had aneurysmal growth. Neck size was the only significant variable in primary treatment success. Success at follow-up correlated significantly with neck size, initial treatment success, vasospasm at the time of treatment, and clinical presentation. CONCLUSION: Best long-term angiographic results are obtained when the primary treatment is successful, when the aneurysm is small and narrow-necked, when the acutely ruptured aneurysm is treated within 15 days of ictus, and with anterior communicating and basilar-tip aneurysms.

Superficial siderosis of the central nervous system: a late complication of cerebellar tumors.

OBJECTIVE: To describe the clinical and radiologic features of superficial siderosis of the CNS after treatment of a cerebellar tumor. METHODS: Clinical assessment and MRI in four patients with superficial siderosis were performed. RESULTS: Four patients with superficial siderosis had been treated for a primary cerebellar tumor (astrocytoma in three patients, medulloblastoma in one patient) during childhood. All patients were treated with surgery and three received radiotherapy. Slowly progressive bilateral sensorineural hearing loss, gait ataxia, and limb ataxia appeared 8 to 22 years after diagnosis of the cerebellar tumor. Other clinical features were mild cognitive impairment, dysarthria, nystagmus, optic neuropathy, anosmia, and upper motor neuron signs. The CSF contained erythrocytes and increased protein. MRI with fast spin-echo T2-weighted and gradient-echo T2* sequences showed a hypointense rim of iron coating the surface of the cerebellum and brainstem. Twenty-one other patients who had survived more than 5 years after treatment of a primary cerebellar tumor did not have symptoms or signs suggestive of superficial siderosis. CONCLUSIONS: Superficial siderosis is an uncommon late complication of the treatment of a childhood cerebellar tumor, but it is probably underrecognized. The diagnosis should be suspected in patients who present with slowly progressive sensorineural hearing loss and ataxia many years after eradication of a childhood cerebellar tumor.

Anterior opercular syndrome, caused by herpes simplex encephalitis.

Bilateral frontal and parietal opercular lesions cause a syndrome characterized by paralysis of the masticatory, facial, pharyngeal, and tongue muscles (the anterior opercular syndrome). The anterior opercular syndrome can occur in patients with herpes simplex encephalitis (HSE), but in most of these patients the diagnosis of HSE was not confirmed. We describe the anterior opercular syndrome in four patients with HSE. In two of these patients, the anterior opercular syndrome dominated the clinical picture, but in the other two patients it was overshadowed by other manifestations of HSE. The diagnosis of HSE was confirmed by detection of herpes simplex virus (HSV) DNA in the CSF (two patients), culture of the HSV from a brain biopsy (one patient), and elevated HSV antibody titers in the CSF (one patient). Our patients made a partial recovery. Acute onset of weakness of masticatory, facial, pharyngeal, and glossal muscles, accompanied by fever, headache, and partial motor seizures of the face should suggest HSE.

The nature of thrombosis induced by platinum and tungsten coils in saccular aneurysms.

PURPOSE: To compare the efficacy and biocompatability of electrolytic and mechanically detachable embolization coils of two metal types. METHODS: Experimental saccular aneurysms in pigs were used to assess embolization induced by platinum or tungsten coils. Longitudinal angiographic and histologic studies were performed on treated and untreated (control) aneurysms to compare thrombosis and cellular responses after embolization with electrolytically detachable platinum coils and with mechanically detached tungsten coils. RESULTS: Fewer tungsten than platinum coils were needed to induce thrombosis. The inflammatory response within the aneurysmal lumen was more florid in embolized aneurysms than in control aneurysms. No difference was found in the timing or extent of accumulation of eosinophils, lymphocytes, or polymorphs between the two coils used. Giant cell responses were more marked in treated aneurysms; tungsten coils more than platinum coils. The amount of collagen and fibrosis present increased over the study period and was similar in treated and control aneurysms. CONCLUSION: The coil type influenced the initial cellular response but had little effect on the rate or degree to which blood clot within the aneurysm was replaced by fibrous tissue.

Three-dimensional CT angiography in the detection and characterization of intracranial berry aneurysms.

PURPOSE: To assess the accuracy of three-dimensional CT angiography (CTA) in the detection and characterization of intracranial aneurysms and to help determine its role as a screening test for aneurysms in the asymptomatic population and as an adjunct to angiography in subarachnoid hemorrhages and in the follow-up of untreated aneurysms. METHODS: In a blinded, prospective study, the 3-D CTA studies in 80 patients with symptomatic aneurysms were analyzed for the presence and morphology of aneurysms. Angiography or surgery acted as the control. RESULTS: Ninety-four aneurysms were found in 63 patients. Negative findings at angiography were noted in 17. Sensitivity and specificity of 3-D CTA for all aneurysms, all patients, and aneurysms 5 mm or smaller were 90.4% and 50%, 98.4% and 82.4%, and 78.8% and 51.9%, respectively. CONCLUSION: Three-dimensional CTA may have a role in noninvasive screening for asymptomatic aneurysms in the general population, but caution is advocated when data obtained from symptomatic patients are extrapolated to the asymptomatic population who harbor smaller aneurysms. Also, 3-D CTA may be useful as an adjunct to angiography in the characterization of berry aneurysms and in the follow-up of untreated aneurysms.

Racial differences between Maori and European New Zealanders in aneurysmal subarachnoid haemorrhage.

Racial differences in the incidence and rate of rupture of intracranial aneurysms are well recognized. A retrospective study of racial differences between Maori and European New Zealanders presenting to the Auckland Regional Neurosurgical Unit between 1985 and 1990 was conducted. It was found that the incidence per 100,000 of the population for all aneurysms was 14.3 for Europeans and 25.7 for Maoris. The mean age at rupture was 10 years earlier in Maoris with single aneurysms. A strong association between aneurysmal subarachnoid haemorrhage and cigarette smoking was found in both groups not only for single, but also for multiple aneurysms. Maoris were also found to have an abnormally high incidence of middle cerebral artery aneurysms and a low incidence of vertebrobasilar ones compared with Europeans.

Primary meningeal tumors in children: correlation of clinical and CT findings with histologic type and prognosis.

PURPOSE: To identify the radiologic features that might help in preoperative differentiation of the meningiomas from the remaining primary meningeal tumors, in particular the malignant tumors. METHODS: The clinical and computed tomographic features of 21 children with histologically proved primary meningeal tumors were analyzed. FINDINGS: Benign tumors (meningiomas) are more likely to occur in older children, to have longer symptom duration, and to have CT appearances similar to the "typical" adult meningioma. Atypical CT features suggest a malignant meningeal tumor, such as meningeal sarcoma, melanoma, or meningeal primitive neuroectodermal tumor. The recent identification of a new subtype of meningioma (a "sclerosing" group) is discussed. This is common in children and the CT and clinical features are similar to those seen in other meningiomas. It is frequently mistaken histologically for an intraaxial tumor, or for an atypical or malignant meningioma. These sclerosing meningiomas may also show brain invasion but despite this, in the short term, the prognosis is no different from other meningiomas. CONCLUSION: The bad reputation previously ascribed to childhood primary meningeal tumors should be confined to that small group that are malignant. Meningiomas have a more favorable outlook.

Meningeal tumors of childhood.

Meningeal tumors occurring in a pediatric hospital over a period of 18 years were studied. The incidence of meningeal sarcomas was much lower than has been previously reported. A histologic subtype of meningiomas was found which has not previously been described. In these "sclerosing" tumors only a small portion of the lesion contained viable cells, most of which bore little resemblance to conventional meningothelial cells. The bulk of the lesions consisted of whorling collagen bundles produced by the tumor. All cases in which there was tumor invasion of the brain fell into this category. The prognosis for the sclerosing meningiomas was similar to conventional meningiomas, casting doubt on the value of brain invasion as a marker of malignancy in childhood meningiomas. The recognition of this histologic type may aid diagnosis, guide surgical management, and possibly make postoperative radiotherapy unnecessary.

Cognitive and motor dysfunction in Parkinson's disease. Clinical, performance, and computed tomographic correlations.

The neuropathologic and pathophysiological relationship of specific to more generalized cognitive dysfunction in Parkinson's disease (PD) remains incompletely understood. This issue was examined in a study of 39 patients with PD, utilizing standardized clinical measures, computerized neuropsychological tests, and quantitative computed tomography. Disorders of visuospatial discrimination and perceptual-motor function closely paralleled motor scores, suggesting a common neuropathologic basis. Caudate nuclear and mesocortical dopamine depletion play a role in this context. More generalized cognitive dysfunction occurred in older patients with a somewhat longer disease duration, more advanced parkinsonism, and computed tomographic evidence of subcortical and frontal cortical atrophy but without significant cerebral atrophy when compared with age-matched controls. Further prospective clinicopathologic studies will be required to clarify the relative contribution of the primary dopaminergic dysfunction, age-related changes, Alzheimer-type pathologic condition, and other coexisting neurotransmitter deficits to the dementia seen in PD.

Peutz-Jeghers syndrome.

Peutz-Jeghers syndrome has now been widely reported. A case with previously unrecorded conjunctival pigmentation is presented and the management is reviewed.